A nucleotide polymorphism in ERCC1 in human ovarian cancer cell lines and tumor tissues

ERCC1 rs11615 polymorphism and chemosensitivity to platinum drugs in patients with ovarian cancer: a systematic review and meta-analysis

OBJECTIVE

To explore the relationship between ERCC1 rs11615 polymorphism and chemosensitivity to platinum drugs in ovarian cancer by the method of meta-analysis.

METHODS

Pubmed, Web of Science, EMBASE, Cochrane Library, China National Knowledge Infrastructure (CNKI), and China Wanfang databases were comprehensively searched up to September 2020, to identify the relationship between ERCC1 rs11615 polymorphism and chemosensitivity of ovarian cancer. The data was analyzed by Stata 15.0 statistic software.

RESULTS

A total of 10 published papers were included, including 1866 patients with ovarian cancer. The results showed that compared allele C at ERCC1 rs11615 locus with allele T, the pooled OR was 0.92 (95%CI:0.68 ~ 1.24, P > 0.05). There were no significant differences in recessive, dominant, homozygous, and heterozygous models. In accordance with a subgroup analysis of Ethnicity, all genotypes were statistically significant in the Asian population. In the allelic, dominant, recessive, homozygous and heterozygous models, the OR was 0.70 (95%CI:0.51 ~ 0.95), 0.20 (95%CI:0.07 ~ 0.56), 0.79 (95%CI:0.63 ~ 1.00), 0.21 (95%CI:0.07 ~ 0.59), 0.19 (95%CI:0.07 ~ 0.54), respectively, while in the Caucasian population, no statistically significant genotype was found.

CONCLUSION

The ERCC1 rs11615 polymorphism is associated with chemosensitivity in patients with ovarian cancer, especially in the Asian population, but not in the Caucasian population.

The ECCR1 rs11615, ERCC4 rs2276466, XPC rs2228000 and XPC rs2228001 polymorphisms increase the cervical cancer risk and aggressiveness in the Bangladeshi population

Background

Multiple studies around the world revealed that genetic polymorphism in different genes of the DNA repair system might affect the DNA repair capabilities and accelerate the chances of cervical cancer (CC) development. Therefore, we aimed to evaluate the association of DNA repair gene- ECCR1 rs11615, ERCC4 rs2276466, XPC rs2228000 and rs2228001 polymorphisms and CC susceptibility in the Bangladeshi population.

Methods

A case-control genetic association study was conducted among 210 patients with diagnostically confirmed CC and 200 healthy volunteers. The p-value and OR (odds ratios) with 95% CI (confidence interval) were evaluated to get the level of association.

Results

After the individual analysis of all SNPs, we noticed that ECCR1 rs11615 possessed a significantly lower risk, whereas ERCC4 rs2276466 possessed a significantly elevated risk of CC in all genetic models (p < 0.05). XPC rs2228000 showed a significantly lower risk of CC in TC, TC + CC genotypes and allele model (OR = 0.61, p = 0.025; OR = 0.61, p = 0.019 and OR = 0.67, p = 0.027, respectively), whereas XPC rs2228001 possessed a significantly elevated risk of CC in CA, CA + AA genotypes and allele model (OR = 1.67, p = 0.012; OR = 1.69, p = 0.009 and OR = 1.42, p = 0.022). Besides, ERCC4 rs2276466 (Grade III vs. I + II: OR = 4.01, p = 0.003) and XPC rs2228001 (Grade III vs. I + II: OR = 3.38, p = 0.003) were connected with high tumor aggressiveness and ERCC4 rs2276466 was also showed a lower risk of CC development in the younger population (<45 years).

Conclusion

The findings supported that rs2276466 and rs2228001 polymorphisms increase CC development and aggressiveness, whereas rs11615 and rs2228000 lower the CC risk in the studied population.

Clinical Perspectives of ERCC1 in Bladder Cancer

ERCC1 is a key regulator of nucleotide excision repair (NER) pathway that repairs bulky DNA adducts, including intrastrand DNA adducts and interstrand crosslinks (ICLs). Overexpression of ERCC1 has been linked to increased DNA repair capacity and platinum resistance in solid tumors. Multiple single nucleotide polymorphisms (SNPs) have been detected in ERCC1 gene that may affect ERCC1 protein expression. Platinum-based treatment remains the cornerstone of urothelial cancer treatment. Given the expanding application of neoadjuvant and adjuvant chemotherapy in locally advanced bladder cancer, there is an emerging need for biomarkers that could distinguish potential responders to cisplatin treatment. Extensive research has been done regarding the prognostic and predictive role of ERCC1 gene expression and polymorphisms in bladder cancer. Moreover, novel compounds have been recently developed to target ERCC1 protein function in order to maximize sensitivity to cisplatin. We aim to review all the existing literature regarding the role of the ERCC1 gene in bladder cancer and address future perspectives for its clinical application.

