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Introduction: The activated partial thromboplastin time (aPTT) and the prothrombin time (PT) are widely available coagulation parameters which are however poor predictors of the anticoagulant effect of direct oral anticoagulants (DOACs). Some coagulometers use the clot waveform analysis (CWA) to assess the clotting time but mainly based on a unique parameter. The improvement of these methodologies and the evaluation of the other waveform parameters may increase the sensitivity to DOACs., Objectives: To assess the performance of an improved clot waveform an method (i.e. FibWave) to detect the impact of edoxaban on the coagulation and the fibrinolytic systems., Methods: Seventy-one samples from patients treated with edoxaban collected at minimum concentration (C TROUGH ) and/or maximum concentration (C MAX ), and 45 control samples were included. The aPTT- and PT-based CWA as well as the FibIn, FibEx, and FibLysis methodologies of the FibWave were implemented and performed on an ACL-TOP 700., Results: PT and FibEx clotting time were strongly correlated to edoxaban concentration (Pearson r  = 0.80 and 0.89, respectively). The FibEx clotting time allowed a better discrimination for samples with 30 and 50 ng/ml of edoxaban compared to PT (cutoffs of 96.5 and 114.2 s for the FibEx versus a unique cutoff of 13.1 s for the PT). The fibrinolytic process was impaired in the presence of edoxaban in a dose-dependent manner., Conclusion: FibEx is more sensitive than aPTT- and PT-based CWA for the detection of the clinically relevant anticoagulant level of edoxaban., (© 2022 The Authors. Research and Practice in Thrombosis and Haemostasis published by Wiley Periodicals LLC on behalf of International Society on Thrombosis and Haemostasis (ISTH).)

Introduction: Edoxaban is the only anti-Xa inhibitor metabolized in pharmacologically active moiety that could interfere with chromogenic anti-Xa assays, especially in case of drug-drug interactions or physiological disorders., Materials and Methods: We evaluated the contribution of the main metabolite of edoxaban, edoxaban-M4 (M4), in 79 plasma samples from patients taking edoxaban. The total anti-Xa activity was evaluated on three different chromogenic factor Xa-based assays. Results were compared with a validated ultra-high-performance liquid chromatography coupled with a tandem mass spectrometry measurement. Edoxaban and its active M4 metabolite have also been spiked separately in normal pooled plasma to assess the sensitivity of chromogenic anti-Xa assays to both molecules individually., Results: Spiked edoxaban or M4 provided different slopes of linear regression models between chromogenic and chromatographic measurement (from 0.97 for STA Liquid Anti-Xa to 1.10 for Biophen Heparin LRT Low with edoxaban and from 0.70 for Biophen DiXaI High to 0.83 for Biophen Heparin LRT High, respectively). A positive correlation is observed between the increase of the ratio M4/edoxaban with the difference between chromogenic and chromatographic measurements., Conclusion: Edoxaban and M4 do not similarly impact chromogenic assays, leading to biased chromogenic estimations of ponderal concentrations. In patient samples, this impact is even more important at low concentrations or in the case of an increase in the M4/edoxaban ratio because of hepatic or renal impairments or in case of drug interactions. This study highlights the limitations and risks of error of expressing results in ponderal concentrations instead of global activity anti-Xa., (© 2022 The Authors. Research and Practice in Thrombosis and Haemostasis published by Wiley Periodicals LLC on behalf of International Society on Thrombosis and Haemostasis (ISTH).)

In oncology, the identification of targets that correlate with a type of cancer has led to a profound change in the notion of "tumor markers". Technological advances, in particular the development of high-throughput sequencing, have led to the emergence of a new generation of molecular biomarkers for tumors. Despite their limited utility for screening and diagnosis, conventional tumor markers remain interesting for evaluation of prognoses, the choice and optimization of treatments, as well as for monitoring the effectiveness of those treatments. In this article, we revisit the conventional serum markers that are enjoying a 'come back' thanks to the development of high-performance scores based on biological, cytological, clinical, or radiological criteria., (Copyright © 2021 Société Française du Cancer. Published by Elsevier Masson SAS. All rights reserved.)

