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Background: Previously, we identified eight novel minisatellites in the MUC2, of which allelic variants in MUC2-MS6 were examined to influence susceptibility to gastric cancer. However, studies on the susceptibility to gastrointestinal cancer of other minisatellites in the MUC2 region still remain unprogressive. Objective: In this study, we investigated whether polymorphic variations in the MUC2-MS8 region are related to susceptibility to gastrointestinal cancer. Methods: We assessed the association between MUC2-MS8 and gastrointestinal cancers by a case–control study with 1229 controls, 486 gastric cancer cases, 220 colon cancer cases and 278 rectal cancer cases. To investigate whether intronic minisatellites affect gene expression, various minisatellites were inserted into the luciferase-reporter vector and their expression levels were examined. We also examined the length of MUC2-MS8 alleles in blood and cancer tissue matching samples of 107 gastric cancer patients, 125 colon cancer patients, and 85 rectal cancer patients, and investigated whether the repeat sequence affects genome instability. Results: A statistically significant association was identified between rare MUC2-MS8 alleles and the occurrence of rectal cancer: odds ratio (OR), 6.66; 95% confidence interval (CI), 1.11–39.96; and P = 0.0165. In the younger group (age, < 55), rare alleles were significant associated with an increased risk of rectal cancer (odds ratio, 24.93 and P = 0.0001). Suppression of expression was found in the reporter vector inserted with minisatellites, and loss of heterozygosity (LOH) of the MUC2-MS8 region was confirmed in cancer tissues of gastrointestinal cancer patients (0.8–5.9%). Conclusion: Our results suggest that the rare alleles of MUC2-MS8 could be used to identify the risk of rectal cancer and that this repeat region is related to genomic instability. [ABSTRACT FROM AUTHOR]

The rates and patterns by which cells acquire mutations profoundly shape their evolutionary trajectories and phenotypic potential. Conventional models maintain that mutations are acquired independently of one another over many successive generations. Yet, recent evidence suggests that cells can also experience mutagenic processes that drive rapid genome evolution. One such process manifests as punctuated bursts of genomic instability, in which multiple new mutations are acquired simultaneously during transient episodes of genomic instability. This mutational mode is reminiscent of the theory of punctuated equilibrium, proposed by Stephen Jay Gould and Niles Eldredge in 1972 to explain the burst-like appearance of new species in the fossil record. In this review, we survey the dominant and emerging theories of eukaryotic genome evolution with a particular focus on the growing body of work that substantiates the existence and importance of punctuated bursts of genomic instability. In addition, we summarize and discuss two recent studies from our own group, the results of which indicate that punctuated bursts systemic genomic instability (SGI) can rapidly reconfigure the structure of the diploid genome of Saccharomyces cerevisiae. [ABSTRACT FROM AUTHOR]

Enhanced recovery after surgery (ERAS) pathways are widely used in elective surgical procedures. The objective of this study was to evaluate the feasibility and efficacy of ERAS pathways in patients undergoing emergency surgery for perforated peptic ulcer (PPU). The single-centre prospective study was conducted in patients with PPU undergoing emergency open simple closure with Graham's patch technique were randomized into 42 patients in ERAS group and 43 patients in standard care group in the ratio 1:1. Patients with refractory shock, ASA ≥ 3 and multiple perforation and size > 1 cm were excluded. The outcomes were studied with length of hospitalization (LOH), functional recovery parameters and postoperative morbidity. LOH in ERAS group was significantly shorter (mean difference of 5.31 ± 1.102 days; p < 0.001). Patients in ERAS group had a significantly early functional recovery (days) for the time to first fluid diet (1.904 ± 0.72; p < 0.001), and first semi-solid diet (3.1 ± 0.48; p < 0.001), first stool (3.81 ± 0.76; p < 0.001) and removal of drain (2.19 ± 0.39: p < 0.001). There was a significant reduction in postoperative morbidity rate in ERAS group compared with standard care group. The application of enhanced recovery pathways in patients with perforated peptic ulcer undergoing emergency surgery is safe and feasible. [ABSTRACT FROM AUTHOR]

Abstract—The results of a study of delayed changes in the frequency of unstable chromosomal aberrations and the CNA- and LOH-genetic landscape of blood leukocytes in healthy employees at the main facilities of the Siberian Group of Chemical Enterprises exposed to external irradiation are presented. In 2014, 11 persons with de novo induced mosaic deletions and amplifications associated with dicentric and/or ring chromosomes (markers for individual radiosensitivity) were detected. Three years later, the frequency levels of chromosomal aberrations were compared. In 2017 the frequency of aberrant cells had increased by 1.7 times compared to 2014, the frequency of the chromosomal type aberrations had doubled, the frequency of pair fragments had a more than fourfold increase, and the frequency of dicentrics had almost doubled. The mosaic deletion in employee no. 1490 (3q12.3–13.11) identified in 2014 persisted until 2017. Mosaic amplifications identified in 2014 were preserved in five out of six employees (nos. 178, 203, 450, 1620, and 1792). Moreover, we identified that the CNstate in employee no. 450 had increased 1.5 times by 2017. The mosaic amplification of the short arm of the third chromosome in employee no. 278 had been eliminated by 2017. Other changes in the CNA and LOH-genetic landscape were not detected. Thus, these data indicate the formation of self-sustained bone marrow clones, whose descendants produce a population of aberrant cells in the blood of irradiated individuals. Further research into the preservation of chromosomal aberrations and CNA is needed, as well as studies aimed at detecting the clones of aberrant cells in the bone marrow. [ABSTRACT FROM AUTHOR]

The molecular pathogenesis of esophageal carcinosarcoma (ECS) has not been fully investigated. This study includes 16 consequent cases of surgically resected ECS. Genetic alterations were independently examined for carcinoma in situ, carcinomatous, and sarcomatous areas. Six cases were analyzed by next-generation sequencing, and the remaining cases were analyzed by Sanger sequencing for TP53, PTEN, and INI1. Sarcomatous components in 3 cases showed histologically heterogenous feature of osteosarcoma. Lymph node metastasis was found in 12 out of 16 cases. Survival analysis revealed 5-year overall survival rate of 59.9%, and the median survival time was 5.37 years. TP53 was the most frequently mutated gene, being identified in 11 of 16 patients (68.8%), 7 of whom (63.6%) had the same mutations in both carcinomatous and sarcomatous areas. Almost complete concordance was found between p53 immunohistochemistry and TP53 missense mutations. Five-year overall survival tended to be worse for patients with p53 overexpression, although the data was not significant (p = 0.186). Nine of 16 patients (56.3%) showed loss of heterozygosity (LOH) at the INI1 locus, and this LOH status was consistent with both components. However, interestingly, INI1 expression was preserved in all cases. In addition, copy number variation analysis revealed gene amplification in several tyrosine kinase receptors. Accumulation of mutations in tumor suppressor genes such as TP53 and INI1 seemed to occur during ECS development. [ABSTRACT FROM AUTHOR]

Gastric adenocarcinoma with enteroblastic differentiation (GAED) is a rare variant of aggressive adenocarcinoma. We demonstrated previously that GAED is genetically characterized by frequent TP53 mutation. In this study, we aimed to further clarify the mechanism of inactivation of TP53 in GAED in the light of promoter methylation of TP53, and expression of methylation-associated proteins such as Ten-eleven translocation (TET) 1 and 5-hydroxymethylcytosine (5-hmc) in addition to ATM mutations. We analyzed 51 cases of GAED. The ATM mutation was detected in only one case. Promoter methylation of TP53 was detected in 18% and frequency of loss of heterozygosity (LOH) at TP53 locus was 37.2%. Reduced TET1 expression was found in 29 cases (56.9%) and was significantly associated with advanced stage (p = 0.01), lymph node metastasis (p = 0.04), and macroscopic type (p = 0.01). Reduced 5-hmc expression was found in 28 cases (54.9%) and was significantly associated with advanced stage (p = 0.01), gender (p = 0.01), tumor location (p = 0.03), tumor size (p = 0.01), and lymph node metastasis (p = 0.01). Among 9 cases with TP53 promoter methylation, reduced expression of TET1 was observed in 6 cases, and reduced expression of 5-hmc was observed in 5 cases. Reduced expression of both TET1 and 5-hmc was significantly associated with adverse clinical outcomes. In summary, promoter methylation of TP53 is partly involved in loss of p53 expression. Aberrant methylation by reduced TET1 and 5-hmc may be involved in the development of aggressive GAED. [ABSTRACT FROM AUTHOR]