Study of the Relationship between ERCC1 Polymorphisms and Response to Platinum-based Chemotherapy in Iranian Patients with Colorectal and Gastric Cancers

This study was designed to evaluate the effect of excision repair cross complementing group 1 (ERCC1) rs11615 codon 118C/T gene polymorphisms on treatment outcomes in Iranian patients receiving oxaliplatin-based regimens for colorectal (CRC) and gastric cancers (GC). Patients, who were candidates to receive oxaliplatin-based chemotherapy, entered into the study. In 2-week intervals, the patients received combination regimen of oxaliplatin, fluorouracil, and leucovorin (FOLFOX) for 3 months. ERCC1 rs11615 codon 118C/T polymorphism was tested by restriction fragment length polymorphism polymerase chain reaction (RFLP-PCR) method using patients’ peripheral blood lymphocytes. The tumor response to chemotherapy was evaluated by examining the size of the tumor using CT scan. Association between response rates, according to the RECIST criteria, and patients’ genotypes was evaluated. Any relationship between response rate and possible explanatory factors was also determined. Overall, 40 patients (13 females (32.5%), and 27 males (67.5%)) enrolled in the study. Four patients (10.0%) carried the homo­zygous mutation (T/T genotype), ten patients (25.0%) were heterozygous (C/T genotype), and twenty-six patients (65%) were homo­zygous (C/C genotype). Response rate were 30.77%, 20.00%, and 0.00% for the genotypes C/C, C/T, and T/T, respectively. No significant association between response rate and genotypes was observed (p = 0.64). Patients with well- and moderately-differentiated histological grade of the tumor showed a better response rate (100.00% of 2 patients and 66.66% of 12 patients, respectively) compared to those with poorly differentiated (0.00% of 26 patients) histological grade (p < 0.001). Further multicenter studies are recommended to confirm conclusively our findings.

Role of common ERCC1 polymorphisms in cisplatin-resistant epithelial ovarian cancer patients: A study in Chinese cohort

Epithelial ovarian cancer (EOC) contributes the majority of death cases among various ovarian malignancies. Although a standard method of treatment is the surgical removal of malignant tissue followed by platinum-based chemotherapy, a group of patients does not respond appropriately to cisplatin. An appropriate response to cisplatin has been linked with the nucleotide excision repair mechanism. The present study aims to investigate the role of polymorphisms in DNA repair genes, excision repair cross-complementation group 1 (ERCC1) with susceptibility to EOC development and tumour response to platinum-based chemotherapy in Chinese EOC patients. Patients (n = 559) reporting to the Department of Oncology and general surgery, the First Affiliated Hospital of Kunming Medical University, were enrolled in the study. Three hundred twenty-three healthy controls hailing from similar geographical areas without a history of cancer enrolled as healthy controls. Excision repair cross-complementation group 1 polymorphisms (rs11615, rs3212986, rs735482, rs2336219, rs3212980, rs3212964, rs3212961 and rs2298881) were genotyped by appropriate methods. Distribution of genotypes and allele for ERCC1 polymorphisms (rs11615, rs3212986, rs735482, rs2336219, rs3212980, rs3212964, rs3212961 and rs2298881) were comparable among healthy controls and EOC patients. Interestingly, homozygous mutant and the minor allele for rs11615 and rs3212986 polymorphisms were significantly higher in nonresponder EOC patients when compared to those with a proper response to cisplatin treatment. The prevalence of other SNPs was comparable among the two treated clinical categories. Furthermore, combined genotype revealed significant association of rs11615: TT/ rs3212986: AA genotype combination with cisplatin nonresponder. Variants of rs11615, rs3212986 polymorphisms are associated with cisplatin resistance in Chinese EOC patients. Combined rs11615 and rs3212986 genotypes can be used as a predictive biomarker for platinum-based chemotherapy outcomes.

Excision repair cross-complementing group-1 (ERCC1) induction kinetics and polymorphism are markers of inferior outcome in patients with colorectal cancer treated with oxaliplatin

Background

ERCC1, a component of nucleotide excision repair pathway, is known to repair DNA breaks induced by platinum drugs. We sought to ascertain if ERCC1 expression dynamics and a single nucleotide polymorphism (SNP) rs11615 are biomarkers of sensitivity to oxaliplatin therapy in patients with colorectal cancer (CRC).

Methods

Western blot and qPCR for ERCC1 expression was performed from PBMCs isolated from patients receiving oxaliplatin-based therapy at specified timepoints. DNA was also isolated from 59 biorepository specimens for SNP analysis. Clinical benefit was determined using progression free survival (PFS) for metastatic CRC.

Results

ERCC1 was induced in PBMC in response to oxaliplatin in 13/25 patients with mCRC (52%). Median PFS with ERCC1 induction was 190d compared to 237d in non-induced patients (HR 2.35, CI 1.005-5.479; p=0.0182). ERCC1 rs11615 SNP analysis revealed that 43.3% harbored C/C, 41.2%-T/C and 15.5%-T/T genotype. Median PFS was significantly lower with C/C or T/C (211 and 196d) compared to T/T (590d; p=0.0310).

Conclusions

ERCC1 was induced in a sub-population of patients undergoing oxaliplatin treatment, which was associated with poorer outcome, suggesting this could serve as a marker of oxaliplatin response. C/C or C/T genotype in ERCC1 rs11615 locus decreased benefit from oxaliplatin.