Technological advances, in particular the development of high-throughput sequencing, have led to the emergence of a new generation of molecular biomarkers for tumors. These new tools have profoundly changed therapeutic management in oncology, with increasingly precise molecular characterization of tumors leading to increasingly personalized therapeutic targeting. Detection of circulating tumor cells and/or circulating tumor DNA in blood samples -so-called 'liquid biopsies'- can now provide a genetic snapshot of the patient's tumor through an alternative and less invasive procedure than biopsy of the tumor tissue itself. This procedure for characterizing and monitoring the disease in real time facilitates the search for possible relapses, the emergence of resistance, or emergence of a new therapeutic target. In the long term, it might also provide a means of early detection of cancer. These new approaches require the treatment of ever-increasing amounts of clinical data, notably, with the goal of calculating composite clinical-biological predictive scores. The use of artificial intelligence will be unavoidable in this domain, but it raises ethical questions and implications for the health-care system that will have to be addressed., (Copyright © 2021 Société Française du Cancer. Published by Elsevier Masson SAS. All rights reserved.)

Background: The expression of programmed death (PD) ligand 1 (PD-L1) protein expression assessed by immunohistochemistry (IHC) has been correlated with response and survival benefit from anti-PD-1/PD-L1 immune checkpoint inhibitor therapies in advanced non-small cell lung carcinoma (NSCLC). The efficacy of several agents appears correlated with PD-L1 expression. It remains controversial whether PD-L1 is prognostic in NSCLC. We assessed the prognostic value of PD-L1 IHC and its predictive role for adjuvant chemotherapy in early stage NSCLC., Patients and Methods: Tumor sections from three pivotal adjuvant chemotherapy trials (IALT, JBR.10, CALGB 9633) using the E1L3N antibody were studied in this pooled analysis. PD-L1 staining intensity and percentage in both tumor cells (TCs) and immune cells (ICs) were scored by two pathologists. The average or consensus PD-L1 expression levels across intensities and/or percent cells stained were correlated with clinicopathological and molecular features, patient survivals and potential benefit of adjuvant chemotherapy., Results: Results from 982 patients were available for analysis. Considering staining at any intensities for overall PD-L1 expression, 314 (32.0%), 204 (20.8%) and 141 (14.3%) tumor samples were positive for PD-L1 staining on TCs using cut-offs at ≥1%, ≥10% and ≥25%, respectively. For PD-L1 expressing ICs, 380 (38.7%), 308 (31.4%) and 148 (15.1%) were positive at ≥ 1%, ≥10% and 25% cut-offs, respectively. Positive PD-L1 was correlated with squamous histology, intense lymphocytic infiltrate, and KRAS but not with TP53 mutation. EGFR mutated tumors showed statistically non-significant lower PD-L1 expression. PD-L1 expression was neither prognostic with these cut-offs nor other exploratory cut-offs, nor were predictive for survival benefit from adjuvant chemotherapy., Conclusions: PD-L1 IHC is not a prognostic factor in early stage NSCLC patients. It is also not predictive for adjuvant chemotherapy benefit in these patients., (© The Author 2017. Published by Oxford University Press on behalf of the European Society for Medical Oncology. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Introduction: Tumor protein p53 gene (TP53) mutations are common in stage I through III non-small cell lung cancer, but clinical trials have shown inconsistent results regarding their relationship to the effects of adjuvant therapy. The objective is to clarify their putative prognostic and predictive effects., Methods: A pooled analysis of TP53 mutations (exons 5-8) was conducted in four randomized trials (the International Adjuvant Lung Cancer Trial, J BRonchus 10, Cancer and Leukemia Group B-9633, and Adjuvant Navelbine International Trialist Association trial) of platinum-based adjuvant chemotherapy (ACT) versus observation (OBS). Hazard ratios (HRs) and 95% confidence intervals (CIs) of mutant versus wild-type (WT) TP53 for overall survival (OS) and disease-free survival (DFS) were estimated using a multivariable Cox model stratified on trial and adjusted on sex, age, and clinicopathological variables. Predictive value was evaluated with an interaction between treatment and TP53., Results: A total of 1209 patients (median follow-up 5.5 years) were included. There were 573 deaths (47%) and 653 DFS events (54%). Mutations (434 [36%]) had no prognostic effect (OBS HROS = 0.99, 95% CI: 0.77-1.28, p = 0.95; HRDFS = 0.99, 95% CI: 0.78-1.25, p = 0.92) but were marginally predictive of benefit from ACT for OS (test for interaction: OS, p = 0.06; DFS, p = 0.11). Patients with WT TP53 had a tendency toward better outcomes with ACT than did those in the OBS group (HROS = 0.77, 95% CI: 0.62-0.95, p = 0.02; HRDFS = 0.75, 95% CI: 0.62-0.92, p = 0.005). In the ACT arm, a deleterious effect of mutant versus WT TP53 was observed (HROS = 1.40, 95% CI: 1.10-1.78, p = 0.006; HRDFS = 1.31, 95% CI: 1.04-1.64, p = 0.02)., Conclusions: TP53 mutation had no prognostic effect but was marginally predictive for survival from ACT. In patients who received ACT, TP53 mutation tended to be associated with shorter survival than wild-type TP53., (Copyright © 2016 International Association for the Study of Lung Cancer. Published by Elsevier Inc. All rights reserved.)

