Polymorphism of XRCC1 predicts overall survival of gastric cancer patients receiving oxaliplatin-based chemotherapy in Chinese population

X-ray cross-complementing family: the bridge linking DNA damage repair and cancer

Genomic instability is a common hallmark of human tumours. As a carrier of genetic information, DNA is constantly threatened by various damaging factors that, if not repaired in time, can affect the transmission of genetic information and lead to cellular carcinogenesis. In response to these threats, cells have evolved a range of DNA damage response mechanisms, including DNA damage repair, to maintain genomic stability. The X-ray repair cross-complementary gene family (XRCC) comprises an important class of DNA damage repair genes that encode proteins that play important roles in DNA single-strand breakage and DNA base damage repair. The dysfunction of the XRCC gene family is associated with the development of various tumours. In the context of tumours, mutations in XRCC and its aberrant expression, result in abnormal DNA damage repair, thus contributing to the malignant progression of tumour cells. In this review, we summarise the significant roles played by XRCC in diverse tumour types. In addition, we discuss the correlation between the XRCC family members and tumour therapeutic sensitivity.

Off-Label Use of Antineoplastic Drugs to Treat Malignancies: Evidence From China Based on a Nationwide Medical Insurance Data Analysis

Purpose: Cancer is a leading cause of morbidity and mortality worldwide. Off-label (OL) use of antineoplastic drugs to treat malignancies is prevalent. In this study, we quantified and characterized OL use of antineoplastic drugs to treat malignancies in China. Methods: This was a retrospective study using nationwide data collected from 2008 to 2010. Use of antineoplastic drugs was considered OL if they were used for indications not reflected in the package insert published by the National Medical Products Administration at the time of prescription. Descriptive analysis and Spearman rank correlation were used to evaluate the frequency and pattern of OL drug use. Results: In total, 51,382 patients with malignancies, 24 categories of antineoplastic drugs, and 77 types of malignancies treated with OL drugs were included in this study. Twenty commonly used antineoplastic drugs (ICD encoded as L01) were used OL in 10-61% of cases, and four commonly used endocrine therapy antineoplastic drugs (ICD encoded as L02) were used OL in 10-19% of cases. There was a significant negative correlation between the disease constituent ratio and the average OL use rate of antineoplastic drugs for various malignancies. In contrast, there was a significant positive correlation between the average OL use rate of antineoplastic drugs and the number of malignancies treated with OL drugs. Conclusion: This study provided information regarding OL use of antineoplastic drugs for treatment of malignancies, and showed that OL use was prevalent. In addition, uncommon malignancies were more likely to be treated with OL antineoplastic drugs. Furthermore, more commonly used antineoplastic drugs were more likely to be used OL.

Progress of Individualized Chemotherapy for Gastric Carcinoma Under the Guidance of Genetic Testing

BACKGROUND

Gastric cancer is a major malignancy that has high incidence rates worldwide. Approximately 30% of patients with gastric cancer have progressed into advanced stages at the time of diagnosis. Chemotherapy is the standard-of-care for most advanced gastric cancer and elicits variable responses among patients. Personalized chemotherapy based on genetic information of individual patients with gastric cancer has gained increasing attention among oncologists for guiding chemotherapeutic regimens.

METHODS

This review summarizes recent progress of individualized chemotherapy in gastric cancer guided by pharmacogenomics. Variable medical research search engines, such as PubMed, Google Scholar, SpringerLink and ScienceDirect, were used to retrieve related literature. Only peerreviewed journal articles were selected for further analyses.

RESULTS AND CONCLUSION

The efficiency of chemotherapy in patients with gastric cancer is not only determined by chemotherapeutic drugs but is also directly and indirectly influenced by functionally correlative genes. Individual gene alteration or polymorphism remarkably affects patients' responses to particular chemotherapy. Most studies have focused on the influence of single-gene alteration on a selected drug, and only a few works explored the interaction between therapeutics and a panel of genes. Individualized chemotherapy regimens guided by a genetic survey of a multiple-gene panel are expected to remarkably improve the treatment efficacy in patients with advanced gastric cancer and may become the new standard for personalizing chemotherapy for gastric cancer in the near future.

SNPs in predicting clinical efficacy and toxicity of chemotherapy: walking through the quicksand

In the "precision medicine" era, chemotherapy still remains the backbone for the treatment of many cancers, but no affordable predictors of response to the chemodrugs are available in clinical practice. Single nucleotide polymorphisms (SNPs) are gene sequence variations occurring in more than 1% of the full population, and account for approximately 80% of inter-individual genomic heterogeneity. A number of studies have investigated the predictive role of SNPs of genes enrolled in both pharmacodynamics and pharmacokinetics of chemotherapeutics, but the clinical implementation of related results has been modest so far. Among the examined germline polymorphic variants, several SNPs of dihydropyrimidine dehydrogenase (DPYD) and uridine diphosphate glucuronosyltransferases (UGT) have shown a robust role as predictors of toxicity following fluoropyrimidine- and/or irinotecan-based treatments respectively, and a few guidelines are mandatory in their detection before therapy initiation. Contrasting results, however, have been reported on the capability of variants of other genes as MTHFR, TYMS, ERCC1, XRCC1, GSTP1, CYP3A4/3A5 and ABCB1, in predicting either therapy efficacy or toxicity in patients undergoing treatment with pyrimidine antimetabolites, platinum derivatives, irinotecan and taxanes. While formal recommendations for routine testing of these SNPs cannot be drawn at this moment, therapeutic decisions may indeed benefit of germline genomic information, when available. Here, we summarize the clinical impact of germline genomic variants on the efficacy and toxicity of major chemodrugs, with the aim to facilitate the therapeutic expectance of clinicians in the odiern quicksand field of complex molecular biology concepts and controversial trial data interpretation.

Lack of Association between an XRCC1 Gene Polymorphism and Colorectal Cancer Survival in Thailand

BACKGROUND

Colorectal cancer (CRC) is one of the most common causes of death worldwide and in Thailand. The X-ray repair cross-complementary protein 1 (XRCC1) is required for efficient DNA repair. The effects of this gene on survival in colorectal cancer remain controversial and have not been reported in Thailand. The aim of this study was to investigate the association of the XRCC1 gene with survival of colorectal cancer patients in a Thai population.

MATERIALS AND METHODS

Data and blood samples were collected from 255 newly diagnosed and pathologically confirmed CRC patients who were recruited during the period 2002 to 2006 and whose vital status was followed up until 31 October, 2014. Real-time PCR-HRM was used for genotype identification. The Kaplan-Meier method, the log-rank test, and Cox proportional hazard regression were used to estimate cumulative survival curves and compare various survival distributions and adjusted hazard ratios.

