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Objective To determine chromosome and gene alterations in ectopic endometrial (EM) tissue which may be implicated in the clinical course or the progression of endometriosis and to review the literature concerning the cytogenetic findings of women with endometriosis. Study design 15 women who underwent laparoscopic endometriosis surgery at the Athens Genesis Clinic were enrolled in the study. Ectopic endometrial tissue was surgically removed and further analyzed by conventional and molecular cytogenetic techniques. Fluoresent in situ hibridization (FISH) with probes for p53, ATM, MYC, MLL1 and IGH genes, the centromeres of chromosomes 7 and 8 and 7q22/7q31 chromosomal regions was carried out. Results Karyotypic analysis revealed no clonal chromosomal abnormalities. However, an increased frequency of polyploidy (55.6%) and sporadic chromosomal abnormalities (40.0%) concerning chromosomes 9, 11, 17 and X were noticed involving mainly deletions, trisomies or monosomies. FISH analysis showed IGH gene rearrangements in 54% of the EM cases and MLL gene rearrangements in 73% of the examined samples. Normal hybridization patterns were observed for p53, ATM and MYC. The increased frequency of polyploidy shown by conventional karyotyping was also confirmed by FISH. Conclusion Polyploidy, sporadic chromosomal abnormalities, as well as IGH and MLL gene rearrangements, may provoke genetic instability and play a potential role in the development of endometriosis. IGH and MLL gene rearrangements indicate a genetic relation between endometriosis and carcinogenesis. Confirmation of the above gene rearrangements in a large series of women may allow the determination of their possible involvement in the pathogenesis of this complex disease and their possible contribution in the early identification of women in danger for malignant transformation.

Chromosomal abnormalities are often detected in women with reproductive problems. This study aimed to investigate the presence and type of chromosomal aberrations in peripheral blood of women undergoing in vitro fertilization (IVF) and their possible association with advanced maternal age (AMA). A total of 1,837 women undergoing IVF between 2016 and 2019 were enrolled in the study. Women were further divided in AMA (≥35 years) and younger women (p < 0.05). Women of AMA exhibited X chromosome mosaicism with a frequency of 16.1%, and mosaic karyotypes with 2 and 3 aneuploid cell lines were more frequently detected. X chromosome mosaicism is the most common karyotypic aberration in women undergoing IVF and has 6-fold increased incidence in AMA women compared to younger ones. The present study verifies previous observations that low-level peripheral blood X chromosome mosaicism and the number of aneuploid cell lines observed in women of AMA could be an indication of aneuploidy and poor quality of oocytes contributing to infertility.

Acute myeloid leukemia (AML) is an aggressive cancer that progresses rapidly with a poor prognosis. Cytogenetic analysis provides the most accurate determination of diagnosis and prognosis however, about 42-48% of AML patients have a cytogenetically normal karyotype. Genetic analysis can provide further information and the identification of new mutations could result in improved risk stratification, prognosis and better understanding of the mechanisms of AML leukaemogenesis. In this study, we analyzed genetic alterations in 16 human AML cases by Haloplex sequencing with confirmation of two previously unreported mutations in the genes DNMT3A and RUNX1 by Sanger sequencing or pyrosequencing. The two novel mutations consist of two frameshift mutations identified in two different AML patients and reported as deleterious by bioinformatic analysis. These mutations confirm the exclusion and co-occurrence of specific gene mutation patterns in AML and may provide further information for patient diagnosis and prognosis.

Background/aim To determine the incidence of X chromosome mosaicism in women undergoing in vitro fertilization (IVF) treatment and present preimplantation genetic testing for aneuploidy (PGT-A) outcome of this group. Patients and methods A total of 1,058 women undergoing IVF and 154 women with no fertility problems were enrolled in the study. Karyotyping from peripheral blood lymphocytes was performed by conventional cytogenetics. Twenty-nine women with X mosaicism underwent PGT-A by array-comparative genomic hybridization from embryos at the blastocyst stage. Results and conclusion Out of 1,058 women undergoing IVF, 166 (15.7%) had an abnormal karyotype. The most common finding (14.6%) was X chromosome mosaicism. Its frequency was higher in women >35 years old and reached 46.1% in those >45 years of age. PGT-A results of 130 blastocysts tested showed that 29/117 (24.8%) were euploid; 17/29 (60%) were transferred and 10/17 (70%) were successfully implanted, indicating that PGT-A may be an option for women with low-level X chromosome mosaicism undergoing IVF in order to improve the likelihood of a successful pregnancy outcome.

Background/aim PON1 gene has an executive role in antioxidant defense, protecting cells from genotoxic factors. Q192R and L55M PON1 polymorphisms reduce catalytic activity of the encoded protein. These polymorphisms were studied in 300 chronic lymphocytic leukemia (CLL) patients and 106 healthy donors. They were also associated with patients' cytogenetic findings, to investigate their possible implication in CLL pathogenesis. Materials and methods SNP genotyping was performed using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay. Karyotypic analysis was also performed by chromosome G-banding analysis and fluorescence in situ hybridization. Results Genotypic and allelic distribution of Q192R polymorphism showed a statistically significant higher frequency of mutant genotypes and mutant alleles in patients compared to controls. The same observation was noted in patients with abnormal karyotypes and those carrying abn14q32 and del(6q). A statistically increased frequency for the mutant allele was also revealed in patients with del(11q). On the contrary, L55M polymorphism showed a similar distribution between patients and controls. Conclusion Q192R polymorphism plays a role in CLL predisposition and the formation of specific chromosomal aberrations.