Esophageal adenocarcinoma (EAC) develops from Barrett's esophagus (BE), a condition where the normal squamous epithelia is replaced by specialized intestinal metaplasia in response to chronic gastroesophageal acid reflux. In a minority of individuals, BE can progress to low- and high-grade dysplasia and eventually to intra-mucosal and then invasive carcinoma. BE provides researchers with a unique model to characterize the process by which a carcinoma arises from its precursor lesion. Molecular studies of BE have demonstrated that it is not simply a metaplastic tissue, but rather it harbors frequent alterations that are also present in dysplastic BE and in EAC. Both BE and EAC are characterized by loss of heterozygosity, aneuploidy, specific genetic mutations, and clonal diversity. Epigenetic abnormalities, primary alterations in DNA methylation, are also frequently seen in BE and EAC. Candidate gene and array-based approaches have demonstrated that numerous tumor suppressor genes exhibit aberrant promoter methylation, and some of these altered genes are associated with the neoplastic progression of BE. It has also been shown that the BE and EAC epigenomes are characterized by hypomethylation of intragenic and non-coding regions Recent studies have also provided new insight into the evolutionary forces underlying the molecular alterations seen in BE and EAC and into the molecular pathogenesis of EAC. [ABSTRACT FROM AUTHOR]

Molecular mechanisms of lip squamous cell carcinoma (LSCC) and actinic cheilitis (AC) are unclear. We aimed at assessing loss of heterozygosity (LOH) and TP53 and BRAF V600E mutations in these lesions. Formalin-fixed paraffin-embedded (FFPE) samples of 17 LSCC and 16 AC were included, with additional 5 fresh LSCC genotyped for TP53 mutations. LOH was assessed by six polymorphic markers located at 9p22, 9q22, and 17p13 and correlated with cell proliferation (Ki-67) and P53 immunostaining. Direct sequencing of TP53 exons 2-11 (fresh samples), and exons 5-9 (FFPE samples) was carried out. BRAF V600E mutation was genotyped in eight LSCC. LOH occurred in at least one marker in 15/17 LSCC and in 9/16 AC. The marker exhibiting the highest frequency of allelic loss (FAL) in LSCC was D9S157 (8/12 informative cases) and D9S287 in AC (4/11 informative cases). Cell proliferation was not correlated with LOH or with the FAL and no correlation between P53 IHC and 17p LOH was observed. We found TP53 missense mutations in both lesions and nonsense in LSCC, including CC>TT transition, which is a marker of UV damage. BRAF V600E mutation was not detected. LOH and TP53 mutations detected in LSCC and AC may be associated with tumorigenesis, whereas BRAF V600E mutation does not seem to significantly contribute to LSCC pathogenesis. [ABSTRACT FROM AUTHOR]

Purpose: Many men with 'late-onset hypogonadism' (LOH) experience lower urinary tract symptoms (LUTS) that can be distressing and may decrease quality of life. LUTS often appear in men when testosterone levels begin to decline, which could be a significant association. We investigated whether testosterone replacement could alleviate LUTS in men with LOH. Methods: Two hundred and sixty-one hypogonadal patients (mean age 59.5 years) presenting with erectile dysfunction, having also been evaluated for LUTS, received a single testosterone undecanoate injection at day 1, at week 6 and quarterly thereafter. Parameters, including International Prostate Symptom Score (IPSS), post-voiding residual urine volume, transrectal ultrasound, prostate volume and prostate-specific antigen were measured at each treatment visit. Two hundred and fifty-nine patients were included in the full analysis set. These were subsequently divided into weight losers (L ≥ 5 % weight loss at last visit from baseline) and non-losers (NL). t test analyses were used to compare the IPSS means of these subgroups. The potentially confounding effect on IPSS of using the phosphodiesterase-5 inhibitor (PDE5i) vardenafil was also accounted for. Results: Mean IPSS showed a significant decrease with time following initiation of testosterone treatment ( p < 0.05). No significant differences were observed in either IPSS between L and NL groups or in mean IPSS between vardenafil users and non-users. Conclusion: Testosterone replacement is associated with improvements in LUTS which are not confounded by weight loss or PDE5i. The mechanisms of this association require further investigation. [ABSTRACT FROM AUTHOR]

Purpose: NF2/Merlin was first identified through its association with neurofibromatosis type 2 (NF2). However, accumulating evidence suggests a more general involvement in tumorigenesis and, in particular, a broader role in tumor suppression. The aim of this study was to examine NF2/Merlin involvement in sporadic colorectal cancer. Methods: This study is the first to examine the role of NF2/Merlin in sporadic colorectal cancer through LOH analysis at the NF2 locus and mRNA expression analysis via quantitative RT-PCR of total NF2, NF2 isoform I and II. In addition, Merlin protein expression was assessed by immunohistochemistry and Western blotting. Results: NF2 LOH was detected in 20.0 % of heterozygous cases and was found to be more frequent in tumors larger than 5 cm in diameter ( p = 0.041) and in tumors with a less differentiated phenotype ( p = 0.027). No differences were observed in total NF2 and NF2 isoform I/isoform II mRNA expression between the tumors and their corresponding normal mucous tissues. NF2 isoform II was the most predominant isoform in all samples analyzed. mRNA expression levels of total NF2 and isoforms I and II were significantly lower in poorly differentiated tumors ( p = 0.033, p = 0.036 and p = 0.044, respectively). Weak Merlin immunostaining was more frequent in poorly differentiated tumors ( p = 0.034) and tumors classified as Dukes' C ( p = 0.023). A distinct pattern of Merin phosphorylation was observed in tumors compared to normal mucous tissues. Conclusion: Our data indicate that NF2/Merlin may serve as a potential target in the management of colorectal cancer. [ABSTRACT FROM AUTHOR]

Somatic inactivation of the remaining allele is a characteristic feature of cancers arising in BRCA1 and BRCA2 mutation carriers, which determines their unprecedented sensitivity to some DNA-damaging agents. Data on tumor-specific status of the involved gene in novel varieties of hereditary breast cancer (BC) remain incomplete. We analyzed 32 tumors obtained from 30 patients with non-BRCA1/2 BC-associated germ-line mutations: 25 women were single mutation carriers (7 BLM, 15 CHEK2 and 3 NBN/NBS1) and 5 were double mutation carriers (2 BLM/BRCA1, 1 CHEK2/BLM, 1 CHEK2/BRCA1 and 1 NBN/BLM). Losses of heterozygosity affecting the wild-type allele were detected in none of the tumors from BLM mutation carriers, 3/18 (17 %) CHEK2-associated BC and 1/4 (25 %) NBN/NBS1-driven tumors. The remaining 28 BC were subjected to the sequence analysis of entire coding region of the involved gene; no somatic mutations were identified. We conclude that the tumor-specific loss of the wild-type allele is not characteristic for BC arising in CHEK2, NBN/NBS1 and BLM mutation carriers. Rarity of 'second-hit' inactivation of the involved gene in CHEK2-, NBN/NBS1- and BLM-associated BC demonstrates their substantial biological difference from BRCA1/2-driven cancers and makes them poorly suitable for the clinical trials with cisplatin and PARP inhibitors. [ABSTRACT FROM AUTHOR]

The biological behavior of prostate cancer is uncertain, and therefore, search for molecular prognostic markers associated with disease progression seems to be essential. We performed microsatellite allelotyping of DNA isolated from primary prostate tumors biopsies (prostate adenocarcinoma, PCa). We evaluated the frequency of allelic imbalance (AI), including loss of heterozygosity and/or microsatellite imbalance (LOH/MSI) as well as the association of these DNA alterations with clinicopathological variables. We assessed the significance of LOH/MSI alterations in selected imprinted and non-imprinted chromosomal regions (IR and NIR) in PCa. A total of 50 biopsies of prostate tumor (containing >75 % tumor cells) were histologically examined confirming prostate carcinoma. Microsatellite allelotyping using 16 microsatellite markers linked to the following chromosomal regions: 1p31.2, 3p21.3-25.3, 7q32.2, 9p21.3, 11p15.5, 12q23.2, and 16q22.1 was performed. The incidence of LOH/MSI alterations in prostate tumor cells was the highest for chromosomal regions 7q32.2 and 16q22.1 (31.25 and 26.60 %, respectively), followed by 1p31.2 and 3p21.3-25.3 (26.50 and 17.40 %, respectively). Statistically significant increase in LOH/MSI alterations has been observed for markers: D1S2137 (1p region; p = 0.00032), D9S974 (9p region; p = 0.0017), and D16S3025 (16q region; p = 0.0017). Statistically significant differences in frequency of LOH/MSI alterations in particular chromosomal regions have been found for 1p31.2, 7q32.2 and 16q22.1 ( p = 0.027, p = 0.012 and p = 0.031, respectively). We documented statistically significant association between Fractional Allele Loss (FAL) index and advanced tumor stage ( p < 0.05). We suggest that genomic instability of LOH/MSI type is a frequent event in prostate carcinogenesis and assessed as FAL index has clinical value for the molecular staging of prostate cancer in (TRUS)-guided prostate biopsy material. [ABSTRACT FROM AUTHOR]