Effects of gene polymorphisms on the risk of severe hyponatremia during DCF chemotherapy for patients with esophageal squamous cell carcinoma

Combination chemotherapy using docetaxel, cisplatin and 5-fluorouracil (DCF) is a promising treatment option for patients with advanced esophageal squamous cell carcinoma (ESCC), although its clinical application is limited by severe systemic toxicities. There are no validated markers for predicting the adverse effects caused by this regimen. This pharmacogenetic study enrolled 57 patients with chemotherapy-naive advanced ESCC between July 2012 and March 2016 (UMIN000008462). All patients received at least one course of DCF chemotherapy (docetaxel, 60 mg/m² on day 1; cisplatin, 70 mg/m² on day 1; 5-fluorouracil, 600 mg/m² on days 1-5). The associations between four gene polymorphisms (ERCC1 rs11615, GSTP1 rs1695, TYMS rs151264360 and XPD rs13181) and the development of grade 3/4 adverse events during the first course of chemotherapy were prospectively investigated. The patients had a median age of 66 years (range, 45-77 years) and the majority were male (51 males vs. 6 females). The treatment settings were neoadjuvant (47 patients), adjuvant (1 patient) and salvage (9 patients), with dose intensities of 100% (51 patients) or 80% (6 patients). The severe adverse events were leukopenia (70.2%), neutropenia (86.0%), febrile neutropenia (36.8%), acute kidney injury (29.1%) and hyponatremia (43.9%). Two polymorphisms were independently associated with the development of severe hyponatremia among patients carrying the minor allele (vs. patients with major homozygote genotype): TYMS 3'-UTR rs151264360 (odds ratio, 3.64; 95% confidence interval, 1.11-11.9) and XPD Lys751Gln rs13181 (odds ratio, 10.1; 95% confidence interval, 1.10-93.3). Therefore, the presence of the TYMS and XPD polymorphisms may aid in identifying patients with a high risk of developing severe hyponatremia during DCF chemotherapy.

ERCC1 rs11615 polymorphism increases susceptibility to breast cancer: a meta-analysis of 4547 individuals

Excision repair cross-complementation group 1 (ERCC1), a DNA repair protein, is vital for maintaining genomic fidelity and integrity. Despite the fact that a mounting body of case-control studies has concentrated on investigating the association of the ERCC1 rs11615 polymorphism and breast cancer risk, there is still no consensus on it. We conducted the current meta-analysis of all eligible articles to reach a much more explicit conclusion on this ambiguous association. A total of seven studies involving 2354 breast cancer cases and 2193 controls were elaborately selected for this analysis from the Embase, EBSCO, PubMed, WanFang, and China National Knowledge Infrastructure (CNKI) databases. Pooled odds ratios (ORs) and their 95% confidence intervals (CIs) were estimated in our meta-analysis. We found that the ERCC1 rs11615 polymorphism was significantly associated with breast cancer risk under all genetic models. When excluded, the studies that deviated from Hardy-Weinberg equilibrium (HWE), the pooled results of what remained significantly increase the risk of breast cancer under the allele model (OR = 1.14, 95% CI = 1.02-1.27, P=0.02), heterozygote model (OR = 1.24, 95% CI = 1.06-1.44, P=0.007), and dominant model (OR = 1.21, 95% CI = 1.05-1.41, P=0.01). This increased breast cancer risk was found in Asian population as well as under the heterozygote model (OR = 1.24, 95% CI = 1.05-1.48, P=0.013) and dominant model (OR = 1.20, 95% CI = 1.02-1.42, P=0.03). Our results suggest that the ERCC1 rs11615 polymorphism is associated with breast cancer susceptibility, and in particular, this increased risk of breast cancer existence in Asian population.

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.

Nucleotide excision repair pathway gene polymorphisms are linked to breast cancer risk in a Chinese population

Polymorphisms in nucleotide excision repair (NER) pathway genes are associated with the risk of breast cancer, but the relevance of these associations appeared to vary according to the ethnicity of the subjects. To systemically evaluate the potential associations between NER polymorphisms and breast cancer risk in a Chinese population, we carried out a case-control study on 450 breast cancer patients and 430 healthy controls. Sequenom MassARRAY was used for genotyping, and immunohistochemistry was performed to detect estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER-2) expression in tumor tissue. Our results showed that ERCC1 rs11615 (additive model: OR_adjusted: 1.36, 95% CI: 1.08-1.71, p = 0.009), XPC rs2228000 (additive model: OR_adjusted: 1.39, 95% CI: 1.13-1.72, p = 0.002) and ERCC2/XPD rs50872 (additive model: OR_adjusted: 1.32, 95% CI: 1.04-1.67, p = 0.021) were associated with an increased risk of breast cancer. Stratified analysis revealed three polymorphisms (rs11615, rs1800975, and rs50872) to be associated with breast cancer in menopausal females. Three polymorphisms were associated with specific breast cancer grades (rs11615 with grade 3, rs2228000 and rs50872 with grade 1-2). Two polymorphisms (rs2228001 and rs50872) were associated with the risk of breast cancer with negative lymph node involvement. rs1800975 and rs50872 were associated with the risk of ER⁻ and PR⁻ breast cancer, whereas rs11615 was associated with the risk of ER⁺ and PR⁺ breast cancer. We found that carriers of the T allele of ERCC1 rs11615, XPC rs2228000 and rs50872, particularly in postmenopausal females, have an increased risk of breast cancer.