Mutations of ASXL1 are early events in acute myeloid leukemia (AML) leukemogenesis and have been associated with unfavorable prognosis. In this study, we investigated the type and frequency of ASXL1 mutations in a large cohort of patients with de novo or secondary AML (s-AML) and looked for correlations with cytogenetic findings and disease features. ASXL1 mutations were associated with older age, s-AML and higher peripheral leukocytosis. We observed more frequent co-occurrence of ASXL1 mutations with trisomy 8 and chromosome 11 aberrations but a negative correlation with myelodysplastic syndromes (MDS)-related cytogenetic abnormalities, especially -5/del(5q) and -7/del(7q). ASXL1 mutations were also found in other genetically defined AML subgroups such as those with t(9;22), inv(3)/t(3;3), t(8;21) or t(15;17); however, none of our inv(16) cases carried ASXL1 mutations. We detected two previously unreported ASXL1 mutations, p.IIe593Val and p.Cys688Tyr. Our findings suggest that ASXL1 mutations tend to cluster with specific clinical and cytogenetic profiles of AML patients.

Chronic lymphocytic leukemia (CLL) is the most common type of leukemia in adults and is characterized by the presence of specific cytogenetic abnormalities. CLL research has been focused on epigenetic processes like gene promoter methylation of CpG islands. In the present study, the methylation status of the RAD21 gene is studied and associated with cytogenetic findings in CLL patients in order to investigate its possible implication in CLL pathogenesis and the formation of CLL chromosomal abnormalities.

Genome‐wide studies in tumor cells have indicated that chromatin‐modifying proteins are commonly mutated in human cancers. The lysine‐specific methyltransferase 2C (KMT2C/MLL3) is a putative tumor suppressor in several epithelia and in myeloid cells. Here, we show that downregulation of KMT2C in bladder cancer cells leads to extensive changes in the epigenetic status and the expression of DNA damage response and DNA repair genes. More specifically, cells with low KMT2C activity are deficient in homologous recombination‐mediated double‐strand break DNA repair. Consequently, these cells suffer from substantially higher endogenous DNA damage and genomic instability. Finally, these cells seem to rely heavily on PARP1/2 for DNA repair, and treatment with the PARP1/2 inhibitor olaparib leads to synthetic lethality, suggesting that cancer cells with low KMT2C expression are attractive targets for therapies with PARP1/2 inhibitors.

Objectives In bronchopulmonary dysplasia (BPD), direct exposure to oxygen therapy can damage the pulmonary epithelium via oxidative stress. The NAD(P)H:quinone oxidoreductase 1 (NQO1) enzyme detoxifies genotoxic products of oxidative stress. The corresponding gene is subject to an inactivating single-nucleotide polymorphism (C 609 T), which reduces detoxifying ability. The aim of this study was to investigate whether the C 609 T NQO1 inborn gene polymorphism is associated with an increased risk of BPD. Study Design Peripheral blood samples from 119 premature neonates ≤ 32 weeks of gestational age (42 BPD and 77 non-BPD) were used for DNA extraction. NQO1 genotyping was performed using the polymerase chain reaction-restriction fragment length polymorphism method. Results A significantly higher frequency of the NQO1 polymorphism was observed in BPD neonates compared with neonates without BPD. All neonates with ≤ 1,000 g birth weight who carried the mutant allele in heterozygous or homozygous state developed BPD. None of the BPD nonaffected group neonates with ≤ 1,000 g birth weight carried the NQO1 polymorphism. Conclusion The higher incidence of NQO1 mutants among BPD neonates as well as the presence of the mutant allele in all neonates with ≤ 1,000 g who developed BPD provided the first evidence for a possible pathogenetic role of the C 609 T polymorphism in BPD susceptibility due to the reduction or loss of NQO1 enzymatic activity.

Acute myeloid leukemia (AML) is a clinically and genetically heterogeneous disease and the most common acute leukemia in adults. Many genotoxic factors have been accused for AML development but onl...

Chronic lymphocytic leukemia (CLL) is the most common type of leukemia in adults and is characterized by the presence of specific cytogenetic abnormalities. CLL research has been focused on epigenetic processes like gene promoter methylation of CpG islands. In the present study, the methylation status of the RAD21 gene is studied and associated with cytogenetic findings in CLL patients in order to investigate its possible implication in CLL pathogenesis and the formation of CLL chromosomal abnormalities.