RESULTS

Most of the cases were males, and the median age was 55 years. The median survival time was 2.43 years. The cumulative 1-, 3-, 5-, 7-, and 10 year survival rates were 76.70%, 39.25%, 26.50%, 16.60% and 3.56%, respectively. After adjustment, female gender, ages 50-59 and ≥ 60 years, tumour stage III+IV, a signet-ring cell carcinoma, and poor differentiation had significant associations with increased risk of CRC death. While the XRCC1 Arg/Arg homozygote appeared to be a risk factor for CRC death, the association was not significant.

CONCLUSIONS

The genetic variant in the XRCC1 may not be associated with the survival of CRC patients in Thailand. Further studies are needed to verify our findings.

XRCC1 Gene Polymorphism, Clinicopathological Characteristics and Stomach Cancer Survival in Thailand

BACKGROUND

Stomach cancer is one of leading causes of death worldwide. In Thailand, the incidence and mortality of stomach cancer are in the top ten for cancers. Effects of DNA repair gene X-ray repair cross complementary protein 1 (XRCC1) polymorphisms and clinicopathological characteristics on survival of stomach cancer in Thailand have not been previously reported. The aim of this study was to investigate the effects of XRCC1 gene and clinicopathological characteristics on survival of stomach cancer patients in Thailand.

MATERIALS AND METHODS

Data and blood samples were collected from 101 newly diagnosed stomach cancer cases pathologically confirmed and recruited during 2002 to 2006 and followed-up for vital status until 31 October 2012. Genotype analysis was performed using real-time PCR-HRM. The data were analyzed using the Kaplan-Meier method to yield cumulative survival curve, log-rank test to assess statistical difference of survival and Cox proportional hazard models to estimate adjusted hazard ratio.

RESULTS

The total followed-up times were 2,070 person-months, and the mortality rate was 4.3 per 100 person-months. The median survival time after diagnosis was 8.07 months. The cumulative 1-, 3-, 5-years survival rates were 40.4%, 15.2 % and 10.1 % respectively. After adjustment, tumour stage were associated with an increased risk of death (p= 0.036). The XRCC1 Gln339Arg, Arg/Arg homozygote was also associated with increased risk but statistically this was non-significant.

CONCLUSIONS

In addition to tumour stage, which is an important prognostic factor affecting to the survival of stomach cancer patients, the genetic variant Gln339Arg in XRCC1 may non-significantly contribute to risk of stomach cancer death among Thai people. Larger studies with different populations are need to verify ours findings.

Challenges of deciphering gastric cancer heterogeneity

Gastric cancer is in decline in most developed countries; however, it still accounts for a notable fraction of global mortality and morbidity related to cancer. High-throughput methods are rapidly changing our view and understanding of the molecular basis of gastric carcinogenesis. Today, it is widely accepted that the molecular complexity and heterogeneity, both inter- and intra-tumour, of gastric adenocarcinomas present significant obstacles in elucidating specific biomarkers for early detection of the disease. Although genome-wide sequencing and gene expression studies have revealed the intricate nature of the molecular changes that occur in tumour landscapes, the collected data and results are complex and sometimes contradictory. Several aberrant molecules have already been tested in clinical trials, although their diagnostic and prognostic utilities have not been confirmed thus far. The gold standard for the detection of sporadic gastric cancer is still the gastric endoscopy, which is considered invasive. In addition, genome-wide association studies have confirmed that genetic variations are important contributors to increased cancer risk and could participate in the initiation of malignant transformation. This hypothesis could in part explain the late onset of sporadic gastric cancers. The elaborate interplay of polymorphic low penetrance genes and lifestyle and environmental risk factors requires additional research to decipher their relative impacts on tumorigenesis. The purpose of this article is to present details of the molecular heterogeneity of sporadic gastric cancers at the DNA, RNA, and proteome levels and to discuss issues relevant to the translation of basic research data to clinically valuable tools. The focus of this work is the identification of relevant molecular changes that could be detected non-invasively.

Influences of ERCC1, ERCC2, XRCC1, GSTP1, GSTT1, and MTHFR polymorphisms on clinical outcomes in gastric cancer patients treated with EOF chemotherapy

This study investigated the associations between genetic polymorphisms of six genes involved in DNA repair, detoxification pathways, and fluoropyrimidine metabolism and clinical outcomes in MGC patients receiving EOF treatment. This retrospective study included 108 Chinese MGC patients receiving EOF as first-line chemotherapy. Nine single nucleotide polymorphisms (SNPs) of six genes (ERCC1 rs2298881, ERCC2 rs13181 and rs1799793, XRCC1 rs25487 and rs25489, GSTP1 rs1695, GSTT1 rs2266637, and MTHFR rs1801133 and rs1801131) were genotyped, and the associations between each SNP and clinical outcome were analyzed. XRCC1 rs25487 A allele was significantly associated with progression disease (PD) to EOF (p = 0.002), and patients with AA genotype had significantly poorer progression-free survival (PFS) (p = 0.001) and overall survival (OS) (p = 0.041) compared with patients with the G allele (GG + GA). ERCC2 rs13181 G allele was significantly associated with PD (p = 0.026), and G carriers (GG + GT) tended to have poorer PFS (p = 0.092) than TT homozygotes. ERCC2 rs1799793 GA genotype was associated with unfavorable PFS (p = 0.034) and a tendency toward poorer OS (p = 0.090) compared with GG homozygotes. Patients were categorized as either good (0 risk factors) or poor risk (≥1 unfavorable SNPs) using a prognostic index based on XRCC1 rs25487 AA, ERCC2 rs13181 (GG + GT), and ERCC2 rs1799793 GA genotypes, with median OS and PFS of 534 days, 281 days (p = 0.009) and 206 days, and 123 days (p < 0.001), respectively. These results suggest that the prognostic index comprising XRCC1 rs25487, ERCC2 rs13181, and rs1799793 polymorphisms may be a useful predictor of clinical outcomes in MGC treated with EOF.

Biomarkers for gastric cancer: Progression in early diagnosis and prognosis (Review)

Gastric cancer is one of leading causes of cancer-related mortality worldwide and is a notable disease due to its heterogeneity. Recently, numerous studies have investigated the molecular basis of gastric cancer, involving the alteration of pathogenesis, and invasion and metastasis. With the development of modern technologies, various novel biomarkers had been identified that appear to possess diagnostic and prognostic value; therefore, the present review describes our current knowledge of biomarkers for the early diagnosis and prognosis of gastric cancer. Classic biomarkers for gastric cancer diagnosis include carcinoembryonic antigen and cancer antigen 19-9, while microRNA and DNA hypomethylation are proposed as novel biomarkers. Excluding classical biomarkers, biomarkers for determining the progression and prognosis of gastric cancer focus on targeting microRNAs, epigenetic alterations and genetic polymorphisms.