Polymorphism in ERCC1 confers susceptibility of coronary artery disease and severity of coronary artery atherosclerosis in a Chinese Han population

Excision repair cross-complementing 1 (ERCC1) gene encodes ERCC1 protein, which is mainly responsible for the repair of DNA damage in different diseases including coronary artery atherosclerosis by acting as a rate-limiting element in nucleotide excision repair (NER). Using a three-stage case-control study with 3037 coronary artery disease (CAD) patients and 3002 controls, we investigated associations of three single nucleotide polymorphisms (SNPs) with CAD risk and severity of coronary artery atherosclerosis in Chinese Han population. In the discovery set, the variant allele T of rs11615 was significantly associated with higher CAD risk (adjusted OR = 1.27, P = 0.006) and severity of coronary artery atherosclerosis (adjusted OR = 1.54, P = 0.003). These associations were more remarkable in the merged set (adjusted OR = 1.23, P = 8 × 10^-6 for CAD risk; adjusted OR = 1.36, P = 4.3 × 10^-5 for severity of coronary artery atherosclerosis). And the expression level of ERCC1 was significantly higher in CAD cases than controls. Multiplicative interactions among SNP rs11615, alcohol drinking, history of T2DM, and history of hyperlipidemia could increase 5.06-fold risk of CAD (P = 1.59 × 10^-9). No significant association of rs2298881 and rs3212986 with CAD risk was identified. Taken together, SNP rs11615 in ERCC1 gene might confer susceptibility to CAD and severity of coronary atherosclerosis in a Chinese Han population.

Association between the ERCC1 polymorphism and platinum-based chemotherapy effectiveness in ovarian cancer: a meta-analysis

Background

Ovarian cancer is a prominent public health problem which affects people all around the world. Platinum-based chemotherapy is a common treatment for ovarian cancer, however, the effectiveness of chemotherapy varies from patient to patient. The excision repair cross complementation group 1 (ERCC1) protein may mediate chemotherapy resistance. A meta-analysis was conducted to explore whether platinum-based chemotherapy effectiveness could be attributed to the ERCC1 C19007T polymorphisms.

Methods

Seven major databases (EMBASE, Web of Science, Pubmed, Springer Link, Chinese National Knowledge Infrastructure (CNKI), EBSCO and Science Direct databases) were searched for eligible studies. Crude odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to evaluate the results.

Results

In this meta-analysis, 1169 subjects (425 non-responders and 744 responders) from 8 studies were included. The overall OR (C vs. T alleles) using random model was 1.07 (95% CI 0.75-1.52, P = 0.7), which was not statistically significant. Moreover, there was no significant difference in the analysis by race.

Conclusion

There is no association between the ERCC1 C19007T polymorphism and platinum-based chemotherapy effectiveness in ovarian cancer. The polymorphism did not have a significant impact on platinum-based chemotherapy in non-responders and responders.

Personalizing colon cancer therapeutics: targeting old and new mechanisms of action

The use of pharmaceuticals for colon cancer treatment has been increasingly personalized, in part due to the development of new molecular tools. In this review, we discuss the old and new colon cancer chemotherapeutics, and the parameters that have been shown to be predictive of efficacy and safety of these chemotherapeutics. In addition, we discuss how alternate pharmaceuticals have been developed in light of a potential lack of response or resistance to a particular chemotherapeutic.

Association between ERCC1 and XPA expression and polymorphisms and the response to cisplatin in testicular germ cell tumours

Background:

Cisplatin cures over 80% of testicular germ cell tumours (TGCTs), and nucleotide-excision repair (NER) modifies the sensitivity to cisplatin. We explored the association between NER proteins and their polymorphisms with cisplatin sensitivity (CPS) and overall survival (OS) of patients with non-seminomatous (ns)-TGCTs.

Methods:

The expression of ERCC1 and XPA and the presence of γH2AX were evaluated in cancer cell lines and in fresh ns-TGCTs. The ERCC1 protein was also determined in ns-TGCTs. The differences between CPS and non-CPS cell lines and patients were analysed by Student's t- or χ²-tests. The differences in OS were analysed using the log-rank test, and the hazard ratios (HRs) were calculated using the Cox model.

Results:

High ERCC1 expression was observed in the non-CPS cells, and both ERCC1 and γH2AX expressions were augmented after cisplatin treatment. Increased ERCC1 expression was also identified in non-CPS patients. Neither polymorphism was associated with either CPS or OS. The presence of ERCC1 was associated with non-CPS (P=0.05) and adjusted in the prognosis groups. The HR in ERCC1-negative and non-CPS patients was >14.43, and in ERCC1-positive and non-CPS patients the HR was >11.86 (P<0.001).

Conclusions:

High levels of ERCC1 were associated with non-CPS, suggesting that ERCC1 could be used as a potential indicator of the response to cisplatin and prognosis in ns-TGCTs.

MTHFR Glu429Ala and ERCC5 His46His polymorphisms are associated with prognosis in colorectal cancer patients: analysis of two independent cohorts from Newfoundland

Introduction

In this study, 27 genetic polymorphisms that were previously reported to be associated with clinical outcomes in colorectal cancer patients were investigated in relation to overall survival (OS) and disease free survival (DFS) in colorectal cancer patients from Newfoundland.

Methods

The discovery and validation cohorts comprised of 532 and 252 patients, respectively. Genotypes of 27 polymorphisms were first obtained in the discovery cohort and survival analyses were performed assuming the co-dominant genetic model. Polymorphisms associated with disease outcomes in the discovery cohort were then investigated in the validation cohort.