Breast cancer is a heterogeneous disease, previously associated with genomic instability. Our aim was to analyze microsatellite markers in order to determine patterns and levels of instability, as well as possible correlations with histopathological parameters. Polymerase chain reaction was used to characterize microsatellite instability (MSI) and loss of heterozygosity (LOH) in 107 breast carcinomas at twelve microsatellite loci. Some of the markers were selected because of their relation to steroid hormone metabolism, which seems to be related to sporadic breast cancer risk. D5S346 and D17S250 markers showed a statistically significant frequency of MSI. LOH in D3S1611, D17S250, AR and ER-β were associated with some parameters of worse prognosis. Marker group analysis showed that CYP19, AR and ER-β were related to histological grade III, ER-negative and PR-negative cases. Our results suggest that marker group analysis may be preferred to the single marker strategy, being predictive of worst prognosis when single markers are unable to provide such information. A further evaluation of steroid metabolism genes and their association with low penetrance genes in breast cancer may be useful. [ABSTRACT FROM AUTHOR]

Thyroid hormone receptors (TR), ligand-mediated transcription factors, regulate cell growth, differentiation, and apoptosis. In humans, two different genes encode TR-α and TR-β and they are often co-expressed in various tissues at different levels. To explore the role of TR in esophageal cancer, we analyzed expression of TR-β1 mRNA (most abundantly expressed in the majority of normal cells) in normal and malignant esophageal tissue specimens using in situ hybridization. The TR-β1 mRNA was detected in 92.3% (96 of 104) of normal esophageal mucosa, whereas TR-β1 mRNA was only detected in 55.8% (58 of 104 cases) of esophageal squamous cell carcinoma specimens ( P < 0.00001). Expression of TR-β1 mRNA was associated with well-differentiated cancers ( P < 0.001). Furthermore, we determined whether the loss of heterozygosity (LOH) in TR-β gene locus would be responsible for the lost TR-β1 expression. Analysis of 73 esophageal tissue specimens generated 39 informative cases, 17 of which showed LOH (43.6%) but only 9 of these 17 cases were correlated with lost TR-β1 expression. This study demonstrated that expression of TR-β1 mRNA was lost in esophageal cancer tissues, which may be due to multiple mechanisms. [ABSTRACT FROM AUTHOR]

Introduction: Ductal carcinoma in situ (DCIS) is considered to be related to the development of invasive breast cancer. The aim of molecular biological research of preinvasive breast lesion characteristics and comparison with normal tissues and tissue of invasive tumours is to identify patients at high risk of developing invasive tumour on the basis of already established preinvasive lesions, and thus influence clinical decision-making. The aim of our study was to analyse several key molecules involved in different cellular pathways important for cancer development and progression in different types of breast tissue and to describe similarities and differences between premalignant and malignant lesions. Material and methods: Genetic material isolated from both the tumour and healthy tissue was examined by loss of heterozygosity (LOH) analysis and real-time PCR using collagen 2A as a house-keeping gene. Results: We analysed 65 samples of healthy mammary gland, 25 DCIS and 42 invasive ductal breast cancer samples. We analysed the LOH in three genes: BRCA1, BRCA2 and p53; and the gene expression of the VEGF gene and Bcl-2 gene. LOH in the BRCA1 gene was present in 44.74% of invasive samples and in 8.69% of DCIS ( p=0.026); LOH in the BRCA2 gene in 45.0% of invasive samples and in 9.52% of DCIS ( p=0.036); LOH in the p53 gene in 32.5% of invasive samples and in 31.82% of DCIS ( p=0.97). No LOH was observed in normal tissue samples. VEGF was overexpressed in 14.3% of invasive cancers and in 12.0% of DCIS. Overexpression of Bcl-2 was observed in 11.9% of invasive cancers and in 8.0% of DCIS. Conclusion: We have confirmed that some of the molecular characteristics of DCIS are identical to those of invasive carcinoma. This approach could lead to the identification of molecular markers as indicators for the potential development of DCIS into invasive carcinoma or identification of DCIS subgroups with latent invasion. [ABSTRACT FROM AUTHOR]

Copyright of Der Urologe A is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Despite recent advances in the diagnosis and treatment of glioblastomas, patient outcomes for these highly malignant tumors remain poor. Research into the molecular pathology of glioblastoma has uncovered various genetic changes that contribute to malignancy. Some of the identified molecular markers-such as loss of heterozygosity (LOH) on chromosome 1p/19q and chromosome 10, O6-methylguanine methyltransferase promoter hypermethylation, and mutation of isocitrate dehydrogenase-1-may help to predict patient outcomes. Indeed, LOH analysis is an effective approach to classify malignant gliomas. Genome-wide analyses have revealed that the extent and pattern of LOH regions may have important implications for the clinical course of the disease. As the genetic underpinnings of malignant gliomas are complex and varied, careful selection of the methods for genetic analysis in the clinic is important. The fundamental principles of each assay need to be understood to allow careful selection of practically useful methods. This review summarizes recent developments in the molecular analysis of malignant glioma. [ABSTRACT FROM AUTHOR]

Methylation of the MGMT promoter is supposed to be a predictive and prognostic factor in glioblastoma. Whether MGMT promoter methylation correlates with tumor response to temozolomide in low-grade gliomas is less clear. Therefore, we analyzed MGMT promoter methylation by a quantitative methylation-specific PCR in 22 patients with histologically verified low-grade gliomas (WHO grade II) who were treated with temozolomide (TMZ) for tumor progression. Objective tumor response, toxicity, and LOH of microsatellite markers on chromosomes 1p and 19q were analyzed. Histological classification revealed ten oligodendrogliomas, seven oligoastrocytomas, and five astrocytomas. All patients were treated with TMZ 200 mg/m on days 1-5 in a 4 week cycle. The median progression-free survival was 32 months. Combined LOH 1p and 19q was found in 14 patients; one patient had LOH 1p alone and one patient LOH 19q alone. The LOH status could not be determined in two patients and was normal in the remaining four. LOH 1p and/or 19q correlated with longer time to progression but not with radiological response to TMZ. MGMT promoter methylation was detectable in 20 patients by conventional PCR and quantitative analysis revealed the methylation status was between 12 and 100%. The volumetric response to chemotherapy analyzed by MRI and time to progression correlated with the level of MGMT promoter methylation. Therefore, our retrospective case series suggests that quantitative methylation-specific PCR of the MGMT promoter predicts radiological response to chemotherapy with TMZ in WHO grade II gliomas. [ABSTRACT FROM AUTHOR]

The WWOX gene is a tumour suppressor gene affected in various types of malignancies. Numerous studies showed either loss or reduction of the WWOX expression in variety of tumours, including breast, ovary, liver, stomach and pancreas. Recent study demonstrated that breast cancer patients exhibiting higher WWOX expression showed significantly longer disease-free survival in contrast to the group with lower relative WWOX level. This work was undertaken to show whether similar phenomena take place in colon tumours and cell lines. To assess the correlation of WWOX gene expression with prognosis and cancer recurrence in 99 colorectal cancer patients, we performed qRT-PCR analysis. We also performed analysis of WWOX promoter methylation status using MethylScreen method and analysis of loss of heterozygosity (LOH) status at two WWOX-related loci, previously shown to be frequently deleted in various types of tumours. A significantly better disease-free survival was observed among patients with tumours exhibiting high level of WWOX (hazard ratio = 0.39; p = 0.0452; Mantel-Cox log-rank test), but in multivariate analysis it was not an independent prognostic factor. We also found that although in colorectal cancer WWOX expression varies among patients and correlates with DFS, the exact mode of decrease in this type of tumour was not found. We failed to find the evidence of LOH in WWOX region, or hypermethylation in promoter regions of this gene. Although we provide the evidence for tumour-suppressive role of WWOX gene expression in colon, we were unable to identify the molecular mechanism responsible for this. [ABSTRACT FROM AUTHOR]