The XRCC1 Arg399Gln gene polymorphism and risk of colorectal cancer: a study in Kashmir

BACKGROUND

The DNA repair gene XRCC1 Arg399Gln gene polymorphism has been found to be implicated in the development of various cancers, including colorectal cancer (CRC), in different populations. We aimed to determine any association of this polymorphism with the risk of CRC in Kashmir.

MATERIALS AND METHODS

A total of 120 confirmed cases of CRC and 146 healthy cancer free controls from the Kashmiri population were included in this study. Genotyping was carried out by the polymerase chain reaction- restriction fragment length polymorphism (PCR-RFLP) method.

RESULTS

Genotype frequencies of XRCC1 Arg399Gln observed in controls were 34.2%, 42.5% and 23.3% for GG (Arg/Arg), GA (Arg/Gln), AA( Gln/Gln), respectively, and 28.3%, 66.7% and 5% in cases, with an odds ratio (OR)=5.7 and 95% confidence interval (CI) =2.3-14.1 (p=0.0001). No significant association of Arg399Gln SNP with any clinicopathological parameters of CRC was found.

CONCLUSIONS

We found the protective role of 399Gln allele against risk to the development of CRC. The XRCC1 heterozygote status appears to be a strong risk factor for CRC development in the Kashmiri population.

Pharmacogenetics research on chemotherapy resistance in colorectal cancer over the last 20 years

During the past two decades the first sequencing of the human genome was performed showing its high degree of inter-individual differentiation, as a result of large international research projects (Human Genome Project, the 1000 Genomes Project International HapMap Project, and Programs for Genomic Applications NHLBI-PGA). This period was also a time of intensive development of molecular biology techniques and enormous knowledge growth in the biology of cancer. For clinical use in the treatment of patients with colorectal cancer (CRC), in addition to fluoropyrimidines, another two new cytostatic drugs were allowed: irinotecan and oxaliplatin. Intensive research into new treatment regimens and a new generation of drugs used in targeted therapy has also been conducted. The last 20 years was a time of numerous in vitro and in vivo studies on the molecular basis of drug resistance. One of the most important factors limiting the effectiveness of chemotherapy is the primary and secondary resistance of cancer cells. Understanding the genetic factors and mechanisms that contribute to the lack of or low sensitivity of tumour tissue to cytostatics is a key element in the currently developing trend of personalized medicine. Scientists hope to increase the percentage of positive treatment response in CRC patients due to practical applications of pharmacogenetics/pharmacogenomics. Over the past 20 years the clinical usability of different predictive markers has been tested among which only a few have been confirmed to have high application potential. This review is a synthetic presentation of drug resistance in the context of CRC patient chemotherapy. The multifactorial nature and volume of the issues involved do not allow the author to present a comprehensive study on this subject in one review.

Nucleotide excision repair related gene polymorphisms and genetic susceptibility, chemotherapeutic sensitivity and prognosis of gastric cancer

Human genomic DNA is in a dynamic balance of damage and repair. Cells employ multiple and specific repair pathways, such as nucleotide excision repair (NER), as unrepaired DNA damage has deleterious consequences and could give rise to carcinogenesis. Gene polymorphisms play a crucial role in predicting the risk and prognosis of cancer. Polymorphisms of NER-related genes could alter the ability of NER to effectively monitor and repair DNA damage, and thus may be associated with genetic susceptibility, chemotherapeutic sensitivity and prognosis of cancer. In recent years, increasing studies have focused on the association between polymorphisms of NER genes and gastric cancer, the world's fourth most common cancer and the second most common cause for cancer-related death. Here we reviewed the recent studies on the associations between polymorphisms of NER genes and gastric cancer from perspectives of genetic susceptibility, chemotherapeutic sensitivity and prognosis.

XRCC1 and XPD genetic polymorphisms and clinical outcomes of gastric cancer patients treated with oxaliplatin-based chemotherapy: a meta-analysis

This meta-analysis aimed to obtain a comprehensive and reliable assessment of the relationships between XRCC1 Arg399Gln and XPD Lys751Gln polymorphisms and the clinical outcomes of gastric cancer (GC) patients treated with oxaliplatin-based chemotherapy. The PubMed, CINAHL, Web of Science, CISCOM, EBSCO, Google Scholar, Cochrane Library, and CBM databases were searched for relevant articles published before September 1, 2013 without language restrictions. Crude odd ratios (ORs) or hazard risk (HR) [95 % confidence intervals (CI)] were calculated. Twelve clinical cohort studies were assessed with a total 1,024 GC patients treated with oxaliplatin-based chemotherapy. Our meta-analysis findings revealed that GC patients with the GA+AA (A carrier) genotypes of XRCC1 Arg399Gln showed a lower effective clinical response (CR+PR) than those with the GG (A non-carrier) genotype (OR=0.41, 95 % CI 0.20∼0.82, P=0.012). However, there was no statistically significant difference in effective clinical response between those with XPD AC+CC (C carrier) genotypes and CC (C non-carrier) genotype (OR=0.55, 95 % CI 0.28∼1.07, P=0.076). Furthermore, the GA+AA genotypes of XRCC1 Arg399Gln was associated with a worse progression-free survival (PFS) and overall survival (OS) compared with the CC genotype (PFS, HR=1.90, 95 % CI 1.12∼2.69, P<0.001; OS, HR=2.13, 95 % CI 0.79∼3.47, P=0.002, respectively). No relationships were found between XPD Lys751Gln polymorphism and both PFS and OS (all P>0.05). No publication bias was detected in this meta-analysis. Results from the current meta-analysis indicate that XRCC1 Arg399Gln polymorphism may be associated with poor clinical outcomes in GC patients treated with oxaliplatin-based chemotherapy.

Association between polymorphisms in XRCC1 gene and treatment outcomes of patients with advanced gastric cancer: a systematic review and meta-analysis

Background

Many reports have shown inconsistent results on the relationship between single nucleotide polymorphisms (SNPs) of X-ray repair cross complementing protein (XRCC1) gene and platinum-based chemotherapeutic efficacy. This meta-analysis aimed to summarize published data about the association between two SNPs of XRCC1 (Arg194Trp and Arg399Gln) and treatment outcomes of patients with advanced gastric cancer.