This study aimed to investigate whether occupational and environmental exposures, lifestyle, family, and medical history are associated with chronic lymphocytic leukemia (CLL) risk and its chromosomal abnormalities. The study included 138 CLL cases and 141 age- and sex-matched controls. Information data were collected through in-person interviews from cases and controls. Cytogenetic analysis was performed on CLL bone marrow cells. Positive associations were found between CLL and cancer family history, smoking, pneumonia, and exposure to petroleum, metals, pesticides/chemical fertilizers, detergents, and medical radiation. Chromosome deletions of 11q and 13q were more frequent in patients exposed to pesticides and rubber, respectively. This study investigated for the first time specific risk factors in relation to CLL aberrations and presented positive correlations. Moreover, it indicates the possible involvement of specific occupational and lifestyle risk factors in the onset of CLL.

Objectives Antioxidant response plays a key role in bronchopulmonary dysplasia (BPD) pathogenesis. The glutathione-S-tranferases pi 1 (GSTP1) and cytochrome P450 (CYP) detoxification enzymes protect cells from oxidative damage. The aim of the study was to investigate whether the A313G GSTP1 and G516T CYP2B6 inactivating polymorphisms could be associated with BPD susceptibility. Study Design To test this hypothesis, we conducted a case–control study enrolled 138 premature neonates ≤32 weeks of gestational age; of the 138, 46 developed BPD and 92 did not develop BPD. Genomic deoxyribonucleic acid was extracted from neonates' peripheral blood and was used as template for GSTP1 and CYP2B6 genotyping using the real-time polymerase chain reaction method. Results Our report provides evidence for a possible pathogenetic role of the G516T CYP2B6 polymorphism in BPD susceptibility. Although no differences in the frequencies of the GSTP1 variant genotypes were noticed between premature neonates who developed BPD and neonates who did not develop BPD, a significantly higher frequency of the GSTP1 polymorphism was observed in extremely low birth weight infants. Despite the small sample size, it is very interesting the fact that all neonates ≤1,000 g carrying the homozygous mutant GSTP1 genotype developed BPD. Conclusion Our results underscore the significance of both CYP2B6 and GSTP1 polymorphisms in modulating the risk of BPD.

Newer cytogenetic scoring systems for myelodysplastic syndromes (MDSs), like cytogenetic stratification of the revised international prognostic scoring system (IPSS-R) or monosomal karyotype, may also improve outcome prediction after hematopoietic SCT (HCT). We compared the prognostic value of specific cytogenetic abnormalities, IPSS-R karyotype and monosomal karyotype for HCT outcome in 98 patients with MDS and AML post MDS. Higher-risk IPSS-R karyotype, 3q21q26 and transformation to AML before HCT were associated with increased cumulative incidence of relapse (CIR), whereas OS was adversely influenced by del 5q/-5, abnormalities of chromosomes 11 and 17 and cytogenetic IPSS-R very poor category. Karyotype with ⩽2 abnormalities and no abnormalities of chromosomes 3, 5, 7, 11 and 17 was an independent prognostic factor of lower CIR (hazard ratio (HR)=0.2, P=0.01) and longer OS (HR=0.5, P=0.03). In conclusion, some specific cytogenetic abnormalities and high cytogenetic complexity, as reflected by IPSS-R very poor karyotype, rather than monosomal karyotype, were associated with higher CIR and shorter OS after HCT. Conversely, results were encouraging in patients lacking those abnormalities, who may be very good candidates for HCT.

Acute leukaemia of ambiguous lineage (ALAL) is a rare complex entity with heterogeneous clinical, immunophenotypic, cytogenetic and molecular genetic features and adverse outcome. According to World Health Organization 2008 classification, ALAL encompasses those leukaemias that show no clear evidence of differentiation along a single lineage. The rarity of ALAL and the lack of uniform diagnostic criteria have made it difficult to establish its cytogenetic features, although cytogenetic analysis reveals clonal chromosomal abnormalities in 59-91% of patients. This article focuses on the significance of cytogenetic analysis in ALAL supporting the importance of cytogenetic analysis in the pathogenesis, diagnosis, prognosis, follow up and treatment selection of ALAL. It reviews in detail the types of chromosomal aberrations, their molecular background, their correlation with immunophenotype and age distribution and their prognostic relevance. It also summarizes some novel chromosome aberrations that have been observed only once. Furthermore, it highlights the ongoing and future research on ALAL in the field of cytogenetics.

The NQO1 C(609)T germline polymorphism resulting in a lowering of enzyme activity may confer susceptibility to MDS. To assess this association, we performed a case-control study including 330 Greek patients with de novo MDS and 416 healthy donors, using a Real-Time PCR genotyping method. Focusing on cytogenetic aberrations most commonly found in MDS, we retrospectively genotyped 566 MDS/AML patients carrying -5/del(5q), -7/del(7q), +8, del(20q) and -Y. The case-control analysis revealed no differences in NQO1 genotype distribution. Interestingly, a 6-fold increased frequency of the homozygous variant genotype was observed among patients with isolated trisomy 8 (p

Models for the pathogenesis of myelodysplastic syndrome (MDS) imply the role of individual genetic variations in genes involved in detoxification mechanisms. GSTP1 enzyme plays a key role in the biotransformation of a variety of carcinogens. The corresponding gene is subject to a single nucleotide polymorphism (A(313)G) leading to abolished enzyme activity. In order to evaluate whether the GSTP1 polymorphism influences MDS susceptibility, we conducted a case-control study comprising 310 de novo patients and 370 healthy controls using a real-time polymerase chain reaction (PCR) genotyping method. The GSTP1 gene status was also evaluated in relation to patients' characteristics and chromosomal abnormalities. A significantly higher incidence of the GSTP1 variant genotypes was observed in patients with MDS compared to controls (p0.0001). The results revealed increased frequencies of heterozygotes in patients younger than 60 years old and of homozygotes G/G in older patients (p = 0.007). Our results provide evidence for a pathogenetic role of the GSTP1 polymorphism in MDS risk, probably in an age-dependent manner.