Downregulation or total loss of HLA class I expression on tumor cells is known as a mechanism of cancer immune escape. Alterations of the HLA phenotype are frequently due to mutations affecting genes encoding the HLA class I heavy chains located on chromosome 6p21 or the β2-microglobulin (β2m) gene encoding the light chain of the HLA complex located on chromosome 15q21. Frequently irreversible total loss of HLA class I molecules is due to the coincidence of two molecular events, the mutation of one β2m gene and the loss of the second copy. The latter is detectable as loss of heterozygosity (LOH) of microsatellite markers in the β2m region on chromosome 15q21 (LOH-15q21). Thus, LOH-15q21 might be an important event in the processes of HLA class I downregulation and total loss. Here we studied the frequency of LOH-15q21 in tumor tissues of different entities. By determining the status of heterozygosity of two microsatellite markers we detected LOH-15q21 in 44% of bladder carcinomas ( n = 69), in 35% of colon carcinomas ( n = 95), in 16% of melanomas ( n = 70) but only in 7% of renal cancers ( n = 45). Moreover, we observed a frequent coincidence of LOH-15q21 and LOH-6p21 in colorectal carcinoma, bladder carcinoma and melanoma, but not for renal carcinoma. We believe that the high incidence of LOH-15q21 in some malignancies and especially the coincidence of LOH-15q21 and LOH-6p21 might have a strong impact on tumor immunogenicity and on the efficiency of cancer immunotherapy. [ABSTRACT FROM AUTHOR]

Alterations in the p16/cyclinD1/Rb and ARF/Mdm2/p53 pathways are frequent events in the pathogenesis of squamous cell carcinomas. Different mechanisms of p16 regulation have been described for penile carcinomas so far. Therefore, expression of p16 and p53 was immunohistochemically detected with monoclonal antibodies in 52 primary invasive penile squamous cell carcinomas. The carcinomas were analyzed for allelic loss (LOH) in p16(INK4A) and p53, as well as for mutations in the p16(INK4A) and the p53 gene. In addition, we examined the promoter status of p16(INK4A) by methylation-specific PCR. The presence of human papilloma virus (HPV) 6/11, HPV 16 and HPV 18 DNA was analyzed by PCR. Data were compared to clinical data. Concerning p16, 26 (50%) tumors showed positive immunohistochemistry, 32 (62%) tumors showed allelic loss and 22 tumors (42%) showed promoter hypermethylation. All tumors with negative p16 immunohistochemistry showed LOH near the p16(INK4A) locus and/or hypermethylation of the p16(INK4A) promoter. HPV 16 DNA was detected in 17 tumors, ten of them with positive p16 immunostaining. The remaining seven tumors with negative p16 staining showed allelic loss and/or promoter hypermethylation. Evidence of lymph node metastasis was significantly associated with negative p16 immunohistochemistry as well as with combined LOH and promoter hypermethylation (p = 0.003 and p = 0.018, respectively). Allelic loss around p53 was found in 22 tumors (42%), and seven mutations of the p53 gene could be demonstrated in our tumors. No correlations could be found between any p53 alteration and clinical parameters. [ABSTRACT FROM AUTHOR]

Glioblastoma multiforme is the most common type of primary brain tumor in adults. WWOX is a tumor suppressor gene involved in carcinogenesis and cancer progression in many different neoplasms. Reduced WWOX expression is associated with more aggressive phenotype and poor patient outcome in several cancers. We investigated alternations of WWOX expression and its correlation with proliferation, apoptosis and signal trafficking in 67 glioblastoma multiforme specimens. Moreover, we examined the level of WWOX LOH and methylation status in WWOX promoter region. Our results suggest that loss of heterozygosity (relatively frequent in glioblastoma multiforme) along with promoter methylation may decrease the expression of this tumor suppressor gene. Our experiment revealed positive correlations between WWOX and Bcl2 and between WWOX and Ki67. We also confirmed that WWOX is positively correlated with ErbB4 signaling pathway in glioblastoma multiforme. [ABSTRACT FROM AUTHOR]

ims: EphB2 is a member of the Eph receptor tyrosine kinase family that has been involved in the regulation of cytoskeleton organization and cell migration in various cell types. Its role and regulation in carcinogenesis is controversial, especially in gastric cancer. We detected EphB2 expression and determined its clinical significance and explored its underlying molecular mechanism in gastric cancers. Methods: Tissue microarray blocks containing primary gastric cancer, lymph node metastases, and adjacent normal mucosa specimens obtained from 337 Chinese patients were constructed. Expression of EphB2 in these specimens was analyzed using immunohistochemistry. Mutation analysis at the A9 tract in exon 17 and loss of heterozygosity analysis at the EphB2 gene locus were carried out in 13 sporadic EphB2-negative gastric cancers. Results: Complete loss of EphB2 expression was observed in 177 (52.5%) of the 337 primary tumor and 41 (82%) of the 50 nodal metastases. Loss of EphB2 expression was significantly associated with advanced T stage, nodal metastasis, advanced disease stage, and poor histological differentiation. Loss of EphB2 expression correlated significantly with poor survival rates in both univariate and multivariate analysis. No frameshift mutation, but a higher frequency of allelic loss, was found in EphB2-negative primary and metastatic tumor samples. Conclusions: Frequent deletion and decreased expression of EphB2 protein suggested it as a negative biomarker for gastric carcinogenesis and a potential predictor of the outcome of patients with gastric cancer. [ABSTRACT FROM AUTHOR]

A small but significant percentage of patients that Neuroblastomas (NB) are the most common solid tumour in children under the age of five. The aetiology remains unknown, although it has been associated with several genes, such as MYCN in chromosome 17q and LOH in chromosome 1q. The incidence of the disease is 1/100,000 children. Clinical signs and symptoms vary according to the age of patient, the stage of NB, metastases and the secretion of several metabolic products by the tumour. Ninety per cent of NB produces catecholamines. Diagnosis is usually based on characteristic histological findings. According to the Children’s Study Group (CSG) and the International Neuroblastoma Staging System (INSS) NB has four stages. The therapeutic approach is based on the stage of the disease, while age, stage of disease, histological and biological markers are used to predict prognosis. In conclusion, given that correct treatment and prognosis depend mainly on the stage of NB, we urge great care in the staging of the disease. [ABSTRACT FROM AUTHOR]

Copyright of Der Urologe A is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Loss of heterozygosity (LOH) is implicated in the initiation and progression of various human neoplasia, and is observed in both early or in advanced-stage human cancers. The current study was aimed at investigating the frequency of LOH TP53 in human endometrial carcinoma (EC) metastases. LOH was analyzed using 3 intragenic polymorphisms in 38 primary ECs and corresponding metastatic lesions. Allelic loss at intron 1 was detected in 14 out of 38 (37%) primary carcinomas and in 11 out of 38 (29%) metastatic lesions. LOH at intron 1 in primary and metastatic tumors was concomitantly noted in 8 out of 38 (21%) cases. LOH at intron 4 was seen in 46% (17 out of 37) primary ECs and in 35% (13 out of 37) metastatic lesions. LOH at intron 4 in primary tumor/metastasis was concomitantly demonstrated in 27% (10 out of 33) cases. Allelic loss at exon 4 was detected in 5 out of 33 (15%) primary ECs and in one out of 33 (3%) corresponding metastases. Coexistence of LOH TP53 in primary ECs with metastases at intron 1 and intron 4 was observed in three out of 33 (9%) cases. Correlation between allelic loss at intron 1 in primary ECs and corresponding metastases was found ( R = 0.475, p = 0.003). Moreover, there was correlation between LOH at intron 1 in metastastic ECs and allelic imbalance at intron 4 in primary uterine tumors ( R = 0.416, p = 0.01). There was a relationship between LOH at intron 4 in primary ECs and corresponding metastatic lesions ( R = 0.457, p = 0.004). LOH TP53 at intron 4 correlated with the presence of the neoplasm in the uterine cervix ( R = 0.319, p = 0.049), and with the non-endometrioid type of primary tumor ( R = 0.371, p = 0.024). There was a significant correlation between exon 4 LOH and patient age (less or equal to 50 years and above this age; R = −0.375, p = 0.032). p53 overexpression was present in thirteen out of 38 (34%) cases, both in primary ECs and in metastatic lesions. Overexpression of p53 was higher in non-endometrioid ECs (three out of 5; 60%) than in endometrioid-type uterine tumors (ten out of 33; 30.3%; p = 0.315). p53 overexpression correlated with the presence of cancer in the lumen of fallopian tube(s) ( R = 0.032, p = 0.046), and with allelic loss at intron 1 in primary ECs ( R = 0.599, p = 0.0001). In conclusion, LOH occurs not only in primary uterine tumors but also in corresponding metastases, with the higher incidence being reported at intron 4 of the TP53. A significant link existed between LOH TP53 at intron 1 and p53 overexpression in primary ECs, but not in the corresponding metastatic lesions. [ABSTRACT FROM AUTHOR]