Results

When adjusted for sex, age, tumor stage and microsatellite instability (MSI) status, four polymorphisms were independent predictors of OS in the discovery cohort MTHFR Glu429Ala (HR: 1.72, 95%CI: 1.04–2.84, p = 0.036), ERCC5 His46His (HR: 1.78, 95%CI: 1.15–2.76, p = 0.01), SERPINE1 −675indelG (HR: 0.52, 95%CI: 0.32–0.84, p = 0.008), and the homozygous deletion of GSTM1 gene (HR: 1.4, 95%CI: 1.03–1.92, p = 0.033). In the validation cohort, the MTHFR Glu429Ala polymorphism was associated with shorter OS (HR: 1.71, 95%CI: 1.18–2.49, p = 0.005), although with a different genotype than the discovery cohort (CC genotype in the discovery cohort and AC genotype in the validation cohort). When stratified based on treatment with 5-Fluorouracil (5-FU)-based regimens, this polymorphism was associated with reduced OS only in patients not treated with 5-FU. In the DFS analysis, when adjusted for other variables, the TT genotype of the ERCC5 His46His polymorphism was associated with shorter DFS in both cohorts (discovery cohort: HR: 1.54, 95%CI: 1.04–2.29, p = 0.032 and replication cohort: HR: 1.81, 95%CI: 1.11–2.94, p = 0.018).

Conclusions

In this study, associations of the MTHFR Glu429Ala polymorphism with OS and the ERCC5 His46His polymorphism with DFS were identified in two colorectal cancer patient cohorts. Our results also suggest that the MTHFR Glu429Ala polymorphism may be an adverse prognostic marker in patients not treated with 5-FU.

Pharmacogenetics of conventional chemotherapy in non-small-cell lung cancer: a changing landscape?

Pharmacogenetics might be used to select patients who may benefit from specific chemotherapy that best matches the individual and tumor genetic profile, thus allowing maximum activity and minimal toxicity. Even if most studies in non-small-cell lung cancer yielded contradictory results, several potential biomarkers for sensitivity/resistance to platinum compounds, gemcitabine, taxanes and pemetrexed have been proposed. However, these markers need to be validated within larger prospective randomized trials of customized chemotherapy in homogeneous populations. Other critical points include the optimization/standardization of technical procedures, and further studies to unravel the extremely complex regulation of gene function. From this perspective, the evaluation of key factors influencing genotype-phenotype relationships, such as miRNAs, and functional studies to clarify pharmacokinetic/pharmacodynamic interactions, are fundamental for the pharmacogenetic optimization of cancer chemotherapy. Finally, limitation of the traditional pharmacogenetic approach relying only on candidate genes suspected of affecting drug response is now being overcome by the use of novel genome-wide studies.

Nucleotide excision repair and anti-cancer chemotherapy

DNA repair is an important effector of anti-cancer drug resistance. In recent years, it has become apparent that DNA repair is an extremely complex process. Processes within DNA repair that may contribute to one or more drug resistance phenotypes include; O-6-alkyltransferase activity, base excision repair, mismatch repair, nucleotide excision repair, and gene specific repair. Clearly, several of these processes may show increased activity within any single cell, or tumor, at any one time. This review attempts to touch briefly upon the question of the distinctions between each of these specific pathways; and then seeks to expand on nucleotide excision repair as a possible effector of cellular and clinical resistance to platinum-based anticancer therapy.

ERCC1 intron 1 was associated with breast cancer risk

INTRODUCTION

There are numerous studies addressing associations of polymorphisms in DNA repair genes and cancer risks because accurate and efficient DNA repair is crucial to genomic integrity and fidelity. ERCC1 is important in DNA nucleotide excision repair.

MATERIAL AND METHODS

We genotyped constitutive variants of ERCC1 in approximately 300 adults with breast adenocarcinoma and 126 controls of Iranian women. In total, 426 Iranian sporadic breast cancer affected women compared to the control group were studied by PCR-RFLP for ERCC1 variant.

RESULTS

The genotype ERCC1 TT has the highest frequency in both groups (36.6 in patients and 8.5 in controls). The genotype ERCC1 was the most important risk factor in our population [GG/AA odds ratio: 0.692, 95% confidence interval (CI): 0.4-1.199, p = 0.188; GG/AG odds ratio: 3.333, 95% CI: 1.917-5.795, p = 0.001; AA/AG odds ratio: 0.208, 95% CI: 0.124-0.348, p = 0.342].

CONCLUSIONS

Our patients was associated with breast cancer risk.

Polymorphisms of ERCC1 genotype associated with response to imatinib therapy in chronic phase chronic myeloid leukemia

DNA repair machinery may contribute to the mechanism of the action in imatinib. We examined the association between the single nucleotide polymorphism (SNP) markers involved in the DNA repair enzyme pathway (ERCC1/2/4/5, XRCC1/2/4/5) and the clinical outcomes following an imatinib therapy in chronic phase chronic myeloid leukemia (CML) patients. A total of 169 Korean patients were included. Of the 19 SNPs from these patients, those with the TT genotype of ERCC1 (rs11615) showed a higher probability of achieving major cytogenetic response [P = 0.002, HR 5.14 (95 % CI 1.83-14.43)], complete cytogenetic response [P = 0.012, HR 3.47 (95 % CI 1.31-9.17)], and major molecular response [P = 0.001, HR 5.71 (95 % CI 2.13-15.30)] than those with CC or CT genotypes. This suggests that SNP markers on ERCC1 may predict the response to imatinib therapy, which proposes the potential involvement of the DNA repair machinery in the mechanism of imatinib action in chronic phase CML.

Comparison of ERCC1/XPF genetic variation, mRNA and protein levels in women with advanced stage ovarian cancer treated with intraperitoneal platinum

OBJECTIVE

Approximately 20% of patients receiving platinum-based chemotherapy for epithelial ovarian cancer (EOC) are refractory or develop early recurrence. Identifying these patients early could reduce treatment-associated morbidity and allow quicker transfer to more effective therapies. Much attention has focused on ERCC1 as a potential predictor of response to therapy because of its essential role in the repair of platinum-induced DNA damage. The purpose of this study was to accurately measure protein levels of ERCC1 and its essential binding partner XPF from patients with EOC treated with platinum-based therapy and determine if protein levels correlate with mRNA levels, patient genotypes or clinical outcomes.