Methodology/Principal Findings

We retrieved the relevant articles from MEDLINE, Web of Knowledge, and the China National Knowledge Infrastructure (CNKI) databases. Studies were selected according to specific inclusion and exclusion criteria. Study quality was assessed according to the guidelines outlined by Hayden, et al. and PRISMA guidelines. We estimated the odds ratio (OR) for response rate versus no response after platinum-based chemotherapy. Progression-free survival (PFS) and overall survival (OS) were evaluated by pooled Cox proportional hazard ratios (HRs) and 95% confidence intervals (CIs). We found that none of the XRCC1 Arg194Trp and Arg399Gln polymorphisms was significantly associated with tumor response. Stratified analysis by ethnicity or sensitivity analysis also showed that XRCC1 SNPs were not related with chemotherapy response. Patients with minor variant A allele were likely to have poorer 2-year survival rate than those with G/G genotype. However, in the group of 5-year follow up, there was no significant association between the A allele and OS yet.

Conclusions/Significance

There is no evidence to support the use of XRCC1 Arg194Trp and Arg399Gln polymorphisms as prognostic predictors of TR and PFS in gastric patients treated with platinum-based chemotherapy. The relationship between minor variant A allele and OS requires further verification.

ERCC1 and ERCC2 variants predict survival in gastric cancer patients

Purpose

ERCC1 and ERCC2 play critical roles in the nucleotide excision repair pathway that effectively repairs DNA damage induced by chemotherapeutic agents. Therefore, functional single nucleotide polymorphisms (SNPs) in these genes could have an impact on clinical outcomes in cancer patients who received chemotherapy. However, few studies have simultaneously investigated the roles of ERCC1 and ERCC2 SNPs in clinical outcomes in gastric cancer patients.

Experimental Design

We genotyped by the TaqMan assay three common, potentially functional ERCC1 (rs3212986) and ERCC2 SNPs (rs13181 and rs1799793) in 360 gastric cancer patients. We used both Kaplan-Meier tests and Cox proportional hazards models to evaluate the effects of ERCC1 and ERCC2 genotypes and haplotypes on clinical outcomes.

Results

We found that, compared with ERCC2 rs1799793 GG+AG genotypes, the homozygous variant AA genotype was associated with significantly poorer overall survival (OS) (AA vs. GG+AG, log-rank P = 0.012) and significantly higher risk of death (AA vs. GG+AG, Adjusted hazards ratio [HR] 2.13; 95% CI, 1.28 to 3.56; P = 0.004). In combined analyses, patients with any one of the three unfavorable genotypes (i.e. ERCC1 rs3212986 TT, ERCC2 rs13181 GG and rs1799793 AA) had statistically significant hazards of poor prognosis (Adjusted HR, 1.54; 95% CI, 1.06 to 2.25; P = 0.025), compared with those without any unfavorable genotypes. Furthermore, the haplotype A-G-G (rs1799793/rs13181/rs3212986) had a significant impact on OS (Adjusted HR, 1.57; 95% CI, 1.11 to 2.21; P = 0.011), compared with the common haplotype G-T-G.

Conclusion

ERCC1 and ERCC2 functional SNPs may jointly affect OS in Caucasian gastric cancer patients. Additional large prospective studies are essential to confirm our findings.

Phase II study of satraplatin and prednisone in patients with metastatic castration-resistant prostate cancer: a pharmacogenetic assessment of outcome and toxicity

BACKGROUND

We assessed the effect of excision repair cross-complementing group 1 (ERCC1) and x-ray cross-complementing group 1 (XRCC1) gene polymorphisms on treatment outcomes with satraplatin and prednisone in patients with metastatic castration-resistant prostate cancer previously treated with docetaxel-based therapy.

PATIENTS AND METHODS

Twenty-four patients were enrolled in this single arm study. The primary objective was to determine if the presence of ERCC1 Asn118Asn (N118N, 500C>T, rs11615) and XRCC1 Arg399Gln (R399Q, 1301G>A, rs25487) genetic variants might be associated with an impact on progression-free survival (PFS); secondary objectives included overall response, survival, and toxicity.

RESULTS

After population stratification by race, white patients carrying heterozygous or variant genotypes at the ERCC1 C>T locus had a >3-fold longer median PFS (5.8 vs. 1.8 months; 2P = .18, adjusted) and 5-fold longer median overall survival (OS) (15.7 vs. 3.2 months; 2P = .010, adjusted) than did patients carrying only wild-type alleles. For the XRCC1 G>A variant, without regard to race, patients carrying the wild-type GG alleles had a longer PFS (9.3 months) than those carrying GA or AA alleles (2.7 months; 2P = .02). Similarly, those carrying GG alleles did not reach median OS, whereas those carrying GA or AA alleles had a median OS of 9.6 months (2P = .12, adjusted). Multivariable analysis by using Cox proportional hazards modeling demonstrated that only XRCC1 was associated with PFS.

CONCLUSIONS

To our knowledge, this is the first prospective study to date in patients with metastatic castration-resistant prostate cancer that describes predictive germline polymorphisms of ERCC1 and XRCC1 for assessing the clinical activity of satraplatin.

Genetic polymorphisms of ERCC1‑118, XRCC1‑399 and GSTP1‑105 are associated with the clinical outcome of gastric cancer patients receiving oxaliplatin‑based adjuvant chemotherapy

The aim of the present study was to determine whether specific molecular parameters may serve as predictors of treatment outcomes and toxicity of oxaliplatin (OXA)‑based chemotherapy, which is used as an adjuvant treatment in resected gastric cancer. All gastric cancer patients examined in the study received an OXA/5‑fluorouracil chemotherapeutic regimen. Genetic polymorphisms of certain platinum‑related genes were determined by the TaqMan 5' nuclease assay and direct sequencing. Relapse‑free survival (RFS), overall survival (OS) and toxicity were evaluated according to each genotype. Following adjustment for the most relevant clinical variables, excision repair cross‑complimentary group 1 (ERCC1)‑118 and X-ray repair cross-complementing protein 1 (XRCC1‑399) demonstrated significant predictive value for RFS and OS. We also demonstrated that carrying at least one variant XRCC1 Arg399Gln or glutathione S-transferase π 1 (GSTP1) Ile105Val allele significantly increased the risk of any grade 3 or 4 hematological toxicity. In particular, carrying at least one variant GSTP1 Ile105Val allele was also significantly correlated with an increased risk of grade 3 or 4 gastrointestinal toxicity and neurotoxicity. Our data suggested that gastric cancer patients harboring ERCC1‑118 C/C and XRCC1‑399 A/G or A/A genotypes may benefit from receiving OXA‑based adjuvant chemotherapy, and carrying at least one variant XRCC1 Arg399Gln or GSTP1 Ile105Val allele may contribute to the occurrence of adverse drug effects associated with OXA‑based chemotherapy.