Loss of heterozygosity (LOH) in the ING family members has been shown in head and neck squamous cell carcinoma (HNSCC) except for ING2. Like all the other members of ING family, ING2, which is located at chromosome 4q35.1, is a promising tumor suppressor gene (TSG). In this study, we performed LOH analysis of ING2 in HNSCC and compared it with clinicopathological variables. We performed LOH analysis in DNAs from 80 paired of normal and HNSCC tissues, using a specifically designed microsatellite marker on chromosome 4q35.1, which detects allelic loss of ING2. TP53 mutation analysis and its relationship with ING2 chromosomal deletion were also performed in available 68 of the samples. The correlation between LOH status and clinicopathological characteristics was evaluated by using statistical methods. The overall survival (OS) and disease free survival (DFS) were also determined. LOH was detected in 54.6% (30/55) of the informative samples. Statistical significance was obtained between LOH and tumor (T) stage ( P = 0.02), application of radiotherapy and chemotherapy. Positive node status (N) appeared to be the only independent prognostic factor for both OS ( P = 0.031) and DFS ( P = 0.044). Our study showed allelic loss of 4q35.1 in HNSCC. The high percentage of LOH suggests ING2 as a candidate TSG in HNSCC. High LOH frequency was statistically associated with advanced T stage, suggesting that ING2 LOH might occur in late stages during HNSCC progression. [ABSTRACT FROM AUTHOR]

This project explored the influence of loss of heterozygosity (LOH) and microsatellite instability (MSI) of locus D8S277 to PINX1 expression of gastric cancer in Chinese people. LOH and MSI of locus D8S277 in 90 paraffin-embedded gastric carcinoma specimens were detected by polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP). Envision immunohistochemistry was used to assess the expression of PINX1. The frequency of LOH was higher in cases with lymph node metastasis than those without (18.57 vs. 0.00%, P < 0.01), and was higher in the specimens that were at TNM stage III + IV than those at stage I + II (21.43 vs. 2.94%, P < 0.01). In terms of the frequency of MSI, it was lower in cases with lymph node metastasis than those without (10.00 vs. 30.00%, P < 0.05). The positive rate of PINX1 protein was higher in samples without lymph node metastasis than those with lymph node metastasis (80.00 vs. 50.00%, P < 0.01); and was higher in the cases at TNM stage I + II than those at stage III + IV; and was lower in the cases between 40 and 60 years old than those above 60 years old (43.75 vs. 65.52%, P < 0.05). LOH and MSI of PINX1 may play major role in tumor development and regulate it through different pathways. Because LOH plays a major role in negative expression of PINX1, it can be regarded as a sign of gastric cancer development and MSI may affect the prognosis and tumor turnover. [ABSTRACT FROM AUTHOR]

This study assessed the prognostic value of several markers involved in gliomagenesis, and compared it with that of other clinical and imaging markers already used. Four-hundred and sixteen adult patients with newly diagnosed glioma were included over a 3-year period and tumour suppressor genes, oncogenes, MGMT and hTERT expressions, losses of heterozygosity, as well as relevant clinical and imaging information were recorded. This prospective study was based on all adult gliomas. Analyses were performed on patient groups selected according to World Health Organization histoprognostic criteria and on the entire cohort. The endpoint was overall survival, estimated by the Kaplan-Meier method. Univariate analysis was followed by multivariate analysis according to a Cox model. p14(ARF), p16(INK4A) and PTEN expressions, and 10p 10q23, 10q26 and 13q LOH for the entire cohort, hTERT expression for high-grade tumours, EGFR for glioblastomas, 10q26 LOH for grade III tumours and anaplastic oligodendrogliomas were found to be correlated with overall survival on univariate analysis and age and grade on multivariate analysis only. This study confirms the prognostic value of several markers. However, the scattering of the values explained by tumour heterogeneity prevents their use in individual decision-making. [ABSTRACT FROM AUTHOR]

Although several familial cancer genes with high-penetrance mutations have been identified, the major genetic component of susceptibility to sporadic cancers is attributable to low-penetrance alleles. These ‘weak’ tumor susceptibility genes do not segregate as single Mendelian traits and are therefore difficult to find in studies of human populations. Previously, we have proposed that a combination of germline mapping and analysis of allele-specific imbalance in tumors may be used to refine the locations of susceptibility genes using mouse models of cancer. Here, we have used linkage analysis and congenic mouse strains to map the major skin tumor susceptibility locus Skts1 within a genetic interval of 0.9 cM on proximal chromosome 7. This interval lies in an apparent recombination cold spot, and corresponds to a physical distance of about 15 Mb. We therefore, used patterns of allele-specific imbalances in tumors from backcross and congenic mice to refine the location of Skts1. We demonstrate that this single tumor modifier locus has a dramatic effect on the allelic preference for imbalance on chromosome 7, with at least 90% of tumors from the congenics showing preferential gain of markers on the chromosome carrying the susceptibility variant. Importantly, these alterations enabled us to refine the location of Skts1 at higher resolution than that attained using the congenic mice. We conclude that low-penetrance susceptibility genes can have strong effects on patterns of allele-specific somatic genetic changes in tumors, and that analysis of the directionality of these somatic events provides an important and rapid route to identification of germline genetic variants that confer increased cancer risk.Oncogene (2007) 26, 4171–4178; doi:10.1038/sj.onc.1210206; published online 19 February 2007 [ABSTRACT FROM AUTHOR]

Inactivation of the HRPT2 gene encoding parafibromin was recently linked to the familial hyperparathyroidism-jaw tumor syndrome. Patients with this syndrome carry an increased risk of parathyroid and renal tumors. To determine the relevance of HRPT2 for sporadic renal tumors, clear cell, papillary and chromophobe renal cell carcinomas as well as oncocytomas and Wilms tumors were analysed for HRPT2 gene alterations. Loss of heterozygosity (LOH) of HRPT2 was found in seven of 56 (12.5%) clear cell, three of 14 (21%) papillary, six of 10 (60%) chromophobe renal cell carcinomas, three of eight (38%) oncocytomas and four of 10 (40%) Wilms tumors. In addition, two novel HRPT2 point mutations, causing K34Q and R292K changes in parafibromin, were detected in one clear cell carcinoma and one Wilms tumor, respectively. These tumors displayed LOH of the remaining wild-type allele, but interestingly no von Hippel–Lindau (VHL) mutation. Functional analysis revealed that the K34Q mutant species of parafibromin is, unlike wild-type protein, defective in suppressing cyclin D1 expression in vivo. Taken together, these results suggest that renal cancer-associated mutations in parafibromin occur in the absence of VHL mutation, which in turn may contribute to constitutively elevated cyclin D1 expression and abnormal cell proliferation.Oncogene (2007) 26, 3440–3449. doi:10.1038/sj.onc.1210131; published online 27 November 2006 [ABSTRACT FROM AUTHOR]