Germline mutations in TP53 are the underlying defects in Li-Fraumeni syndrome (LFS) and its variant, Li-Fraumeni-like (LFL) Syndrome, autosomal dominant disorders that are characterized by predisposition to multiple early onset cancers. Here, we identified rs78378222 (A > C), a rare variant that is located in the 3' untranslated region (3' UTR) of TP53, in 7 probands (5.4%) of a cohort from LFS/LFL patients without TP53 germline mutations in the coding regions. To support its association with the LFS/LFL phenotype, we assessed p53 expression in tumor specimens and fibroblasts from rs78378222[C] carriers. Additionally, we investigated using in silico tools the evolutionary conservation and whether rs78378222[C] affects microRNA (miRNA) binding sites in the 3' UTR of TP53 mRNA. We found lower p53 protein levels in biological samples from rs78378222[C] carriers. Additionally, we showed that rs78378222[C] could interfere with a putative target site of miR-545-3p, a novel miRNA that is predicted to directly target the 3' UTR TP53. To our knowledge, this is the first description of rs78378222[C] in LFS/LFL patients. Moreover, these findings suggest that rs78378222[C] lead to haploinsufficiency of p53, a new mechanism of carcinogenesis in LFS/LFL., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Purpose: Assessment of breast cancer (BC) pattern in individual states with respect to ethnicity., Methods: Population-based cancer registries from the Cancer Incidence in Five Continents databases (1998-2007) supplemented with Surveillance, Epidemiology, and End Results data from 2008 to 2010 were used., Results: The age-specific burden showed a clear convergence of BC burden among African American (AA) and Caucasian American (CA) in most states. This was primarily because of a decrease in the BC rate among CA aged 50 years or older and an increase among AA of the same age group. The 2003-2007/1998-2002 rate ratio for CA was 0.91 (95% confidence interval [CI], 0.90-0.91) in the South, whereas it was 1.06 (95% CI, 1.04-1.08) for AA. This convergence was confirmed in states with available data for the period 2008 to 2010. The AA/CA rate ratio among women aged younger than 40 years was 0.99 (95% CI, 0.99-1.04) in the Northeast, 1.29 (95% CI, 1.25-1.33) in the South, and 1.10 (95% CI, 1.04-1.17) in the West. This pattern correlates with the estrogen receptor positive and progesterone receptor positive pattern. The strongest disparity in estrogen receptor negative was observed in Louisiana which with Detroit, have had the highest rates of estrogen receptor negative., Conclusions: The changes in postmenopausal hormone use and mammography screening might have played a role in the observed convergence., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Background: In lung adenocarcinoma, inactivation of the tumor suppressor p53 may abrogate a safeguard mechanism preventing the development of tumors with activating mutations in EGFR or KRAS. To assess this hypothesis, we analyzed TP53 mutations and downregulation of p14(arf), a negative regulator of p53 activated by oncogenic signals, in a retrospective series of 96 patients with primary adenocarcinoma of the lung., Patients and Methods: Mutations in TP53 (exons 4-9), KRAS (exon 1), and EGFR (exons 18-21) were identified by direct sequencing of DNA from formalin-fixed, paraffin-embedded resected tumors. Expression of p14(arf) was semiquantitatively evaluated by immunohistochemical analysis., Results: TP53, KRAS, and EGFR mutations were detected in 42 of 93 (45.2%), 15 of 95 (15.8%), and 31 of 90 (34.4%) cases, respectively. Low p14(arf) expression was observed in 19 of 91 cases (20.9%). Disruption of the p53/p14(arf) pathway (defined as TP53 mutation or decreased p14(arf) expression, or both) was observed in 18 of 31 EGFR-mutated (58.1%) tumors and in 9 of 13 KRAS-mutated (69.2%) tumors., Conclusion: Inactivation of the p53/p14(arf) pathway is common but not systematic in EGFR- or KRAS-mutated lung adenocarcinomas. Our work highlights the need to better investigate the association between EGFR and KRAS mutations and alterations in tumor suppressor pathways., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Background: In West Africa, trends and risk factors for breast cancer (BC) have been rarely studied., Methods: Here we have analyzed trends of BC over two periods in two population-based cancer registries, in Mali-Bamako (1987-1997; 1998-2009) and in The Gambia (1988-1997; 1998-2006). We have conducted a case-control study (n = 253 cases, 249 controls) on risk factors associated with reproductive life stratified by menopausal status in Bamako., Results: Between the two periods, BC incidence rates increased by 20% (incidence rate ratio (IRR) 1.20 (95% CI [1.07-1.35])) in Bamako, with an annual percentage change of 2% (95% CI [0.4-3.6]). The increase was of 30% in women under 55 years (IRR 1.30 (95% CI [1.14-1.60])). A similar pattern was observed in The Gambia for women under 50 years (IRR 1.47 (95% CI [1.07-2.01])). Overall, pre-menopausal breast cancer was predominant in both countries. In contrary to what is well established, case-control study showed that late age at menarche (>14 years) increased the risk of BC among pre-menopausal women (OR: 2.02 (95% CI [1.08-3.78])) while it tended to be protective in post-menopausal women (OR: 0.61 (95% CI [0.29-1.29])). Later age at a first pregnancy (>20 years) was associated with a reduction of risk in pre-menopausal women (OR: 0.41 (95% CI [0.18-0.89]))., Conclusion: These results indicate that the burden of pre-menopausal BC is increasing in West African countries. These cancers appear to be associated with distinct reproductive risk factors, highlighting the need for better understanding the biological bases of early BC in African populations., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Introduction: The Evaluation of the epidermal growth factor receptor (EGFR) Mutation status for the administration of EGFR-Tyrosine Kinase Inhibitors in non-small cell lung Carcinoma (NSCLC) (ERMETIC) project part 1 assessed the accuracy of EGFR and KRAS mutations detection in NSCLC among 15 French centers., Methods: The 15 ERMETIC centers selected 74 NSCLC surgical specimens from previously untreated patients. Paraffin and paired frozen DNA were sequenced for EGFR exons 18 to 21 and KRAS exon 2 by an external molecular laboratory, yielding a gold standard. The 74 blinded paraffin DNAs were redistributed to the 15 ERMETIC laboratories for sequencing of a total of 5550 exons. Results were compared with the gold standard and between centers by discordance rates and kappa statistics., Results: The gold standard included 39 mutated samples with 22 EGFR and 17 KRAS mutated samples. Kappa statistics showed that 10, 6, and 6 of the 15 ERMETIC centers had a moderate to good kappa score, when compared with external laboratory for EGFR exon 19, EGFR exon 21, and KRAS exon 2, respectively. Kappa statistics showed moderate score between centers which increased to good for EGFR exon 19 mutation when removing 16 poor-quality samples with high nonamplificable rates., Conclusions: Paraffin-embedded specimens may represent a suitable source of DNA for sequencing analyses in ERMETIC centers. EGFR exon 19 deletions were most accurately detected by ERMETIC centers. Ease and accuracy of results, depended more on the quality of sample than on the difference in molecular sequencing procedures between centers, emphasize the need of preanalytical quality control programs.