METHODS

ERCC1 and XPF mRNA and protein levels were measured in frozen EOC specimens from 41 patients receiving intraperitoneal platinum-based chemotherapy using reverse transcription polymerase chain reaction and western blots. Genotypes of common nucleotide polymorphisms were also analyzed. Patient outcomes included progression free (PFS) and overall survival (OS).

RESULTS

Expression of ERCC1 and XPF were tightly correlated with one another at both the mRNA and protein level. However, the mRNA and protein levels of ERCC1 were not positively correlated. Likewise, none of the SNPs analyzed correlated with ERCC1 or XPF protein levels. There was an inverse correlation between mRNA levels and patient outcomes.

CONCLUSION

Neither genotype nor mRNA levels are predictive of protein expression. Despite this, low ERCC1 mRNA significantly correlated with improved PFS and OS.

Association between polymorphisms of ERCC1 and survival in epithelial ovarian cancer patients with chemotherapy

Aim: We evaluated whether the ERCC1 polymorphisms had an effect on survival in epithelial ovarian cancer (EOC) patients with platinum-based chemotherapy. Materials & methods: Clinical data of 209 EOC patients between 2002 and 2008 were reviewed. The genotypes of 19007T/C and 8092C/A polymorphisms were assessed in all patients using PCR–RFLP. Results: The 19007T/C polymorphism was significantly associated with response to treatment. Compared with the patients carrying C/C genotype, the patients with the T/T genotype have a significantly decreased response to platinum-based chemotherapy (odds ratio: 32.26; 95% CI: 3.66–250.00). Cox’s multivariate analysis suggested that EOC patients with the T/T genotype had an increased risk of disease progression (hazard ratio: 3.34; 95% CI: 1.77–6.29) and death (hazard ratio: 2.87; 95% CI: 1.38–5.96) compared with those carrying the C/C genotype. Conclusion: The 19007T/C polymorphism may be a useful prognostic marker in patients with EOC treated with platinum-based chemotherapy in Chinese women.

Original submitted 26 October 2011; Revision submitted 5 December 2011

Pre-treatment tumor expression of ERCC1 in women with advanced stage epithelial ovarian cancer is not predictive of clinical outcomes: a Gynecologic Oncology Group study

OBJECTIVE

Excision repair cross-complementation group 1 (ERCC1) is required for the repair of platinum-induced DNA damage. This study sought to assess the prognostic value of ERCC1 expression, measured by immunohistochemistry (IHC) using a highly specific antibody, in advanced epithelial ovarian cancer (EOC) patients treated with platinum-based chemotherapy.

METHODS

Formalin-fixed, paraffin-embedded tumors were collected from two GOG phase III trials (GOG-172 and GOG-182) of patients with stage III/IV EOC treated with platinum-based chemotherapy. ERCC1 was detected by (IHC) using FL297 polyclonal antibody and tumors were categorized as negative or positive, based on nuclear staining of tumor cells. ERCC1 genotyping was performed as previously reported. Associations between ERCC1 expression and clinical characteristics, platinum responsiveness, progression-free survival (PFS) or overall survival (OS) were evaluated.

RESULTS

Of 408 eligible patients, 27% had tumors that were ERCC1 positive. ERCC1 expression was not associated with clinical characteristics or platinum-responsiveness. Women with ERCC1-positive versus -negative tumors had similar median PFS (17.9 months versus 17.5 months, respectively, p=0.59), median OS (52.0 months versus 47.0 months, respectively, p=0.30), risk of disease progression (adjusted hazard ratio [HR]=0.90, 95% confidence interval (CI): 0.71-1.15, p=0.41), and risk of death (adjusted HR=0.81, 95% CI: 0.61-1.07, p=0.14). ERCC1 expression, as measured by IHC, was not associated with single nucleotide polymorphisms (SNPs), in codon 118 and C8092A, of the ERCC1 gene.

CONCLUSIONS

ERCC1 expression, measured by IHC in pre-treatment tumor specimens, using a highly specific antibody, has limited clinical value in patients with advanced EOC treated with platinum and taxane based chemotherapy.

Pre-treatment tumor expression of ERCC1 in women with advanced stage epithelial ovarian cancer is not predictive of clinical outcomes: a Gynecologic Oncology Group study

OBJECTIVE

Excision repair cross-complementation group 1 (ERCC1) is required for the repair of platinum-induced DNA damage. This study sought to assess the prognostic value of ERCC1 expression, measured by immunohistochemistry (IHC) using a highly specific antibody, in advanced epithelial ovarian cancer (EOC) patients treated with platinum-based chemotherapy.

METHODS

Formalin-fixed, paraffin-embedded tumors were collected from two GOG phase III trials (GOG-172 and GOG-182) of patients with stage III/IV EOC treated with platinum-based chemotherapy. ERCC1 was detected by (IHC) using FL297 polyclonal antibody and tumors were categorized as negative or positive, based on nuclear staining of tumor cells. ERCC1 genotyping was performed as previously reported. Associations between ERCC1 expression and clinical characteristics, platinum responsiveness, progression-free survival (PFS) or overall survival (OS) were evaluated.