Hereditary non-polyposis colorectal cancer (HNPCC) is caused by germline mutations in mismatch repair (MMR) genes, mostly MLH1 and MSH2. Somatic inactivation of the wild-type allele of the respective MMR gene is required for tumor development. Unexpectedly, a recent study utilizing DNA from paraffin-embedded tissue material detected frequent loss of the mutant MMR gene allele in HNPCC tumors. Dual role for loss of heterozygosity (LOH) was proposed. If somatic loss of the wild-type MMR gene allele had occurred through point mutation or promoter hypermethylation, frequent somatic deletions at the region of the MMR gene locus, perhaps targeting other relevant cancer genes, could quite commonly lead to loss of the mutant allele. To test this hypothesis, we studied a population-based series of 25 fresh-frozen HNPCC tumors with a germline mutation in MLH1 or MSH2 for LOH. Fourteen of the 25 tumors (56%) showed LOH at the respective locus, and all 14 losses targeted the wild-type allele (P=0.00006). These results strongly support the traditional two-hit model of HNPCC gene inactivation.Oncogene (2007) 26, 2513–2517. doi:10.1038/sj.onc.1210038; published online 9 October 2006 [ABSTRACT FROM AUTHOR]

Prostate cancer (PCa) is the most commonly diagnosed non-cutaneous cancer in male subjects in Western countries. The widespread use of prostate-specific antigen (PSA) has increased the detection of this cancer form in earlier stages. Moreover, it has increased the need for new diagnostic procedures to be developed for patient stratification based on risk of progression. We analysed laser-microdissected prostate tumour tissue from 43 patients with histologically verified PCa, using the new high-resolution Affymetrix Mapping 50K single-nucleotide polymorphism array. The results showed six major loss of heterozygosity regions at chromosomes 6q14–16, 8p23–11, 10q23, 13q13–21 and 16q21–24 and a novel region at chromosome 21q22.2, all of which reveal concomitant copy number loss. Tumour development was further characterised by numerous novel genomic regions almost exclusively showing copy number loss. However, tumour progression towards a metastatic stage, as well as poor differentiation, was identified by specific patterns of copy number gains of genomic regions located at chromosomes 8q, 1q, 3q and 7q. Androgen ablation therapy was further characterised by copy gain at chromosomes 2p and 10q. In conclusion, patterns of allelic imbalance were discovered in PCa, consisting allelic loss as an early event in tumour development, and distinct patterns of allelic amplification related to tumour progression and poor differentiation.British Journal of Cancer (2007) 96, 499–506. doi:10.1038/sj.bjc.6603476 www.bjcancer.com Published online 23 January 2007 [ABSTRACT FROM AUTHOR]

The cytotoxic activity of T cells selects the outgrowth of tumor cells that escape from immune surveillance by different strategies. The different mechanisms that interfere with immune recognition and limit vaccination efficiency are still poorly understood. We analysed six cell lines established from different metastases of melanoma patient UKRV-Mel-20 for specific characteristics known to have an impact on the tumor-T cell interaction: (1) alterations in the HLA class I phenotype, (2) expression of Fas/CD95, and (3) expression of specific cytokines and chemokines. One of the cell lines, UKRV-Mel-20f, exhibited an HLA class I haplotype loss and just this cell line was also characterised by the expression of Fas/CD95 and of relatively high levels of proinflammatory chemokines suggesting that the cytotoxic activity of tumor-infiltrating T cells might have selected the outgrowth of this tumor cell variant. All other cell lines analysed showed no alterations in HLA class I expression, but, in contrast to UKRV-Mel-20f, expressed much lower levels of Fas/CD95 and of proinflammatory chemokines and some of them produced high levels of immunosuppressive TGF-β1. These results suggest that in patient UKRV-Mel-20, tumor cells interfere with T cell recognition by different strategies which might partially explain why this patient did not have a clinical response to an autologous tumor cell vaccine. [ABSTRACT FROM AUTHOR]

Smad4 protein, whose gene is coded at chromosome 18q21.1, is an important tumour suppressor that mediates transforming growth factor-beta. It has been reported that inactivation of the Smad4 gene and allelic loss of chromosome 18q correlate with liver metastasis and poorer prognosis in colorectal cancers. Utilising a recently developed method of immunohistochemical staining for Smad4 protein, we focused on the specific impact of Smad4 protein expression on liver metastasis in colorectal cancer. We also evaluated the association between chromosome18q deletion and liver metastasis. We selected 20 colorectal cancers with liver metastasis for the experimental group, and 20 cases without liver metastasis for the control. In order to exclude the influence of lymph node metastasis, all cases were lymph node negative. In addition, the two groups were matched for tumour depth, tumour differentiation and tumour location. We compared the expression level of Smad4 protein immunohistochemically in these 20 matched pairs. We also compared the loss of heterozygosity status at chromosome 18q in these 20 matched pairs. Immunohistochemical staining revealed a significant difference (P=0.024) in the level of Smad4 protein between the two groups. We also observed a significantly different (P=0.0054) ratio of allelic deletion at chromosome 18q21. Smad4 protein expression level and allelic loss at 18q21 are associated with the process of liver metastasis in colorectal cancers evaluated when excluding clinical and pathological features except for liver metastasis.British Journal of Cancer (2006) 95, 1562–1567. doi:10.1038/sj.bjc.6603460 www.bjcancer.com Published online 7 November 2006 [ABSTRACT FROM AUTHOR]

We have shown previously that stromal genetic alteration may make a greater contribution to early genesis of ulcerative colitis-associated tumors than sporadic colon cancers. We assessed whether similar differences in genetic alteration might exist between squamous cell carcinomas (SCCs) and Barrett's adenocarcinomas (BACs) of the esophagus. We investigated epithelial and stromal genetic instability with five National Cancer Institute standard (NCI), four chromosome 17 (Chr. 17), and six tumor suppressor gene (TSG) microsatellite markers in 26 SCC and 12 BAC cases and in 11 normal controls, using a novel combination of microdissection, polymerase chain reaction, and GeneScan. Frequency of epithelial loss of heterozygosity (LOH) increased in the order background mucosa, to precursor lesions, to tumors with both types of carcinoma, especially for the Chr. 17 and TSG markers, while stromal LOH was relatively high but consistent from background mucosa to carcinoma. Epithelial LOH of D17S796 demonstrated a significantly higher frequency in SCCs than in BACs, without significant variation in p53 overexpression. The frequency of microsatellite instability (MSI) showed constant high levels in both epithelium and stroma of background, dysplasia, and carcinomas in the SCC series, and rather low frequencies in the BAC series. Although epithelial hMLH1 and hMSH2 expression decreased with tumor progression, no correlation was found with the individual MSI status. Although epithelial LOH exists similarly in both lesion types, whereas epithelial and stromal MSI may occur in a relatively early phase of SCC development, stromal MSI is rare in BACs, strongly suggesting differences in tumorigenesis between the two types. [ABSTRACT FROM AUTHOR]

Copyright of Der Urologe A is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Allelic imbalance (AI), which represents certain chromosomal gains or losses, has been described in hepatocellular carcinoma (HCC), but the significance of AI analysis in focal nodular hyperplasia (FNH) has not been fully clarified. We hypothesized, therefore, that comprehensive allelotyping of FNH could be a useful tool for differentiating FNH from HCC. A 27-year-old man was admitted to the hospital because of general fatigue. A computed tomography (CT) scan disclosed a hepatic nodule 8 cm in diameter. No definite diagnosis was made after imaging or by biopsy before surgery. Macroscopically and microscopically, the surgical specimen showed typical features of FNH. Comprehensive microsatellite analysis was carried out with 382 microsatellite markers distributed throughout all chromosomes. To detect AI effectively, the cutoff value of the AI index was set at 0.70. Among the 382 microsatellite markers, 212 loci were informative, but no AI was detected. The absence of gross chromosomal alterations strongly suggested that the large nodule was FNH rather than HCC, in terms of its genetic background. The patient's subsequent clinical course revealed the nodule to be benign. The results suggest that this genome-wide microsatellite analysis is a useful tool for the differential diagnosis of non-neoplastic liver nodules from HCC. [ABSTRACT FROM AUTHOR]