CYP2B6 is a polymorphic detoxification gene which plays a vital role in the degradation of genotoxic compounds. In this study we hypothesized that inadequate detoxification due to CYP2B6 polymorphisms may contribute to AML. To evaluate the potential impact of CYP2B6 polymorphisms on AML development and induction of its specific chromosomal abnormalities we studied C 777 A and A 785 G polymorphisms for the first time in AML. Furthermore, we investigated the co-existence of the above polymorphisms with G 516 T polymorphism to determine the CYP2B6 high-risk haplotypes in AML susceptibility. Our study included 619 AML patients and 430 healthy donors. Concerning C 777 A CYP2B6 polymorphism, no significant difference was found between patients and controls. However, A 785 G CYP2B6 polymorphism showed a statistically higher frequency of the variant genotypes in patients (48.2%), mainly in secondary AML patients (49.1%) than in controls (26.1%). Moreover, an increased frequency of the variant genotypes was found in those with abnormal karyotypes, especially with −7/del(7q), −5/del(5q), +8, inv(16) and t(8;21). The combination of the three CYP2B6 polymorphisms (G 516 T, C 777 A & A 785 G) revealed seven haplotypes. Four out of six haplotypes with at least one mutant allele were significantly associated with an increased risk for AML. Interestingly, T 516 A 777 G 785 haplotype, where the three mutant alleles co-existed, had ~3-fold increased risk to be found in patients than controls. The association between haplotypes and cytogenetic aberrations revealed a positive correlation between specific CYP2B6 haplotypes and AML cytogenetic abnormalities. Our data suggest that A 785 G CYP2B6 gene polymorphism and specific CYP2B6 haplotypes may contribute to AML and its specific chromosomal aberrations.

Genomic aberrations are important indicators of prognosis, clinical course and treatment of chronic lymphocytic leukemia (CLL). Two cytogenetic methods, karyotype, and FISH, with still ongoing improvements, are used for CLL investigation, but the panel of chromosomal abnormalities, their prognostic significance and contribution in CLL pathogenesis have not been elucidated yet.Our study deals with the cytogenetic investigation of 237 CLL patients trying to answer ambiguous issues of the disease in the light of new CLL stimulation methodology. More specifically, we compared the detection rate and type of chromosomal aberrations between cultures stimulated with and without the new mitogens and we combined them with the data obtained from interphase (iFISH) and metaphase FISH (mFISH).Approximately 70% of the abnormal karyotypes and all the subclonal abnormalities were detected exclusively in DSP-30/IL-2 cultures. DSP-30/IL-2 exhibited ∼10-fold greater ability to detect abnormalities compared to TPA and unstimulated cultures, revealing60 different chromosomal aberrations. Moreover, the comparison between DSP-30/IL-2 cultures and unstimulated cultures indicated that loss of chromosome Y is rather an age-related phenomenon and not a specific aberration of CLL. Clonal evolution was also detected in 50% of patients with available follow-up karyotypic data and changed the prognosis in 86.4% of them. Finally, it was shown that mFISH must be performed in DSP-30/IL-2 cultures in addition to iFISH to uncover submicroscopic translocations or insertions undetectable by iFISH.All the above argue in favor of the parallel application of karyotype, iFISH and mFISH after DSP-30/IL-2 stimulation for CLL clinical practice and research.

Acute myeloid leukemia (AML) is defined as a clonal proliferation of immature hematopoietic progenitors with varying degree of myeloid differentiation in the bone marrow, peripheral blood or extram...

Chronic lymphocytic leukemia (CLL) is associated with recurrent cytogenetic abnormalities that are important prognostic indicators and may influence treatment choices. Nonetheless, several chromosome abnormalities have not yet been completely determined, because of the low mitotic in vitro activity of B-CLL cells. Now, novel technologies such as stimulation of CLL cells with new B-cell mitogens have helped to overcome this problem. We present here a novel conventional and molecular cytogenetic study of a CLL patient with t(6;13)(p21;q14.1), a rare chromosomal aberration. The findings contribute to the identification of rare recurrent aberrations and of any prognostic effect in CLL that could be used for prognostic and therapeutic purposes. The present study demonstrates that t(6;13)(p21;q14.1) as a secondary event to the interstitial deletion in 13q14 region, resulting in the loss of RB1, is a rare but nonrandom abnormality in CLL, resistant to the current treatment CLL protocols with a rather favorable or intermediate prognosis but definitely not an adverse prognosis. Further studies in more CLL patients are required to delineate the prognostic value of t(6;13)(p21;q14.1) and to identify any candidate genes with potential role in the pathogenesis of the disease.