RESULTS

Of 408 eligible patients, 27% had tumors that were ERCC1 positive. ERCC1 expression was not associated with clinical characteristics or platinum-responsiveness. Women with ERCC1-positive versus -negative tumors had similar median PFS (17.9 months versus 17.5 months, respectively, p=0.59), median OS (52.0 months versus 47.0 months, respectively, p=0.30), risk of disease progression (adjusted hazard ratio [HR]=0.90, 95% confidence interval (CI): 0.71-1.15, p=0.41), and risk of death (adjusted HR=0.81, 95% CI: 0.61-1.07, p=0.14). ERCC1 expression, as measured by IHC, was not associated with single nucleotide polymorphisms (SNPs), in codon 118 and C8092A, of the ERCC1 gene.

CONCLUSIONS

ERCC1 expression, measured by IHC in pre-treatment tumor specimens, using a highly specific antibody, has limited clinical value in patients with advanced EOC treated with platinum and taxane based chemotherapy.

Role of DNA repair gene polymorphisms in the efficiency of platinum-based adjuvant chemotherapy for non-small cell lung cancer

BACKGROUND

Cisplatin-based adjuvant treatment of non-small cell lung cancer (NSCLC) has become standard, thanks to the studies that have shown a significant survival advantage. The identification of patients who could benefit from this adjuvant treatment would allow ineffective and toxic administrations to be avoided. Immunohistochemical expression of the excision repair cross-complementation group (ERCC)-1 protein has been associated with response to platinum-based chemotherapy in patients with NSCLC, and some polymorphisms of the genes involved in DNA repair have been shown to be associated with survival in advanced NSCLC.

OBJECTIVE

The aim of our study was to evaluate the progression-free survival and tolerability of adjuvant treatment with platinum-based chemotherapy in patients with NSCLC, according to common DNA repair gene polymorphisms and ERCC1 expression.

METHODS

We investigated the association of three DNA repair gene polymorphisms - Asn118Asn in ERCC1 (rs11615), Lys751Gln in ERCC2 (rs13181), and Asp1104His in ERCC5 (rs17655) - with the progression-free survival of 85 patients treated with platinum-based chemotherapy after surgery for NSCLC.

RESULTS

We did not find significant associations between any of these polymorphisms and progression-free survival, nor did we observe any difference in progression-free survival according to ERCC1 expression.

CONCLUSION

The previously reported impact of DNA repair gene polymorphisms on platinum-based chemotherapy treatment of advanced NSCLC was not observed in our study in the adjuvant setting.

Single nucleotide polymorphisms in DNA repair genes and risk of cervical cancer: A case-control study

In this report, we describe a case control study in a Chinese population aimed at identifying possible associations between susceptibility to cervical cancer and single nucleotide polymorphisms in XRCC1 194C>T, XRCC1 280G>A, XRCC1 399G>A, ERCC2 751A>C, ERCC2 156C>A, ERCC1 118C>T, PARP1 762T>C, RAD51 135G>C and HER2 655A>G. The cases comprised 154 patients: 80 cervical squamous cell carcinomas (SCCs), 2 adenocarcinomas and 72 cervical intraepithelial neoplasias (CINs). A total of 177 healthy women were recruited as the controls. A significant association was found between ERCC1 118C>T and SCC in the additive genetic model [odds ratio (OR)=1.711; 95% confidence interval (CI), 1.089-2.880; p=0.021] and the dominant genetic model (OR=1.947; 95% CI, 1.056-3.590; p=0.033). Among women with a smoking family member, ERCC1 118C>T increased SCC risk in the additive model (OR=2.800; 95% CI, 1.314-5.968; p=0.008). For women who had first intercourse before 22 years of age, XRCC1 280G>A was found to act as a protective factor for SCC under the additive model (OR=0.228; 95% CI, 0.058-0.900; p=0.035), while RAD51 135G>C was a risk factor for CIN (OR=4.246; 95% CI, 1.335-13.502; p=0.014). For women who had first intercourse after 22 years of age, the additive genetic model showed RAD51 135G>C (OR=0.359; 95% CI, 0.138-0.934; p=0.036) and HER2 655A>G (OR=0.309; 95% CI, 0.098-0.972; p=0.045) to be protective factors for SCC. XRCC1 399G>A increased CIN risk among women who first gave birth before the age of 22 in the additive genetic model (OR=4.459; 95% CI, 1.139-17.453; p=0.032). For those who first gave birth after age 22, ERCC1 118C>T was found to be a risk factor for SCC in the additive genetic model (OR=1.884; 95% CI, 1.088-3.264; p=0.024). A significant interaction was observed between RAD51 135G>C and age at first intercourse (p(interaction)=0.033 for SCC, p(interaction)=0.021 for CIN), as well with sexual partner number (p(interaction)=0.001 for SCC). The interaction between HER2 655A>G and age at first intercourse, ERCC2 156C>A and family smoking status and XRCC1 280G>A and alcohol consumption were significant, with p(interaction)=0.023 for SCC, p(interaction)=0.021 for CIN and p(interaction)=0.025 for SCC, respectively.

Pharmacogenetic analyses of cisplatin-induced nephrotoxicity indicate a renoprotective effect of ERCC1 polymorphisms

AIM

We investigated whether genetic polymorphisms may contribute to the interpatient variability of cisplatin-induced nephrotoxicity.

PATIENTS & METHODS

Polymorphisms in the candidate genes GSTM1, GSTT1, OCT1, OCT2, LARP2, ERCC1, XRCC1 and EPO were analyzed for associations with nephrotoxicity in 79 cancer patients receiving cisplatin-containing chemotherapy.