Inactivation of one Ptc1 allele predisposes humans and mice to spontaneous medulloblastoma development, and irradiation of newborn Ptc1 heterozygous mice results in dramatic increase of medulloblastoma incidence. While a role for loss of wild-type (wt) Ptc1 (LOH) in radiation-induced medulloblastomas from Ptc1neo67/+ mice is well established, the importance of this event in spontaneous medulloblastomas is still unclear. Here, we demonstrate that biallelic Ptc1 loss plays a crucial role in spontaneous medulloblastomas, as shown by high rate of wt Ptc1 loss in spontaneous tumors. In addition, remarkable differences in chromosomal events involving the Ptc1 locus in spontaneous and radiation-induced medulloblastomas suggest distinct mechanisms for Ptc1 loss. To assess when, during tumorigenesis, Ptc1 loss occurs, we characterized cerebellar abnormalities that precede tumor appearance in Ptc1neo67/+ mice. We show that inactivation of only one copy of Ptc1 is sufficient to give rise to abnormal cerebellar proliferations with different degree of altered cell morphology, but lacking potential to progress to neoplasia. Furthermore, we identify biallelic Ptc1 loss as the event causally related to the transition from the preneoplastic stage to full blown medulloblastoma. These results underscore the utility of the Ptc1neo67/+ mouse model for studies on the mechanisms of medulloblastoma and for development of new therapeutic strategies.Oncogene (2006) 25, 5575–5580. doi:10.1038/sj.onc.1209544; published online 24 April 2006 [ABSTRACT FROM AUTHOR]

Deletions of chromosome 6q have been reported in several hematological malignancies, but data are not conclusive regarding their biological and prognostic impact. Therefore, we focused on pediatric patients diagnosed with T-cell lymphoblastic lymphoma (T-LBL) treated uniformly according to the NHL-BFM95 protocol. We used loss-of-heterozygosity (LOH) analysis of 25 microsatellite markers located on chromosome 6q14–q24. Fragment-length analysis was performed on ABI-PRISM3100 Genetic-Analyzer. Eligibility criterion was 3 informative markers. Between April 1995 and March 2003, 185 T-LBL patients were treated according to the NHL-BFM95 protocol. Five-year event-free (EFS) and disease-free survival (DFS) were 79±3 and 87±3% (median follow-up 4.7 [1.2–10.1] years). Sixty-one patients were evaluable for LOH analysis, including 18 out of 23 patients with relapse. EFS and DFS were 67±6 and 69±6% for these 61 patients. Testing of 853 markers in the 61 patients identified the presence of LOH in 19 patients (31%): 13 of the 18 relapse patients and five of the 41 in complete remission (odds ratio 18.7, 95% confidence interval 4.7–75.3). One LOH-positive patient died from treatment-related toxicity. We conclude that LOH on chromosome 6q14–q24 may have conferred a high risk of relapse on our group of children with T-LBL treated according to the NHL-BFM95 protocol.Leukemia (2006) 20, 1422–1429. doi:10.1038/sj.leu.2404275; published online 1 June 2006 [ABSTRACT FROM AUTHOR]

Alterations in HLA class I antigen expression have been frequently described in different epithelial tumors and are thought to favor tumor immune escape from T lymphocyte recognition. Multiple molecular mechanisms are responsible for these altered HLA class I tumor phenotypes. Some are structural defects that produce unresponsiveness to treatment with interferons. Others include alterations in regulatory mechanisms that can be switched on by treatment of tumor cells with different cytokines. One important mechanism belonging to the first group is loss of heterozygosity (LOH) at chromosome region 6p21.3, which can lead to HLA haplotype loss. In this investigation, the frequency of LOH at 6p21 chromosome region was studied in 69 bladder carcinomas. Short tandem repeat analysis showed that 35% of cases had LOH in this chromosome region. By considering these results together with immunohistological findings previously published by our group, we identified a distribution pattern of HLA class I altered phenotypes in bladder cancer. The most frequently altered phenotype in bladder carcinomas was total loss of HLA class I expression (17 cases, 25%), followed by phenotype II associated with HLA haplotype loss (12 cases, 17.5%), and HLA allelic loss (ten cases, 14.5%). Nine cases (13%) were classified as having a compound phenotype, five cases (7%) as having HLA locus loss, and in 16 cases (23%) no alteration in HLA expression was detected. An important conclusion of this report is that a combination of different molecular and immunohistological techniques is required to precisely define which HLA alleles are lost during tumor progression and to characterize the underlying mechanisms of these losses. These studies should be performed when a cancer patient is to be included in an immunotherapy protocol that aims to stimulate different immune effector mechanisms. [ABSTRACT FROM AUTHOR]

hMLH1 and hMSH2 can be considered tumor suppressor genes, as both alleles must be inactivated in order to lose the mismatch repair (MMR) function. In this regard, it has been proposed that LOH at MMR loci is a common Knudson's second-hit mechanism in HNPCC patients. However, experimental evidence supporting this view is scarcely found in the literature. We have performed a comprehensive analysis of LOH in 45 HNPCC tumors carrying a germline alteration in MMR loci. Overall, we have detected LOH at MMR loci in 56% of the cases. However, up to 40% of the LOH events targeted the mutant allele, arguing against a second-hit role in these tumors. Interestingly, the age at diagnosis was significantly older in these patients. To explain this and previous data, we propose a dual role for LOH at MMR loci in HNPCC.Oncogene (2006) 25, 2124–2130. doi:10.1038/sj.onc.1209233; published online 14 November 2005 [ABSTRACT FROM AUTHOR]

The Smad4+/E6sad mouse carries a null mutation in the endogenous Smad4 gene resulting in serrated adenomas and mixed polyposis of the upper gastrointestinal (GI) tract with 100% penetrance. Here, we show by loss of heterozygosity (LOH) analysis and immunohistochemistry (IHC) that, although the majority of the tumors appear at 9 months of age, somatic loss of the wild-type Smad4 allele occurs only at later stages of tumor progression. Hence, haploinsufficiency underlies Smad4-driven tumor initiation in the GI tract. As both the Apc and Smad4 tumor suppressor genes map to mouse chromosome 18, we have bred Smad4+/E6sad with the Apc+/1638N model to generate two distinct compound heterozygous lines carrying both mutations either in cis (CAS) or in trans (TAS). Strikingly, both models show increased tumor multiplicities when compared with the single mutant littermates, although CAS mice are more severely affected and became moribund at only 5–6 weeks of age. Phenotypic and molecular analyses indicate that Smad4 haploinsufficiency is sufficient to significantly affect tumor initiation and progression both prior to and upon loss of Apc function. Moreover, complete loss of Smad4 strongly enhances Apc-driven tumor formation.Oncogene (2006) 25, 1841–1851. doi:10.1038/sj.onc.1209226; published online 14 November 2005 [ABSTRACT FROM AUTHOR]

Hemizygous Ptc1 mice have many features of Gorlin syndrome, including predisposition to medulloblastoma development. Ionizing radiation synergize with Ptc1 mutation to induce medulloblastoma only in neonatally exposed mice. To explore the mechanisms underlying age-dependent susceptibility, we irradiated Ptcneo67/+ mice at postnatal day 1 (P1) or 10 (P10). We observed a dramatic difference in medulloblastoma incidence, which ranged from 81% in the cerebellum irradiated at P1 to 3% in the cerebellum irradiated at P10. A stricking difference was also detected in the frequency of cerebellar preneoplastic lesions (100 versus 14%). Our data also show significantly lower induction of apoptosis in the cerebellum of medulloblastoma-susceptible (P1) compared to -resistant (P10) mice, strongly suggesting that medulloblastoma formation in Ptc1 mutants may be associated with resistance to radiation-induced cell killing. Furthermore, in marked contrast with P10 mice, cerebellum at P1 displays substantially increased activation of the cell survival-promoting Akt/Pkb protein, and markedly decreased p53 levels in response to radiation-induced genotoxic stress. Overall, these results show that developing cerebellar granule neuron precursors' (CGNPs) radiosensitivity to radiation-induced cell death increases with progressing development and inversely correlates with their ability to neoplastically transform.Oncogene (2006) 25, 1165–1173. doi:10.1038/sj.onc.1209032; published online 9 January 2006 [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to understand whether there is any association between specific deleted regions in chromosome 11 (chr.11) and alteration (amplification/rearrangement) of Bcl-1/Cyclin D1 locus, located at 11q13, in uterine cervical carcinoma (CA-CX). Methods: The deletion mapping of chr.11 was studied using 17 highly polymorphic microsatellite markers in 65 primary uterine cervical lesions. The Bcl-1/Cyclin D1 alterations were analyzed by Southern blot and/or polymerase chain reaction (PCR) method in respective cervical lesions. Results: Chr.11 deletion was found to be significantly associated with progression of CA-CX. High frequency (48-65%) of deletion was found in 11p15.5 (D1), 11q22.3-23.1(D2), and 11q23.3- 24.1(D3) regions and significant association was seen among deletions in D2 and D3 regions. Bcl-1/Cyclin D1 locus alteration was observed in overall 27% cervical lesions. Co-amplification of Bcl-1/Cyclin D1 locus was seen in 10% samples. However, no association was found between the deleted regions and Bcl-1/Cyclin D1 locus alterations. Conclusions: Our study suggests that there is no co-operativity between the deleted regions (D1- D3) in chr.11 and Bcl-1/Cyclin D1 alterations, but these alterations may provide cumulative effect in progression of the tumor. The D1-D3 regions may harbor candidate tumor suppressor gene(s) (TSGs) associated with the development of CA-CX. [ABSTRACT FROM AUTHOR]