Background & Aims: Hepatocellular carcinoma (HCC) is one of the most frequent human cancers and a major cause of cancer-related death worldwide. The major risk factors for developing HCC are infection by hepatitis B virus (HBV) and hepatitis C virus (HCV), chronic alcoholism, and aflatoxins; however, critical gene targets remain largely unknown. Herein, we sought to establish DNA methylation patterns in HCC and corresponding cirrhotic tissues and to identify DNA methylation changes associated with major risk factors., Methods: We have established assays for quantitative analysis of DNA methylation levels in a panel of seven cancer-associated genes and repetitive elements, and combined these assays with a series of HCC tumors, associated with major risk factors, collected from two different geographical areas., Results: We found a high frequency of aberrant hypermethylation of specific genes (RASSF1A, GSTP1, CHRNA3, and DOK1) in HCC tumors as compared to control cirrhotic or normal liver tissues, suggesting that aberrant hypermethylation exhibits non-random and tumor-specific patterns in HCC. Importantly, our analysis revealed an association between alcohol intake and the hypomethylation of MGMT and between hypermethylation of GSTP1 and HBV infection, indicating that hypermethylation of the genes analyzed in HCC tumors exhibits remarkably distinct patterns depending on associated risk factors., Conclusions: This study identifies aberrant DNA methylation of specific cellular genes in HCC and the major risk factors associated with these changes, providing information that could be exploited for biomarker discovery in clinics and molecular epidemiology., (Copyright © 2010 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.)