Acute myeloid leukemia (AML) is a clinically and genetically heterogeneous disease accounting for 15-20% of all childhood acute leukemias, while it is responsible for more than half of the leukemic deaths in these patients. This article focuses on the significance of cytogenetic analysis in pediatric AML supporting the importance of cytogenetic analysis in the pathogenesis, diagnosis, prognosis, follow-up and treatment selection in childhood AML. It reviews in detail the types and frequencies of most common chromosomal aberrations, their molecular background, their correlation with French American British (FAB) subtypes and age distribution and their prognostic relevance. It also summarizes some less frequent or rare chromosome aberrations in which the prognostic classification has not been determined yet owning to the small number of patients and the variable treatment modalities used in different study groups. Furthermore, it discusses the association of specific chromosome rearrangements with prenatal exposure to carcinogenic agents or therapeutic agents and highlights the ongoing and future research on pediatric AML in the evolving field of Cytogenetics.

Jumping translocations (JT) are rare cytogenetic aberrations in hematological malignancies that include unbalanced translocations involving a donor chromosome arm or chromosome segment that has fused to two or more different recipient chromosomes in different cell lines. We report five cases associated with different hematologic disorders and JT to contribute to the investigation of the origin, pathogenesis, and clinical significance of JT. These cases involve JT of 1q in a case of acute myeloblastic leukemia (AML)-M1, a case of Burkitt lymphoma, and a case of BCR/ABL-positive acute lymphoblastic leukemia, as well as a JT of 13q in a case of AML-M5, and a JT of 11q segment in a case of undifferentiated leukemia. To our knowledge, with regard to hematologic malignancies, this study presents the first case of JT associated with AML-M1, the first case of JT involving 13q as a donor chromosome, and the first report of JT involving a segment of 11q containing two copies of the MLL gene, jumping on to two recipient chromosomes in each cell line and resulting in six copies of the MLL gene. Our investigation suggests that JT may not contribute to the pathogenesis but rather to the progression of the disease, and it demonstrates that chromosome band 1q10 as a breakpoint of the donor chromosome 1q is also implicated in AML, not only in multiple myeloma as it has been known until now.

We describe a case of treatment-induced acute myeloid leukemia M2 after breast cancer with a rare reciprocal t(12;12)(p13;q13) as a secondary cytogenetic abnormality in addition to the t(11;19)(q23;p13.1). Fluorescence in situ hybridization analysis revealed that both ETV6 genes (previously TEL) were located on the same der(12)t(12;12) as a result of t(12;12). Interestingly, the translocated ETV6 gene was disrupted, indicating the breakpoint on the large der(12)t(12;12) to be within the ETV6 gene and thus the possible formation of a new fusion gene. CHOP gene at 12q13, was found to be translocated intact to the other homologue chromosome 12, indicating that the breakpoint on the small der(12) is proximal to CHOP. To the best of our knowledge, our patient represents the first report of the rare t(12;12)(p13;q13) described in treatment-induced leukemia and the possible formation of a new fusion gene.

A reciprocal t(X;12)(p11;p13) was found as the sole clonal abnormality in biphenotypic leukemia with myeloid and B-lymphoid differentiation. With fluorescence in situ hybridization analysis, the ETV6 gene (previously TEL) was found to be translocated intact to the derivative X chromosome; no MLL and BCR/ABL rearrangements were found. The patient achieved complete remission after induction chemotherapy. To our knowledge, this cytogenetic aberration has not been reported previously as a sole abnormality in hematological malignancies. Its presence may suggest an important role in the pathogenesis of biphenotypic leukemia.

Recent reports suggest that hemopoietic stem cells with constitutional pericentric inversion of chromosome 9 [inv(9)] may be related to delayed engraftment or hemopoietic defect after stem cell transplantation (SCT). We conducted a retrospective study on five allogeneic SCT in which constitutional inv(9) was detected either in the donor or the recipient. The results showed that hematologic recovery was within the expected time range for all our patients. However, one patient exhibited decreasing blood counts between day +45 and +272 after transplantation, possibly due to protracted cytomegalovirus (CMV) infection and gansiclovir and imatinib treatment. Our findings suggest that constitutional inv(9) may not be associated with delayed hemopoietic recovery after SCT.

The unbalanced t(1;9) is a rare, recurrent rearrangement in polycythemia vera (PV) resulting in trisomy of both 1q and 9p arms, whereas a balanced t(1;9)(q12;q12), to our knowledge, has never been reported before. We studied two patients with PV and one with idiopathic myelofibrosis bearing an unbalanced t(1;9) and one patient with essential thrombocythemia with a balanced t(1;9). In all cases fluorescence in situ hybridization showed that the breakpoints were located within the satellite II family of heterochromatin of chromosome 1 and the satellite III of chromosome 9. Heterochromatin breakage and reunion produce the unbalanced t(1;9) and may contribute to a gene dosage effect due to gains of 1q and 9p. Case 4 with the balanced t(1;9), however, suggests that translocation of heterochromatin close to critical genes could interfere with their function. The molecular event underlying juxtaposition of satellite II of chromosome 1 and the satellite III of chromosome 9 remains to be elucidated.