Various genomic technologies have been applied to address crucial problems in cancer biology, because cancer develops through the accumulation of various genetic alterations. Of these, gene expression profiling analysis using microarray technology has been widely applied not only to classify cancers at molecular levels, but also to identify novel molecular targets for therapeutics and/or diagnostics. To gain molecular understanding of gastric carcinogenesis, progression, and diversity, we analyzed primary advanced gastric cancer and noncancerous gastric tissues by high-density oligonucleotide microarray. Genes differentially expressed between cancer and noncancerous tissues were identified. In cancer tissues, genes related to cell cycle, growth factor, cell motility, cell adhesion, and matrix remodeling were highly expressed, whereas those related to gastrointestinal-specific function and immune response were rather downregulated. These results provide not only a new molecular basis for understanding biological properties of gastric cancer but also useful resources for future development of therapeutic and diagnostic biomarkers for gastric cancer. Several microarray studies have been published since and have been compared for validation in meta-analysis. As integration of transcriptome information with other biological data is crucial to interpret gene expression data, we have applied oligonucleotide microarray technology to assess allelic gene dosage at 10000 polymorphic loci, namely with an average interval of 200 kb. Using a newly developed algorithm, genome imbalance map. loss of heterozygosity (LOH) status can be determined simultaneously. Besides several loci with genomic amplification, we also identified a homozygously deleted chromosomal region in 7q, where frequent chromosomal instability was observed. Finally, we are currently developing novel biomarkers for gastroenterological cancers. Glypican 3 is detected at high levels in serum of hepatocellular carcinoma patients and could be a potential target for antibody therapy. [ABSTRACT FROM AUTHOR]

A considerable fraction of families with HNPCC shows no germline mismatch repair (MMR) gene mutations. We previously detected‘hidden’MMR gene defects in 42%of such families, leaving the remaining 58%‘truly’mutation negative. Here, we characterized 50 colorectal carcinomas and five adenomas arising in HNPCC families; 24 truly MMR gene mutation negative and 31 MMR gene mutation positive. Among 31 tumors from MMR gene mutation positive families, 25 (81%) had active Wnt signaling as indicated by aberrantß-catenin localization with or without CTNNB1 mutations, compared to only 7/18 tumors from MMR gene mutation negative families (39%; P=0.005). CGH studies revealed stable profiles in 9/16 (56%) of MMR gene mutation negative tumors, which was significantly associated with membranousß-catenin (P=0.005). Tumors with membranousß-catenin from the MMR gene mutation negative group also showed low frequency of TP53 mutations compared to those with nuclearß-catenin. Thus, a majority of the MMR gene mutation negative cases exhibited a novel molecular pattern characterized by the paucity of changes in common pathways to colorectal carcinogenesis. This feature distinguishes the MMR gene mutation negative families from both HNPCC families linked to MMR defects and sporadic cases, suggesting the involvement of novel predisposition genes and pathways in such families.Oncogene (2005) 24, 1542-1551. doi:10.1038/sj.onc.1208387 Published online 17 January 2005 [ABSTRACT FROM AUTHOR]

Malignant transformation of cells is frequently associated with abnormalities in human leukocyte antigen (HLA) expression. MHC class I loss or down-regulation in cancer cells is a major immune escape route used by a large variety of human tumours to evade antitumour immune responses mediated by cytotoxic T lymphocytes. The goal of our study was to explore HLA genotyping and phenotyping in a variety of melanoma tumour cell lines. A total of 91 melanoma cell lines were characterised for HLA class I and II genotype. In addition, 61 out of the 91 cell lines were also analysed for HLA class I and II cell surface molecule expression by flow cytometry. Unexpectedly, we found that 19.7% of the melanoma cell lines were homozygous for HLA class I genotypes, sometimes associated with HLA class II homozygosity (8.79%) and sometimes not (10.98%). The frequency of homozygosity was significantly higher compared with the control groups (1.6%). To identify the reasons underlying the high frequency of HLA homozygosity we searched for genomic deletions using eight pairs of highly polymorphic microsatellite markers covering the entire extended HLA complex on the short arm of chromosome 6. Our results were compatible with hemizygous deletions and suggest that loss of heterozygosity on chromosome arm 6p is a common feature in melanoma cell lines. In fact, although autologous normal DNA from the patients was not available and could not be tested, the retention in some cases of heterozygosity for a number of microsatellite markers would indicate a hemizygous deletion. In the rest of the cases, markers at 6p and 6q showed a single allele pattern indicating the probable loss of part or the whole of chromosome 6. These results led us to conclude that loss of heterozygosity in chromosome 6 is nonrandom and is possibly an immunologically relevant event in human malignant melanoma. Other well-established altered HLA class I phenotypes were also detected by flow cytometry that correspond to HLA class I total loss and HLA-ABC and/or specific HLA-B locus down-regulation. [ABSTRACT FROM AUTHOR]

We investigated whether genetic lesions such as loss of heterozygosity (LOH) are detected in prostatic cells obtained by prostatic massage during early diagnosis of prostate cancer (CaP) and discussed their clinical relevance. Blood and first urine voided after prostatic massage were collected in 99 patients with total prostate-specific antigen (PSA) between 4 and 10 ng ml(-1), prior to prostate biopsies. Presence of prostatic cells was confirmed by quantitative RT-PCR analysis of PSA mRNA. Genomic DNA was analysed for LOH on six chromosomal regions. One or more allelic deletions were found in prostatic fluid from 57 patients analysed, of whom 33 (58%) had CaP. Sensitivity and specificity of LOH detection and PSA free to total ratio <15% for positive biopsy were respectively 86.7 and 44% (P=0.002) for LOH, and 55 and 74% (P=0.006) for PSA ratio <15%. Analysis of LOH obtained from prostatic tumours revealed similar patterns compared to prostatic fluid cells in 86% of cases, confirming its accuracy. The presence of LOH of urinary prostatic cells obtained after prostatic massage is significantly associated with CaP on biopsy and may potentially help to identify a set of patients who are candidates for further prostate biopsies. [ABSTRACT FROM AUTHOR]

The expression of PINX1, a possible telomerase inhibitor and a putative tumor suppressor, has not been studied in human cancers, including gastric cancer (GC). We examined expression of PINX1 by quantitative reverse transcription (RT)-PCR in 73 cases of GC, and 45 of these cases were further studied for loss of heterozygosity (LOH) by PCR with microsatellite marker D8S277. Reduced expression (tumor vs normal ratio<0.5) of PINX1 was detected in 50 (68.5%) of 73 cases of GC. GC tissues with reduced expression of PINX1 showed significantly higher telomerase activities as measured by telomeric repeat amplification protocol than those with normal expression of PINX1 (P=0.031). LOH of PINX1 locus was detected in 15 (33.3%) of 45 cases of GC and was correlated significantly with reduced expression of PINX1 (P=0.031). Expression of PINX1 in a GC cell line, MKN-74, was induced by treatment with trichostatin A (TSA) or nicotinamide (NAM). Chromatin immunoprecipitation assay of MKN-74 cells revealed that acetylation of histone H4 in the 5'untranslated region (UTR) of PINX1 was enhanced by treatment with TSA or NAM, whereas acetylation of histone H3 was not changed by TSA or NAM. In addition, TSA or NAM treatment led to inhibition of telomerase activity in MKN-74 cells. These results indicate that LOH of PINX1 locus and hypoacetylation of histone H4 in the 5'UTR of PINX1 are associated with reduced expression of PINX1 in GC.Oncogene (2005) 24, 157-164. doi:10.1038/sj.onc.1207832 [ABSTRACT FROM AUTHOR]