Hepatocellular carcinoma (HCC) is the most frequent type of primary liver cancer and occurs mainly in patients with cirrhosis. This work aimed at reviewing the main data and trends about HCC epidemiology in France, and about prevention, screening and diagnosis in patients with chronic liver diseases. The six following research topics were considered as priorities: 1) to improve epidemiological knowledge of HCC in France; 2) to clarify the epidemiology of HCC occuring in normal liver and to identify predictive factors; 3) to prevent cancer occurrence in patients with cirrhosis; 4) to improve the knowledge of predictive factors for HCC occurrence in patients with cirrhosis; 5) to improve the diagnostic procedure of nodules below 2 cm in diameter in patients with cirrhosis; 6) to understand functioning of medical networks in order to identify the reasons for late diagnosis and treatment of HCC in patients with cirrhosis.

The presence of small amounts of tumor DNA in cell free DNA (CFDNA) circulating in the plasma or serum of cancer patients was first demonstrated 30 years ago. Since then, overall plasma DNA concentration in cancer patients and genetic or epigenetic alterations specific to tumor DNA have been investigated in patients diagnosed with different types of cancer. The proportion of patients with altered CFDNA varies with the pathology and the nature of the marker. However, several studies have reported the presence of altered CFDNA in over 50% of cancer patients, suggesting that this marker may be common and amenable for a variety of clinical and epidemiological studies. Because the mechanisms and timing of CFDNA release in the blood stream are poorly understood, only few studies have addressed the use of CFDNA for early cancer detection or as a biomarker for mutagenesis and tumourigenesis in molecular epidemiology. In this review, we discuss the technical issues involved in obtaining, using and analyzing CFDNA in cancer or healthy subjects. We also summarize the literature available on the mechanisms of CDNA release as well as on cross-sectional or prospective studies aimed at assessing the clinical and biological significance of CFDNA. These studies show that, in some circumstances, CFDNA alterations are detectable ahead of cancer diagnosis, raising the possibility of exploiting them as biomarkers for monitoring cancer occurrence. Testing these hypotheses will require well-designed studies, assessing multiple markers with quantitative and sensitive methods, with adequate follow-up of subjects, and we provide recommendations for the development of such studies.

Oesophagogastric cancer occurs in the oesophagus, the oesophagogastric region and the stomach, including the proximal and distal stomach. In 2005, the worldwide burden of oesophagogastric cancer was estimated to be 1,500,000 new cases (500,000 oesophagus and 1,000,000 stomach). Squamous cell cancer is linked with alcohol and tobacco consumption in Western countries. Its incidence is much higher in regions of Asia with a low-socio-economic status, nutritional deficiencies, poor oral status, carcinogens absorbed with smoked meat, fat-cooked foodstuffs, vegetables containing toxic alkaloids or mycotoxins, and water containing nitrites, nitrates and nitrosamines. Adenocarcinoma develops in the columnar lined oesophagus. Its incidence is still low but there is an increasing trend. The incidence of stomach cancer is decreasing worldwide, but is still high in Japan. Causal factors include Helicobacter pylori infection with atrophic gastritis and a diet poor in fruit and vegetables. Preneoplastic conditions of the oesophagogastric mucosa include erosive oesophagitis in alcoholics, columnar lined oesophagus as a complication of gastro-oesophageal reflux disease, and atrophic gastritis following H. pylori infection.

The TP63 gene is a member of the TP53 gene family. In contrast with TP53, this gene is not frequently inactivated by mutation in cancer. Initial experiments with disrupted TP63 have allowed specifying p63 protein a role in the regulation of differentiation and morphogenesis in epithelial and mesenchymal tissues. Nevertheless, there is growing evidence that p63 is also involved in oncogenesis through several mechanisms. Indeed, amplification of TP63 is detected in about 25% of squamous cell carcinomas of lung, head and neck and oesophagus. This results in overexpression of a truncated form of p63 (DeltaNp63) that may counteract growth suppression induced by full length p63 (TAp63), as well as by the other family members, p53 and TAp73. Moreover, mice heterozygous for TP63 develop spontaneous tumours. Whereas p53 plays a major role in response to numerous DNA-damaging agents, the involvement of p63 in this process is not well documented. Nevertheless, several groups recently reported that TAp63 can induce cell cycle arrest and apoptosis in DNA-damaged cells, alone or in synergy with chemotherapeutic agents, and thus appears as a chemosensitivity factor. Overall, in addition to non-redundant, specific functions in differentiation and morphogenesis, p63 appears to exert biological functions similar to those of p53 and to take a growing place in oncogenesis and modulation of responses to anti-cancer therapy.