DNA repair polymorphisms and treatment outcomes of patients with malignant mesothelioma treated with gemcitabine-platinum combination chemotherapy

INTRODUCTION

Genetic polymorphisms that affect DNA repair capacity can modulate the efficacy and toxicity of cytotoxic agents. Therefore, the aim of our study was to evaluate the influence of genetic variability in DNA repair genes on treatment outcome in patients with malignant mesothelioma (MM) treated with gemcitabine-platinum combination chemotherapy.

METHODS

In total, 109 patients with MM were genotyped for 10 polymorphisms in XRCC1, NBN, RAD51, and XRCC3 genes. The influence of selected polymorphisms on tumor response and occurrence of treatment-related toxicity was determined by logistic regression analysis, whereas their influence on survival was estimated by Cox proportional hazards model.

RESULTS

There were no associations between the investigated polymorphisms and tumor response, but we observed a significant association between XRCC1 399Gln allele and reduced overall survival (hazards ratio = 1.70; 95% confidence interval [CI] 1.06-2.73; p = 0.028). Interaction between XRCC1 399Gln allele and C-reactive protein levels revealed that carriers of at least one XRCC1 399Gln allele with C-reactive protein levels above median had significantly shorter overall survival time compared with other patients (12.9 months versus 25.3 months, log-rank p < 0.001). We also observed an association between XRCC1 399Gln and lower frequency of leukopenia (odds ratio [OR] = 0.25; 95% CI 0.09-0.67; p = 0.006), neutropenia (OR = 0.24; 95% CI 0.09-0.68; p = 0.007), and thrombocytopenia (OR = 0.27; 95% CI 0.09-0.84; p = 0.024). In addition, NBN 3474A>C, XRCC3 -316A>G, and Thr241Met polymorphisms showed significant associations with treatment-related toxicity.

CONCLUSIONS

Our results support the hypothesis that DNA repair gene polymorphisms, particularly XRCC1 Arg399Gln, may modify the response to gemcitabine-platinum combination chemotherapy and, for the first time, show this effect in patients with MM.

DNA repair gene polymorphism associated with sensitivity of lung cancer to therapy

This study aimed to investigate association between single-nucleotide polymorphisms (SNPs) of excision repair cross-complementing gene 1 (ERCC1), excision repair cross-complementing gene 2 (ERCC2), and X-ray repair cross-complementing group 1 (XRCC1) with sensitivity of advanced non-small cell lung cancer (NSCLC) patients to platinum-based chemotherapy. A total of 89 NSCLC patients were recruited and treated with two cycles of platinum-based chemotherapy. DNA was extracted from peripheral lymphocytes for detection of SNPs of ERCC1 Asn118Asn, ERCC2 Lys751Gln, and XRCC1 Arg399Gln. The overall response rate of these patients was 29.2%. There was no statistically significant difference of treatment response between the wild genotypes and the variant genotypes for the ERCC1 Asn118Asn and ERCC2 Lys751Gln gene. The distributions of genotypes XRCC1 Arg399Gln differed significantly between the response and non-response groups (76.9 vs. 23.1%, P = 0.001). The XRCC1 399Arg/Arg genotype carriers had a higher response rate than that of the Gln genotype carriers (OR = 4.81, 95%CI = 1.778-13.013, P = 0.002). The combination of the favorable genotypes of ERCC1, ERCC2, and XRCC1 had a higher response rate compared to that of patients with other genotypes. The combined polymorphisms of ERCC1, ERCC2, and XRCC1 may be associated with sensitivity of NSCLC to platinum-based chemotherapy. Further studies will verify these SNPs as biomarkers for prediction of platinum-based chemotherapy responses of NSCLC patients.

An XRCC1 polymorphism is associated with the outcome of patients with lymphoma undergoing autologous stem cell transplant

High-dose chemotherapy supported by autologous stem cell transplant (ASCT) remains the treatment of choice for patients with lymphoma failing first-line chemotherapy. Recent evidence suggests a relationship between the genetic variations in genes involved in DNA repair and the outcome of patients with a number of malignancies. In this work, we retrospectively evaluated the influence of an XRCC1 polymorphism (rs25487) on the treatment results in a series of 73 patients with lymphoma subjected to ASCT. The factors correlated to overall survival were the disease status at transplant and XRCC1 genotype. Carriers of a mutant A allele had a two-fold higher risk of death than those with the wild-type genotype. In addition, patients harboring one or two copies of the A allele (GA/AA) were 4.5-fold more likely to develop therapy-related acute myeloid (t-AML). Thus, the cumulative probability of t-AML at 10 years was 37 ± 13% in patients with the mutant A allele as compared to 8.5 ± 6% in the remaining cases (p = 0.04). Our findings suggest that genetic variation in the DNA repair gene XRCC1 may play a role in the results of transplant in patients with lymphoma.

ERCC1 and ERCC2 polymorphisms predict clinical outcomes of oxaliplatin-based chemotherapies in gastric and colorectal cancer: a systemic review and meta-analysis

PURPOSE

Nucleotide excision repair (NER) modulates platinum-based chemotherapeutic efficacy by removing drug-produced DNA damage. To summarize published data on the association between polymorphisms of NER genes (ERCC1 and ERCC2) and responses to oxaliplatin-based chemotherapies, we carried out a meta-analysis of gastric and colorectal cancer for commonly studied polymorphisms ERCC1 rs11615C>T and ERCC2 rs13181T>G.

PATIENTS AND METHODS

In 17 previously published studies, 1,787 cancer patients were treated with the oxaliplatin-based regimen. Primary outcomes included therapeutic response (TR; i.e., complete response + partial response vs. stable disease + progressive disease), progression-free survival (PFS), and overall survival (OS). We calculated OR or HR with 95% CIs to estimate the risk or hazard.

RESULTS

We found consistent and clinically substantial risk or hazard for TR, PFS, and OS in the oxaliplatin-treated gastric and colorectal cancer patients with an ethnic discrepancy. For ERCC1 rs11615C>T, the T allele was associated with reduced response and poor PFS and OS in Asians (TR: OR = 0.53 and 95% CI = 0.35-0.81; PFS: HR = 1.69 and 95% CI = 1.05-2.70; and OS: HR = 2.03 and 95% CI = 1.60-2.59). For ERCC2 rs13181T>G, the G allele was associated with reduced response and poor PFS and OS in Caucasians (TR: OR = 0.56 and 95% CI = 0.35-0.88; PFS: HR = 1.41 and 95% CI = 1.02-1.95; and OS: HR = 1.42 and 95% CI = 1.11-1.81).

CONCLUSIONS

NER ERCC1 rs11615C>T and ERCC2 rs13181T>G polymorphisms are useful prognostic factors in oxaliplatin-based treatment of gastric and colorectal cancer. Larger studies and further clinical trials are warranted to confirm these findings.