Chronic lymphocytic leukemia (CLL) has been recently attributed to a combination of genetic predisposition and exposure to environmental factors. UDP-glucuronosyltransferase (UGT)1A1*28 is an inborn polymorphism that results in significant downregulation of uridine diphosphate glucuronyltransferase 1-1 (UGT1A1) activity, one of the most critical metabolizing enzymes involved in the detoxification of toxic substances, some of which contribute to CLL pathogenesis. Here, for the first time, we investigated the putative impact of UGT1A1*28 on CLL incidence and on the formation of the most common chromosomal abnormalities of CLL. UGT1A1*28 was investigated in 109 CLL patients and 108 healthy controls, and was associated with karyotypic and fluorescence in situ hybridization (FISH) results. A significant high frequency of the mutant genotype was observed in patients carrying abnormal FISH patterns, especially del(11q) and +12, which are CLL-specific abnormalities. We also observed a significant association between UGT1A1*28 and the intermediate to unfavorable cytogenetic CLL risk groups. No difference, though, was observed in genotypes between patients and controls. Therefore, we could suggest that UGT-deficient individuals may be at a greater risk for developing CLL-specific abnormalities. Our study might serve as a starting point to consider UGT1A1*28 polymorphism as one of the possible predisposing factors of CLL pathogenesis.

The whole spectrum of chromosomal abnormalities and their prognostic significance in children and adolescents with acute myeloid leukemia (AML) has not been fully elucidated yet, although a considerable amount of knowledge has been gained recently. Moreover, the incidence and prognostic impact of monosomal karyotypes (MKs), which are new cytogenetic categories reported recently in adults with AML, are currently unknown for childhood and adolescent AML. In this study, we investigated the cytogenetic and clinical characteristics of 140 children and adolescents (≤21 y) with AML, and correlated their cytogenetic features with both the clinical characteristics and outcomes of our patient cohort. The most frequent cytogenetic abnormality found in our study was the t(15;17), followed by the t(8;21). Striking differences in the genetic abnormalities and French-American-British subtypes were found among infants, children, and adolescents. Of 124 cases, 15 (12.1%) met the criteria of the MK definition, and 12 of the 15 MKs (80%) were complex karyotypes. Of 124 cases, 27 (21.8%) had cytogenetic abnormalities sufficient to be diagnosed as AML with myelodyspastic sydrome–related features. As expected, patients with the t(15;17) had the most favorable outcomes, whereas patients with 11q23 rearrangements and monosomy 7 had the worst outcomes. These data expand our knowledge by providing novel insights into the cytogenetic features and their correlations with clinical characteristics and outcomes in childhood and adolescent AML.

We report on a case of refractory anemia with trilineage dysplasia and an unbalanced der(1)t(1;10) that resulted in trisomy of the long arm of chromosome 1 (1q) and monosomy of the short arm of chromosome 10 (10p). Fluorescence in situ hybridization showed that the rearranged chromosome contained the centromeres of both chromosomes 1 and 10, leading to a dic(1;10). To our knowledge, a dicentric chromosome involving chromosomes 1 and 10 has never been described in hematological malignan- cies.

Deletions of the long arm of chromosome 5 [del(5q)] are frequent chromosome aberrations with known prognosis in myelodysplastic syndromes and acute myeloid leukemia (AML). However, in chronic lymphocytic leukemia (CLL), they are rare and have been reported only as karyotypic results without known prognosis. In the present study, we report a novel conventional and molecular cytogenetic study of two CLL patients carrying interstitial del(5q) in order to contribute to the identification of rare recurrent aberrations and their prognostic impact in CLL. Karyotypic and fluorescence in situ hybridization analysis that used probes for the most common aberrations of CLL demonstrated that del(5q) was the sole chromosome abnormality in both patients at the time of diagnosis. None of these patients had a history of exposure to chemotherapy or radiotherapy. Both patients had disease that was still staged as Binet A at 28 and 18 months after diagnosis, respectively, without receiving any therapy because of their good clinical condition. Therefore, it could be suggested that del(5q) may not be associated with an adverse prognosis in CLL and is not related with therapy-induced chromosome changes. Further studies are required to elucidate the prognostic value of these deletions in more CLL patients, which could be advisable for prognostic and therapeutic purposes, as well as to identify candidate genes that may potentially play a role in the pathogenesis of CLL.

Isochromosome of the long arm of the derivative chromosome 17, originating from the translocation t(15;17) [ider(17)(q10)t(15;17) or ider(17q)] in acute promyelocytic leukemia (APL), is a rare chromosome aberration which has been associated with a poor prognosis. In the present study, we report on 4 male APL patients with ider(17q) and review the clinical, cytogenetic and molecular characteristics of all previously reported APL patients with ider(17q) in order to clarify the clinical features and outcome of these patients. The data presented in this study demonstrated that ider(17q), which resulted in an extra RARA-PML fusion gene, was more frequent in males than females (male/female ratio of 2.12/1), was associated with a rather low initial white blood cell count and did not confer an adverse prognosis in APL patients treated with all-trans-retinoic acid and chemotherapy. The most frequent additional chromosome change to ider(17q) was trisomy 8. Ider(17q) was observed in all subtypes of the PML-RARA fusion gene, but the frequency of the bcr1 subtype was increased. Cases of overrepresentation of the RARA-PML fusion gene and ider(17q) cases may help in elucidating the role of RARA-PML in leukemogenesis.