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Several large prospective investigations are under way or are planned in different parts of the world, aiming at the investigation of gene-environment interactions for chronic diseases. Technical, practical and ethical issues are raised by such large investigations. Here we describe how such issues were approached within a case-control study nested in EPIC, a large European cohort, and the kind of validation studies that have been set up. The GenAir investigation aimed at measuring the effects of air pollution and environmental tobacco smoke on human health in EPIC with a nested design and with biological measures. Validation studies included (a) comparisons between cotinine measurements, hemoglobin adducts and questionnaire data; (b) an analysis of the determinants of DNA adduct concentration; (c) comparison among different genotyping methods; (d) an analysis of the determinants of plasma DNA amounts. We also describe how the ethical issues were dealt with in our investigation.

Due to particular social and economical development, and to the impact of globalization of lifestyles, Latin America shows a superposition of cancers that are frequent in low resource countries (gastric, oesophageal squamous cell and cervical cancers) and high resource countries (cancers of breast, colon and rectum, lung and prostate). Latin America thus offers opportunities for investigating the impact on changing lifestyle patterns on the occurrence of cancer. At the molecular level, mutations in the tumor suppressor gene TP53 are common in many cancers and their distribution can be informative of the nature of the mutagenic mechanisms, thus giving clues to cancer etiology and molecular pathogenesis. However most of the data available are derived from studies in industrialized countries. In this review, we discuss current trends on cancer occurrence in Latin American countries, and we review the literature available on TP53 mutations and polymorphisms in patients from Latin America. Overall, a total of 285 mutations have been described in 1213 patients in 20 publications, representing 1.5% of the total number of mutations reported world-wide. Except for hematological cancers, TP53 mutation frequencies are similar to those reported in other regions of the world. The only tumor site presenting significant differences in mutation pattern as compared to other parts of the world is colon and rectum. However, this difference is based on a single study with 35 patients. Recently, a characteristic TP53 mutation at codon 337 (R337H) has been identified in the germline of children with adrenocortical carcinoma in Southern Brazil. Further and better focused analyses of TP53 mutation patterns in the context of epidemiological studies, should help to improve our understanding of cancer etiology in order to develop appropriate health policies and public health programs in Latin America.

G-->T transversions in the TP53 gene are more common in lung cancers from smokers than in any other cancer except for hepatocellular carcinomas linked to aflatoxin. The high frequency of G-->T transversions in lung cancer has been attributed to the mutagenic action of cigarette smoke components, in particular polycyclic aromatic hydrocarbons (PAH). In a recent review [Mutat. Res. 508 (2002) 1-19], Rodin and Rodin have questioned the direct mutagenic action of PAH-like compounds and have suggested that other factors, such as selection of pre-existing endogenous mutations by smoke-induced stress, can better explain the excess of G-->T transversions in lung tumors. Their two main arguments against an involvement of PAH are that smoking may inhibit the repair of G-->T primary lesions on the non-transcribed strand and that lung cancer cell lines show a higher frequency of G-->T transversions than primary lung tumors suggesting that these mutations are not related to smoking. We illustrate here that both of these suggestions are incompatible with available evidence and that the abundance and sequence specificity of G-->T transversions in lung tumors is best explained by a direct mutagenic action of PAH compounds present in cigarette smoke.

We previously reported that nitric oxide (NO) released from S-nitrosoglutathione induces conformational change of the p53 tumor-suppressor protein that impairs its DNA-binding activity in vitro. We now demonstrate that MCF-7 cells preincubated in the presence of 0.5-1 mM S-nitrosoglutathione for 4 h before gamma-irradiation failed to arrest in the G1 phase of the cell cycle, whereas those gamma-irradiated without S-nitrosoglutathione exhibited a normal cell cycle arrest. The S-nitrosoglutathione-treated cells did not express the p53 target gene p21(waf-1) after gamma-irradiation, although p21(waf-1) was strongly expressed in cells irradiated in the absence of S-nitrosoglutathione. These results strongly suggest that NO impairs the function of p53 possibly via conformational change and/or amino acid modifications. On the other hand, cells incubated for 16 h in the presence of 1 mM S-nitrosoglutathione underwent apoptosis with accumulation of the pro-apoptotic protein Bax. This Bax accumulation, however, was shown to occur via a p53-independent pathway., (Copyright 2001 Academic Press.)