CYP2A6 and ERCC1 polymorphisms correlate with efficacy of S-1 plus cisplatin in metastatic gastric cancer patients

Background:

We evaluated the association between polymorphisms of cytochrome P450 2A6 (CYP2A6)/excision repair cross-complementation group 1 (ERCC1)/X-ray repair cross-complementing group 1(XRCC1) and treatment outcomes of metastatic gastric cancer (MGC) patients treated with S-1/cisplatin.

Methods:

Among MGC patients (n=108), who received S-1 (40 mg m⁻² b.i.d., days 1–14) and cisplatin (60 mg m⁻², day 1) every 3 weeks, we analysed the wild-type allele (W) and variants (V) of CYP2A6 (*4, *7, *9, *10), and the polymorphisms of ERCC1 (rs11615, rs3212986) and XRCC1 (rs25487).

Results:

Patients having fewer CYP2A6 variants had better response rates (W/W vs W/V other than *1/*4 vs V/V or *1/*4=66.7 vs 58.3 vs 32.3% P=0.008), time to progression (TTP) (7.2 vs 6.1 vs 3.5 months, P=0.021), and overall survival (23.2 vs 15.4 vs 12.0 months, P=0.004). ERCC1 19442C>A (rs3212986) was also associated with response rate (C/C, 46.7% vs C/A, 55.3% vs A/A, 87.5%) (P=0.048) and TTP (4.4 vs 7.6 vs 7.9 months) (P=0.012). Patients carrying both risk genotypes of CYP2A6 (V/V or 1/*4) and ERCC1 19442C>A (C/C) vs those carrying none showed an adjusted odds ratio of 0.113 (P=0.004) for response, and adjusted hazard ratios of 3.748 (P=0.0001) for TTP and 2.961 (P=0.006) for death.

Conclusion:

Polymorphisms of CYP2A6 and ERCC1 19442C>A correlated with the efficacy of S-1/cisplatin.

Translational medicine and reliability of single-nucleotide polymorphism studies: can we believe in SNP reports or not?

BACKGROUND

The number of genetic association studies is increasing exponentially. Nonetheless, genetic association reports are prone to potential biases which may influence the reported outcome.

AIM

We hypothesized that positive outcome for a determined polymorphism might be over-reported across genetic association studies analysing a small number of polymorphisms, when compared to studies analysing the same polymorphism together with a high number of other polymorphisms.

METHODS

We systematically reviewed published reports on the association of glutathione s-transferase (GST) single-nucleotide polymorphisms (SNPs) and cancer outcome.

RESULT

We identified 79 eligible trials. Most of the studies examined the GSTM1, theGSTP1 Ile105Val mutation, and GSTT1polymorphisms (n = 54, 57 and 46, respectively). Studies analysing one to three polymorphisms (n = 39) were significantly more likely to present positive outcomes, compared to studies examining more than 3 polymorphisms (n=40) p = 0.004; this was particularly evident for studies analysing the GSTM1polymorphism (p =0.001). We found no significant associations between journal impact factor, number of citations, and probability of publishing positive studies or studies with 1-3 polymorphisms examined.

CONCLUSIONS

We propose a new subtype of publication bias in genetic association studies. Positive results for genetic association studies analysing a small number of polymorphisms (n = 1-3) should be evaluated extremely cautiously, because a very large number of such studies are inconclusive and statistically under-powered. Indeed, publication of misleading reports may affect harmfully medical decision-making and use of resources, both in clinical and pharmacological development setting.

Biomarker analysis in patients with advanced gastric cancer treated with S-1 plus cisplatin chemotherapy: orotate phosphoribosyltransferase expression is associated with treatment outcomes

This study was performed to analyze the impact of protein expression related to fluoropyrimidine and cisplatin metabolism (thymidylate synthase, dihydropyrimidine dehydrogenase, thymidine phosphorylase, orotate phosphoribosyltransferase [OPRT], excision repair cross-complementation 1, Fanconi anemia complementation group D2, glutathione S-transferase P1, and X-ray repair cross-complementing group 1) on treatment outcomes in patients with metastatic or relapsed gastric cancer (MRGC) receiving S-1/cisplatin chemotherapy. Protein expression was measured by immunohistochemistry (IHC). Of the 43 patients who had received S-1 (80 mg/m2/day; days 1-14) and cisplatin (60 mg/m2; day 1) every 3 weeks and had available tissue blocks, IHC was successfully performed in 41 patients. Patients with high OPRT levels in tumor tissues (IHC score≥6) had superior progression-free survival (PFS) (23.3 vs. 14.1 weeks [median]) and overall survival (OS) (72.4 vs. 55.4 weeks [median]) to those with low OPRT levels (IHC score≤5; P-values<.05). Expression levels of other proteins were not predictive of treatment outcomes. In multivariate analysis, both a good performance status and a high OPRT level were independently associated with prolonged PFS and OS. The OPRT expression level may be a good predictive marker in S-1/cisplatin-treated patients with MRGC.

Genetic polymorphisms in DNA repair genes XPC, XPD, and XRCC4, and susceptibility to Helicobacter pylori infection-related gastric antrum adenocarcinoma in Guangxi population, China

Genetic polymorphisms in DNA repair genes may influence individual variation in DNA repair capacity, which may be associated with risk of gastric antrum adenocarcinoma (GAA) related to Helicobacter pylori infection. This study, including 361 GAAs and 616 controls without any evidence of tumors, was designed to evaluate the association between the polymorphisms of DNA repair genes XPC Ala499Val (RS#2228000) and Lys939Gln (RS#2228001), XPD Lys751Gln (RS#13181), and XRCC4 Ala247Ser (RS#3734091) and Ser298Asn (RS#1805377), and GAA risk for Guangxi population by means of TaqMan-PCR analysis. Increased risks of GAA were found for individuals with H. pylori positive [odds ratio (OR), 2.48; 95% confidence interval (CI), 1.84-3.33] or cagA positive (OR, 7.34; 95% CI, 5.46-9.87). No differences were observed among the studied groups with regard to the genotype distribution of XPC codons 499 and 939 and of XRCC4 codon 247; but XPD codon 751 genotypes with Gln [ORs (95% CI) were 2.67 (1.98-3.58) and 3.97 (2.64-5.99) for Lys/Gln and Gln/Gln, respectively] and XRCC4 codon 298 genotypes with Asn [ORs (95% CI) were 3.01 (2.21-4.10) and 4.78 (3.24-7.05) for Ser/Asn and Asn/Asn, respectively] increased the risk of GAA. Interestingly, there was an interactive effect between the risk genotypes of these two genes and cagA-positive status in the GAA risk (OR(interact) = 2.05 and 2.08, respectively). However, we did not find the gene-H. pylori-status interaction effects on the risk of GAA (P(interact) > 0.05). The results suggested that the polymorphisms of XPD codon 751 and XRCC4 codon 298 are associated with an increased risk of developing H. pylori-related GAA among Guangxi population.