Increased yield of chromatid breaks, following in vitro G2-phase lymphocyte irradiation, can be a marker of individual radiosensitivity and cancer predisposing genes whose role is to respond to DNA damage. Mutations or polymorphisms of genes encoding DNA repair pathways may underlie the increased chromosomal radiosensitivity. However, genes that facilitate DNA damage recognition, using signal transduction pathways to activate cell cycle arrest and preserve genomic integrity, are perhaps the most important determinant. Based on the latter hypothesis, an individual radiosensitivity parameter (IRP) is introduced, which expresses, at individual level, the G2-checkpoint potential to facilitate DNA damage recognition and repair of radiation-induced chromosomal damage during G2 to M-phase transition. Based on this parameter a new methodology for assessment of individual radiosensitivity is proposed, which involves G2-checkpoint abrogation by caffeine to obtain the IRP values. To evaluate the proposed methodology, blood samples from 52 healthy donors were taken for inter-individual radiosensitivity analysis using both the conventional G2 chromosomal radiosensitivity assay as well as the new approach using caffeine-induced G2-checkpoint abrogation. The two assays were compared in experiments using samples from 5 hypersensitive patients, 3 AT-homozygotes, 3 AT-heterozygotes, and the GM15786, GM03188A, GM09899, HCC1937 and MCF-7 cell lines. Using the G2 chromosomal radiosensitivity assay, donors are predicted as G2 radiosensitive or normal, while according to the new approach, individuals can be classified as highly radiosensitive, radiosensitive, normal, radioresistant and highly radioresistant. Overall, the new approach provides better individual radiosensitivity discrimination and intra-experimental reproducibility. Therefore, the proposed methodology using IRP values may provide a clinically applicable predictive assay for individual radiosensitivity and predisposition to cancer.

Submicroscopic deletions of the PML-RARA fusion genes constitute rare rearrangements in acute promyelocytic leukemia (APL). We describe a rare case of APL carrying a novel complex translocation involving chromosomes 15, 17, and 18 associated with a submicroscopic deletion of the 5' part of the RARA gene, as evidenced by fluorescence in situ hybridization (FISH). A PML/RARA dual-fusion probe did not reveal the RARA-PML fusion signal on the der(17q), usually detected in the typical t(15;17). The RARA break-apart probe showed a deletion hybridization pattern with loss of the signal corresponding to the 5' portion of the RARA gene. Reverse transcriptase-polymerase chain reaction confirmed the absence of the fusion RARA-PML transcript. The patient achieved complete remission, but died during consolidation therapy, 2 months after diagnosis. To our knowledge, this is the first reported case of APL with a complex variant t(15;17) involving chromosome 18 at band q12 and one of the very rare described cases displaying a submicroscopic deletion of the RARA 5' region. Further cases are needed to delineate the incidence of submicroscopic deletions in APL and elucidate their prognostic impact.

Oxidative stress has been implicated in the pathogenesis of multiple sclerosis (MS). Glutathione-S-transferases (GSTs) are detoxification enzymes, evolved to protect cells against reactive oxygen metabolites. Both GSTT1 and GSTM1 genes exhibit a homozygous deletion polymorphism (null genotype) leading to abolished enzyme activity. We studied the impact of the GSTT1 and GSTM1 polymorphisms on MS susceptibility in a case–control study of 47 Greek patients and 165 controls. Correlations between genotype, gender and disability status were also investigated. The incidence of both GSTT1 and GSTM1 genotypes did not differ significantly between controls and patients. A significantly increased frequency of GSTM1 null genotype was found amongst female patients (65.5%) as compared with males (33.3%, P ¼ 0.04). The results suggest that GSTT1 and GSTM1 have no major pathogenetic role on the MS occurrence, nor any strong modifying effect on the disability status. The higher incidence of GSTM1 null genotype observed in female patients, suggests a possible role of the GSTM1 detoxification pathway in a gender-dependent manner.

Cases of leukemia associated with Turner syndrome (TS) are rare. Here we report three TS patients with leukemia including one case of T-large granular lymphocyte leukemia (T-LGL), one rare case of coexistence of chronic lymphocytic leukemia (CLL) and idiopathic myelofibrosis (IMF) and one case of a patient with AML-M2 who received autologous stem cell transplantation (SCT). T-LGL and coexistence of CLL and IMF associated with TS are reported for the first time while the last case represents the first report of SCT in a leukemia patient with TS. Our cases and the limited data of previously reported leukemia patients with TS suggest that TS is not associated with a specific type of leukemia and that presentation, clinical course and response to treatment are similar to that of the non-TS leukemia patients. However, these patients may have a higher risk of liver complications. Interestingly, in the mosaic TS patients, the abnormal clones were restricted to the monosomic 45,X cells, indicating that the leukemic clones possibly originate from the monosomic cell line. Even in cases with no additional chromosome abnormalities, the ratio of X/XX cells in bone marrow cells was significantly increased compared to that in constitutional karyotype, indicating that monosomic cells possibly provide a survival advantage for leukemia cells or that reduced programmed cell death may be responsible for the expansion of the monosomic cells.