Adenocarcinoma of the esophagus (ADCE) with Barrett's mucosa and adenocarcinoma of the cardia (ADCC) are often reported as a single pathological entity. In this study we have used strict anatomical-pathological criteria to distinguish between these two lesions and we have investigated their differences in TP53 mutations, MDM2 gene amplification, and cytokeratin expression. DNA was extracted from the tumor areas of formalin-fixed, paraffin-embedded sections in 26 ADCC and 28 ADCE patients. TP53 mutations were detected by temporal temperature gradient electrophoresis and identified by sequencing. MDM2 amplification was assessed by differential polymerase chain reaction. The expression of cytokeratins 4, 7, and 13 was examined by immunohistochemistry. In ADCC, the male to female ratio was 1.8:1, compared to 27:1 in ADCE. Five ADCC patients had a history of other neoplasms, compared to only one ADCE patient. The two types of tumor differed in the prevalence of TP53 mutations (31% in ADCC and 50% in ADCE) and of MDM2 gene amplification (19% in ADCC and 4% in ADCE), and in the pattern of expression of cytokeratin 7 (positive in 100% of ADCE and in 41% of ADCC) and cytokeratin 13 (positive in 81% of ADCE and in 36.5% of ADCC). ADCE and ADCC differ in their clinical characteristics, in the prevalence of TP53 mutations and MDM2 amplifications, and in the patterns of cytokeratin expression. These results support the notion that ADCC and ADCE are distinct pathological entities.

The p53 protein plays diverse, complementary roles in the regulation of cell proliferation, genetic integrity and survival after exposure to various forms of genotoxic and non-genotoxic stresses. While there is considerable in vivo evidence that induction of apoptosis in response to DNA damage is an important biological response mediated by p53, the physiological role of p53 in the control of the cell cycle is still poorly understood. In this review, we first discuss evidence showing that p53 expression, protein level and activity are regulated in a cell-cycle dependent manner (by transcriptional control, control of protein stability, and changes in phosphorylation, acetylation and protein conformation). We then summarize the data available on the direct or indirect involvement of p53 in the control of cell-cycle progression in G1, S, G2 and M phases. Based on recent in vitro and in vivo data, we suggest that permanent cell-cycle arrest may represent a response to stress in cells with limited proliferative potential, which allows both genetic and tissular integrity to be preserved. We also discuss the way in which cell-cycle regulation may contribute to control p53 protein levels and activity during the normal cell cycle.

Esophageal squamous cell carcinoma (ESCC) is a frequent form of cancer that shows striking variations in geographic distribution, reflecting exposure to specific environmental factors that are still poorly defined. ESCC develops as the result of a sequence of histopathological changes that typically involves esophagitis, atrophy, mild to severe dysplasia, carcinoma in situ and finally, invasive cancer. Genetic changes associated with the development of ESCC include mutation of the p53 gene, disruption of cell-cycle control in G1 by several mechanisms (inactivation of p16MTS1, amplification of Cyclin D1, alterations of RB), activation of oncogenes (e.g., EGFR, c-MYC) and inactivation of several tumor suppressor genes. Loss of heterozygosity on chromosome 17q25 has been linked with tylosis, a rare autosomal dominant syndrome associated with high predisposition to ESCC. Whether this locus is also involved in sporadic ESCC remains to be elucidated. Chronic esophagitis is a frequent occurrence in populations at high risk of ESCC. These lesions often show focal accumulation of p53 protein and in some instances, patches of positive cells in esophagitis area at the margins of tumors were found to contain a mutation in the p53 gene. This observation is consistent with field cancerization in the esophagus and suggests that esophagitis may represent an interesting target for early detection of ESCC as well as for intervention strategies.

It has been reported that mammalian cells incubated with excess nitric oxide (NO) accumulate p53 protein but concomitantly this p53 loses its capacity for binding to its DNA consensus sequence. As nitration of tyrosine residues in various proteins has been shown to inhibit their functions, we examined whether NO nitrates tyrosine residues in p53 protein. MCF-7 cells expressing wild-type p53 were incubated with S-nitrosoglutathione for 4 h and cellular extracts were immunoprecipitated with an anti-p53 antibody. Western blot analyses of immunoprecipitates for p53 or for nitrotyrosine revealed low levels of nitrotyrosine in p53 from untreated cells. Incubation with 2 mM S-nitrosoglutathione induced a significant increase in the nitrotyrosine level in p53 protein compared to nontreated cells. These results suggest that excess NO produced in inflamed tissues could nitrate p53 protein, playing a role in carcinogenesis by impairing functions of this tumor-suppressor protein., (Copyright 2000 Academic Press.)