Genetic polymorphism of GSTP1: prediction of clinical outcome to oxaliplatin/5-FU-based chemotherapy in advanced gastric cancer

The aim of this study was to evaluate the predictive value of the polymorphism Glutathione S-transferase P1 (GSTP1) Ile(105)Val on oxaliplatin/5-FU-based chemotherapy in advanced gastric cancer. Patients with advanced gastric cancer accepted oxaliplatin/5-FU-based chemotherapy as first-line chemotherapy were investigated. GSTP1 Ile(105)Val polymorphism was detected by TaqMan-MGB probe allelic discrimination method. Response to treatment was assessed by disease controlled rate. Time to progression, overall survival and toxicities were recorded. Final patient outcomes were as follows: the allele frequencies of GSTP1 were (105)Ile/(105)Ile 52%, (105)Ile/(105)Val 41% and (105)Val/(105)Val 7%. For patients with (105)Ile/(105)Ile and those with at least one (105)Val allele, disease control rate was 39% and 71% (P=0.026), respectively; median time to progression was 4.0 and 7.0 months (P=0.002); median overall survival time was 7.0 and 9.5 months (P=0.002). Neurological toxicity was more frequently occurred in patients with two (105)Ile alleles (P=0.005). In conclusion, patients with at least one (105)Val allele have better prognosis and response to oxaliplatin/5-FU-based regimen as first-line treatment for patients with advanced gastric cancer.

BRCA1 and XRCC1 polymorphisms associated with survival in advanced gastric cancer treated with taxane and cisplatin

This study evaluated the influence of genetic polymorphism influencing drug metabolism on survival in taxane- and cisplatin-treated advanced gastric cancer (AGC). Peripheral blood samples from 207 AGC patients treated with first-line chemotherapy of taxane and cisplatin were used. We investigated polymorphisms that influenced the metabolism of taxane (ATP-binding cassette transporter B1 (ABCB1)), cisplatin (glutathione S-transferase M1 (GSTM1), glutathione S-transferase P1 (GSTP1), glutathione S-transferase T1 (GSTT1), excision repair cross complementing 1 (ERCC1), X-ray Cross Complementing group 3 (XRCC3), X-ray Cross Complementing group 4 (XRCC4), X-ray Cross Complementing group 1 (XRCC1), breast cancer (BRCA1)), and 5-fluorouracil (methylene tetrahydrofolate reductase (MTHFR), thymidylate synthase (TYMS)). A total of 207 patients were enrolled between May 2004 and Dec 2008, and 200 patients were analyzed. The overall response rate was 38.5%. Time to progression and overall survival time were 4.3 +/- 0.19 months and 11.9 +/- 1.05 months, respectively. There was no significant association between genetic polymorphism and response rate. However, the BRCA1 mutant TT homozygote was associated with significant prolongation of overall survival (hazard ratio [HR] = 0.43; 95% confidence interval [CI], 0.20-0.92; P = 0.03) and progression-free survival (HR = 0.51; 95% CI, 0.26-1.00; P = 0.05). Also, the XRCC1 194 CT genotype was associated with inferior overall survival, relative to the XRCC1 194 CC homozygotes (HR = 1.49; 95% CI, 0.11-2.07; P = 0.018).These findings suggest that BRCA1 TT and XRCC1 194 CT genotypes could be modest prognostic markers of AGC response in taxane- and cisplatin-treated patients.

The combination of ERCC1 and XRCC1 gene polymorphisms better predicts clinical outcome to oxaliplatin-based chemotherapy in metastatic colorectal cancer

PURPOSE

To evaluate the effect of excision repair cross-complementing group 1 (ERCC1) and X-ray cross-complementing group 1 (XRCC1) gene polymorphisms on treatment outcome in patients receiving oxaliplatin-based regimens for metastatic colorectal cancer.

METHODS

Hundred and thirteen patients with a diagnosis of metastatic colorectal cancer were treated with oxaliplatin-based chemotherapy. ERCC1 codon 118C/T and XRCC1 codon 399A/G polymorphisms were tested by real-time polymerase chain reaction (RT-PCR) method in peripheral blood lymphocytes of these patients. Disease control rates and survivals were compared by types of genotypes.

RESULTS

Analyses of the patterns of the polymorphism located at ERCC1 codon 118 showed that 55 (48.67%) patients were homozygous for C/C genotype, 15 (13.27%) were homozygous for the T/T genotype, and 43 (38.06%) were heterozygous for C/T genotype. Analyses of the polymorphism located at XRCC1 codon 399 showed that 61 (53.98%) patients were homozygous for A/A genotype, 13 (11.50%) were homozygous for the G/G genotype, and 39 (34.52%) were heterozygous for A/G genotype. After two cycles of chemotherapy, there was complete response (CR) in 1 patient, partial response (PR) in 24 patients, and stable disease (SD) in 56 patients. Altogether in 81 (71.68%) patients the disease was controlled after chemotherapy. Thirty-two (28.32%) patients showed disease progression. After adjusting for some clinical factors, both the ERCC1 polymorphism and the XRCC1 polymorphism lost their roles in predicting DCR (P = 0.662, P = 0.631) and MST (P = 0.692, P = 0.572). But the combination of ERCC1 and XRCC1 polymorphisms was significantly associated with DCR (P = 0.01) and MST (P = 0.000) independently.

CONCLUSIONS

This is the first study which showed that polymorphisms of ERCC1 and XRCC1, in combination not individually, were independent predictors for DCR and OS. This may contribute to the selection of patients who would benefit from oxaliplatin-based chemotherapy for metastatic colorectal cancer.

Polymorphisms in p53, GSTP1 and XRCC1 predict relapse and survival of gastric cancer patients treated with oxaliplatin-based adjuvant chemotherapy

PURPOSE

The aim of this study was to assess whether genetic polymorphisms in p53, glutathione S-transferase P1 (GSTP1), GSTM1, excision repair cross complementing group 1 (ERCC1) and X-ray repair cross-complementing group 1 (XRCC1) genes are associated with clinical outcome of gastric cancer patients treated with oxaliplatin-based adjuvant chemotherapy.

METHODS

The genetic polymorphisms in p53, GSTP1, GSTM1 (null), ERCC1 and XRCC1 were determined in 102 gastric cancer patients treated with oxaliplatin-based adjuvant chemotherapy using polymerase chain reaction-ligation detection reaction method.