We report a JAK2 V617F-negative case of polycythemia vera with two acquired balanced X-autosome translocations and no history of previous exposure to chemo/radiotherapy. The patient's first clone carried a novel translocation t(X;15)(q24;q13) as a sole abnormality. The second clone exhibited an additional translocation, t(X;20)(q13;q13.3), which is a rare recurrent abnormality in myeloid malignancies. This is the first report of a hematological disorder with both X chromosomes being translocated. Late replication studies revealed a switch in X-inactivation from the X chromosome involved in t(X;15) (first clone) to the X chromosome involved in the t(X;20)(q13;q13.3) (second clone). The inactivation of the translocated X chromosomes could provide potential for the inactivation of the adjacent autosomal regions, resulting in epigenetic gene silencing.

The etiology of acute myeloid leukemia (AML) underlies the influence of genetic variants in candidate genes. The CYP2B6 enzyme detoxifies many genotoxic xenobiotics, protecting cells from oxidative damage. The CYP2B6 gene is subjected to a single-nucleotide polymorphism (G516T) with heterozygotes (GT) and homozygotes (TT) presenting decreased enzymatic activity. This case-control study aimed to investigate the association of CYP2B6 G516T polymorphism with the susceptibility of AML and its cytogenetic and clinical characteristics. Genotyping was performed on 619 AML patients and 430 healthy individuals using RCR-RFLP and a novel LightSNip assay. The major finding was a statistically higher frequency of the variant genotypes (GT and TT) in patients compared to the controls (GT:38.8% vs 29.8% and TT:9.3% vs 5.3% respectively) (p

Abstract 2513 Acute myeloid leukemia (AML) is a heterogeneous disease with well-known clinical and pathological aspects, characterized by the acquisition of somatic mutations in haematopoietic progenitors leading to disruption of differentiation. However, the genetic etiology of AML, which include gene mutations and chromosomal aberrations, is largely unknown. Altered forms of genes that differ by a single nucleotide polymorphisms (SNPs) have been shown to predispose individuals to AML development. Recently it has been reported that interindividual differences based on detoxification genes polymorphisms may contribute to the AML susceptibility. Human cytochrome P450 (CYP) enzymes play a key role as phase I enzymes in the metabolism of drugs and environmental chemicals. Several CYP enzymes metabolically activate procarcinogens to genotoxic intermediates. CYP2B6 blocks the transformation of precarcinogens to their biologically active forms that provoke chromosomal instability and leukemia. CYP2B6 G516T SNP change the aminoacid sequence (Gln172His), resulting in enzymatic inactivation. Thus, individuals homozygous for the mutant allele (T/T) or heterozygotes (G/T) present decreased enzymatic activity. We performed a case-control study in a large series of AML patients to investigate the potential relation between genotype of CYP2B6 G516T SNP and the risk of de novo AML. We also compared the genotypic frequencies in AML patients in respect to chromosome abnormalities, FAB classification and clinical characteristics. The CYP2B6 G516T genotyping was performed on 195 de novo AML patients at diagnosis and 215 sex and age matched healthy controls using a PCR-RFLP assay and LightSNP assay. Unstimulated bone marrow cells were used for karyotypic analysis and karyotypes were described according to ISCN. Statistical analysis was performed using Chi-square test and P Karyotypic analysis was successfully performed in 97.8% of AML patients at diagnosis. Among them, 136 (69.7%) showed clonal karyotypic abnormalities. The genotypic distribution in patients and healthy groups was statistically significant and showed: homozygous wild type G/G 54,5% vs 67.2%, heterozygotes G/T 40.4% vs 27.5% and homozygous mutant T/T 6.7% vs 5.5% respectively (p The increased frequency of mutant allele leading to reduced enzyme activity suggests that the CYP2B6 gene may be a predisposing factor for the development of AML. Furthermore, the CYP2B6 G516T polymorphism seems to be associated with the presence of lesions on chromosomes 5 and / or 7 which are poor prognostic lesions in AML. Therefore, the high frequency of mutant genotypes (G/T and T/T) of CYP2B6 G516T SNP in these cytogenetic groups may be involved in the development of these specific chromosomal abnormalities. Disclosures: No relevant conflicts of interest to declare.

Acute myeloid leukemia (AML) accounting for approximately 17% of all childhood acute leukemias, arises either de novo or from a backround of myelodysplasia or previous chemotherapy. Cytogenetics is considered one of the most valuable prognostic determinants in AML while current risk–group classification in the limited cases of pediatric AML, is mainly based on cytogenetics and early treatment response. We reviewed the clinical and cytogenetic characteristics and the outcomes of 33 cases of childhood AML between 1997 and 2007 in order to investigate the incidence of the main FAB subtypes, the incidence of primary AML compared to secondary AML (s-AML) and the correlation between specific chromosome abnormalities and outcome in greek pediatric AML patients. Chromosome studies were performed on unstimulated bone marrow cells, derived from 33 pediatric AML patients, who were