The first p53 gene mutation arising in a human tumor was described a decade ago by Baker et al. [S.J. Baker, E.R. Fearon, J.M. Nigro, S.R. Hamilton, A.C. Preisinger, J.M. Jessup, P. van Tuinen, D.H. Ledbetter, D.F. Barker, Y. Nakamura, R. White, B. Vogelstein, Chromosome 17 deletions and p53 gene mutations in colorectal carcinomas, Science 244 (1989) 217-221]. There are now over 10,000 mutations extracted from the published literature in the IARC database of human p53 tumor mutations [P. Hainaut, T. Hernandez, A. Robinson, P. Rodriguez-Tome, T. Flores, M. Hollstein, C.C. Harris, R. Montesano, IARC database of p53 gene mutations in human tumors and cell lines: updated compilation, revised formats and new visualization tools, Nucleic Acids Res. 26 (1998) 205-213; Version R3, January 1999]. A large and diverse collection of tumor mutations in cancer patients provides important information on the nature of environmental factors or biological processes that are important causes of human gene mutation, since xenobiotic mutagens as well as endogenous mechanisms of genetic change produce characteristic types of patterns in target DNA [J.H. Miller, Mutational specificity in bacteria, Annu. Rev. Genet. 17 (1983) 215-238; T. Lindahl, Instability and decay of the primary structure of DNA, Nature 362 (1993) 709-715; S.P. Hussain, C.C. Harris, Molecular epidemiology of human cancer: contribution of mutation spectra studies of tumor suppressor genes, Cancer Res. 58 (1998) 4023-4037; P. Hainaut, M. Hollstein, p53 and human cancer: the first ten thousand mutations, Adv. Cancer Res. 2000]. P53 gene mutations in cancers can be compared to point mutation spectra at the HPRT locus of human lymphocytes from patients or healthy individuals with known exposure histories, and accumulated data indicate that mutation patterns at the two loci share certain general features. Hypotheses regarding specific cancer risk factors can be tested by comparing p53 tumor mutations typical of a defined patient group against mutations generated experimentally in rodents or in prokaryotic and eukaryotic cells in vitro. Refinements of this approach to hypothesis testing are being explored that employ human p53 sequences introduced artificially into experimental organisms used in laboratory mutagenesis assays. P53-specific laboratory models, combined with DNA microchips designed for high through-put mutation screening promise to unmask information currently hidden in the compilation of human tumor p53 mutations.

p53 gene encodes a transcription factor with tumor suppressive properties and to date, somatic mutation of this gene is the most common genetic event in human cancer. A relational database has been developed to facilitate the retrieval and analysis of these mutations at the International Agency for Research on Cancer (IARC) and it currently contains information on over 8000 individual tumors and cell lines. Many factors may influence the detection and reporting of mutations, including selection of tumor samples, study design, choice of methods, and quality control. There is also concern that several biases may affect the way data appear in the literature. Minimizing these biases is an essential methodological issue in the development of mutation data-bases. In this paper, we review and discuss these main sources of bias and make recommendations to authors in order to minimize bias in mutation detection and reporting.

The p53 tumor suppressor gene encodes a nuclear phosphoprotein with growth inhibiting properties, which is activated in cell exposed to various forms of DNA damaging stress. The development of human cancer often involves inactivation of this suppressor through various mechanisms, including gene deletions and point mutations. Most mutations impair the specific DNA-binding capacity of p53, therefore allowing cells to proliferate in conditions where cells with intact p53 function are suppressed or eliminated. Thus, mutation of p53 may provide a selective advantage for the clonal expansion of preneoplastic or neoplastic cells. The diversity of p53 mutations provides a valuable tool to identify important sources of cancer-causing mutation in the human setting. Mutagens and carcinogens damage the genome in characteristics ways, leaving "mutagen fingerprints" in DNA. Well-characterised examples of such "fingerprints" include G: C to T: A transversions in lung cancers in association with cigarette smoke, G: C to T: A transversions at codon 249 in liver cancers in association with dietary exposure to Aflatoxin B1 (AFB1) and CC: GG to TT: AA tandem dipyrimidine transitions in skin cancers in association with UVB exposure. In addition, mutations at different codons are not functionally equivalent. The availability of crystal structures of p53 protein represents an essential development in the understanding of the functional properties of p53 mutants. In the future, it is expected that analysis of p53 mutations may provide useful information for the diagnosis, prognosis and therapy of cancer.

The p53 protein is a transcription factor activated in response to DNA-damaging agents (such as chemical or physical carcinogens) and which plays multiple role in the control of proliferation and survival of cells exposed to genotoxic stress. Recent developments in the analysis of the crystal structure of p53 help us to understand the exact role of the various domains of the protein, as well as the impact of the mutations which are frequently found in cancers. In the future, this structural approach may significantly contribute to the interpretation of the pathological consequences of p53 mutations.