RESULTS

Among the five studied polymorphisms, p53 codon 72 Pro/Pro, GSTP1 codon 105 Ile/Ile, and XRCC1 codon 399 Gln/Gln + Arg/Gln were associated with poor relapse-free survival and overall survival (P < 0.05); and the prognostic effect was retained in the Cox multivariate analysis. Combination analysis with the three polymorphisms using the Kaplan-Meier method and Cox multivariate analysis revealed that the relapse-free and overall survivals significantly increase with the number of favorable genotypes (P < 0.05). No significant association was found between the GSTM1 (null) or the ERCC1 codon 118 genotypes and the clinical outcome (P > 0.05).

CONCLUSION

Testing for p53 Arg72Pro, GSTP1 Ile105Val, and XRCC1 Arg399Gln polymorphisms may allow identification of gastric cancer patients who will benefit from oxaliplatin-based adjuvant chemotherapy. Selecting specific adjuvant treatments according to the individual genetic background may represent an innovative strategy that warrants prospective studies.

GSTP1 determines cis-platinum cytotoxicity in gastric adenocarcinoma MGC803 cells: regulation by promoter methylation and extracellular regulated kinase signaling

Detoxification mechanisms can play a pivotal role in determining tumor cell responses to platinum-based chemotherapy. Glutathione S-transferase-pi (GSTP1) belongs to a supergene family of detoxifying enzymes involved in the prevention of DNA damage and subsequent platinum resistance in numerous cancers. The role of GSTP1 in gastric cancer sensitivity to chemotherapy is, however, not known. In this study, we found that the human gastric cancer cell line MGC803 was significantly more sensitive to cis-platinum (CDDP) than the other gastric cancer lines examined (BGC823 and SGC7901). To explore the potential role of GSTP1 in drug resistance, we measured GSTP1 expression in these cells. GSTP1 mRNA and protein were not detectable in MGC803 cells; both were present in BGC823 and SGC7901 cells. GSTP1 CpG island DNA methylation was examined. We report that promoter hypermethylation was associated with the absence of GSTP1 expression in MGC803 cells. Treatment of these cells with 5-aza-2'-deoxycytidine, a DNA methyltransferase inhibitor, restored GSTP1 expression and suppressed sensitivity to CDDP. The selective mitogen-activated protein kinase/extracellular regulated kinase (ERK) pathway inhibitor PD98059 decreased GSTP1 expression in 5-aza-2'-deoxycytidine-treated cells. A similar decrease was observed in the BGC823 and SGC7901 cell lines, suggesting that mitogen-activated protein kinase/ERK signaling stimulates GSTP1 expression. CDDP sensitivity was also enhanced by PD98059. These observations indicate that somatic promoter hypermethylation and impaired ERK signaling are associated with decreased GSTP1 expression and CDDP sensitivity in gastric cancer cell lines. Evaluation of promoter methylation and ERK activity may be useful for predicting tumor sensitivity to platinum-based chemotherapeutics.

Pharmacogenetics in chemotherapy of colorectal cancer

Although in recent years, chemotherapeutic options for colorectal carcinoma have expanded, overall response rates are still too low, with high rates of toxicity. Pharmacogenetics aim at predicting both treatment response and adverse effects in individual patients. This review describes the current knowledge of pharmacogenetic markers in the systemic treatment of colorectal cancer. UGT1A1*28 leads to reduced conjugation of SN-38, the active metabolite of irinotecan, resulting in an increased rate of adverse effects, especially neutropenia. To a lesser extent, increased 5-FU toxicity is predicted by DPYD*2A. A variable number of tandem repeats polymorphism in the thymidylate synthase enhancer region, in combination with a single nucleotide polymorphism C>G, may predict poorer response to 5-FU. Efficacy of oxaliplatin is influenced by polymorphisms in components of DNA repair systems, such as ERCC1 and XRCC1. Polymorphic changes in the endothelial growth factor receptor probably predict cetuximab efficacy. Furthermore, the antibody-depended cell-mediated cytotoxic effect of cetuximab may be reduced by polymorphisms in the immunoglobin G fragment C receptors. Bevacizumab efficacy is suspected to be influenced by polymorphisms in the VEGF gene and the hypoxia inducible factor 1alpha gene. Although the interpretation of pharmacogenetic studies is complicated, results imply a promising way of pretreatment prediction of chemotherapy efficacy and toxicity.

Pharmacogenetic analyses of a phase III trial in metastatic gastroesophageal adenocarcinoma with fluorouracil and leucovorin plus either oxaliplatin or cisplatin: a study of the arbeitsgemeinschaft internistische onkologie

PURPOSE

To evaluate the association of germ-line polymorphisms of genes that may impact treatment outcome of platinum and fluorouracil combination chemotherapy in advanced gastric cancer (AGC).

PATIENTS AND METHODS

Blood samples of 156 patients enrolled onto a phase III study comparing fluorouracil, leucovorin, and oxaliplatin with fluorouracil, leucovorin, and cisplatin were collected. Polymorphisms within genes of TS, MTHFR, MTR, OPRT, XPD, ERCC1, XRCC1, XPA, GSTP1, GSTT1, and GSTM1 were genotyped using polymerase chain reaction-based techniques.

RESULTS

Median overall survival (OS) was 11.8 months (95% CI, 9.75 to 13.79 months) and median progression-free survival (PFS) was 5.8 months (95% CI, 4.99 to 6.61 months). The TS-3R/+6 haplotype (P = .004), the GSTT1 deletion polymorphism (P = .015), and genotypes of OPRT-Gly213Ala (P = .003) and XRCC1-Arg399Gln (P = .023) could be identified as independent predictors of OS. For PFS analyses, the TS-3R/+6 haplotye (P = .003) and MTR-A2756G (P = .01) were identified as independent positive predictors. The association between the GSTT1 deletion polymorphism and PFS showed only borderline significance (P = .053). Treatment related hematotoxicity in terms of grade 3/4 leukopenia was lowest among TS-3R/+6 haplotype carriers (P = .037). Grade 3/4 neutropenia was directly associated with the MTR-2756G/G genotype (P = .011), GSTP1-105Ile/Ile genotype (P = .02), and with the ERCC1-118T/8092C-haplotype (P = .042). In addition, significant associations between GSTP1-105Ile/Ile genotype and neurotoxicity and between the XPD-Asn312/751Gln haplotype and nephrotoxicity could be identified (P = .028 and P = .005, respectively).

CONCLUSION

These findings underline the hypothesis that germ-line polymorphisms may play an important role in individualizing chemotherapy in AGC and deserve further prospective evaluation in AGC patients.