RESULTS

Higher cisplatin dose was associated with strongly decreased estimated glomerular filtration rates (eGFR) (r(2) = 0.205). Two highly genetically linked polymorphisms in the ERCC1 gene, 8092C>A and Asn118Asn, were significantly associated with change in eGFR, accounting for an additional 13% of interindividual variability. Homozygous carriers of the 8092A allele in ERCC1 showed no reduction in eGFR, compared with the 11.5% mean eGFR decrease in C allele carriers (p = 0.004). Homozygous carriers of the C allele of Asn118Asn showed no reduction in eGFR, compared with the 12.8% mean eGFR decrease seen in T allele carriers (p = 0.047). Polymorphisms in the other candidate genes were not associated with cisplatin-induced nephrotoxicity.

CONCLUSION

Genetic polymorphisms in ERCC1 may be valuable predictors of cisplatin-induced nephrotoxicity.

ERCC1 and XRCC1 as biomarkers for lung and head and neck cancer

Advanced stage non-small cell lung cancer and head and neck squamous cell carcinoma are both treated with DNA damaging agents including platinum-based compounds and radiation therapy. However, at least one quarter of all tumors are resistant or refractory to these genotoxic agents. Yet the agents are extremely toxic, leading to undesirable side effects with potentially no benefit. Alternative therapies exist, but currently there are no tools to predict whether the first-line genotoxic agents will work in any given patient. To maximize therapeutic success and limit unnecessary toxicity, emerging clinical trials aim to inform personalized treatments tailored to the biology of individual tumors. Worldwide, significant resources have been invested in identifying biomarkers for guiding the treatment of lung and head and neck cancer. DNA repair proteins of the nucleotide excision repair pathway (ERCC1) and of the base excision repair pathway (XRCC1), which are instrumental in clearing DNA damage caused by platinum drugs and radiation, have been extensively studied as potential biomarkers of clinical outcomes in lung and head and neck cancers. The results are complex and contradictory. Here we summarize the current status of single nucleotide polymorphisms, mRNA, and protein expression of ERCC1 and XRCC1 in relation to cancer risk and patient outcomes.

Part 4: pharmacogenetic variability in anticancer pharmacodynamic drug effects

Response to treatment with anticancer drugs is subject to wide interindividual variability. This variability is expressed not only as differences in severity and type of toxicity, but also as differences in effectiveness. Variability in the constitution of genes involved in the pharmacokinetic and pharmacodynamic pathways of anticancer drugs has been shown to possibly translate into differences in treatment outcome. The overall knowledge in the field of pharmacogenetics has tremendously increased over the last couple of years, and has thereby provided opportunities for patient-tailored anticancer therapy. In previous parts of this series, we described pharmacogenetic variability in anticancer phase I and phase II drug metabolism and drug transport. This fourth part of a four-part series of reviews is focused on pharmacodynamic variability and encompasses genetic variation in drug target genes such as those encoding thymidylate synthase, methylene tetrahydrofolate reductase, and ribonucleotide reductase. Furthermore, genetic variability in other pharmacodynamic candidate genes involved in response to anticancer drugs is discussed, including genes involved in DNA repair such as those encoding excision repair crosscomplementing group 1 and group 2, x-ray crosscomplementing group 1 and group 3, and breast cancer genes 1 and 2. Finally, somatic mutations in KRAS and the gene encoding epidermal growth factor receptor (EGFR) and implications for EGFR-targeted drugs are discussed. Potential implications and opportunities for patient and drug selection for genotype-driven anticancer therapy are outlined.

Part 1: background, methodology, and clinical adoption of pharmacogenetics

Equivalent drug doses may lead to wide interpatient variability with regard to drug response, reflected by differences in drug activity and normal tissue toxicity. A major factor responsible for this variability is variation among patients in their genetic constitution. Genetic polymorphism may affect the activity of proteins encoded, which in turn may lead to changes in the pharmacokinetic and pharmacodynamic behavior of a drug, observed as differences in drug transport, drug metabolism, and pharmacodynamic drug effects. Recent insights into the functional effect of polymorphism in genes that are involved in the pharmacokinetics and pharmacodynamics of anticancer drugs have provided opportunities for patient-tailored therapy in oncology. Individualized pharmacotherapy based on genotype will help to increase treatment efficacy while reducing unnecessary toxicity, especially of drugs characterized by a narrow therapeutic window, such as anticancer drugs. We provide a series of four reviews aimed at implementing pharmacogenetic-based drug and dose prescription in the daily clinical setting for the practicing oncologist. This first part in the series describes the functional impact of genetic polymorphism and provides a general background to and insight into possible clinical consequences of pharmacogenetic variability. It also discusses different methodologies for clinical pharmacogenetic studies and provides a concise overview about the different laboratory technologies for genetic mutation analysis that are currently widely applied. Subsequently, pharmacogenetic association studies in anticancer drug transport, phase I and II drug metabolism, and pharmacodynamic drug effects are discussed in the rest of the series. Opportunities for patient-tailored pharmacotherapy are highlighted.

Expression of ERCC1 and its clinicopathological correlations in non-small cell lung cancer

Excision Repair Cross-Complementing Group 1 (ERCC1) is an important DNA repair gene, playing critical role in nucleotide excision repair pathway and having a significant influence on genomic instability. Some studies support that ERCC1 might be a potential predictive and prognostic marker in non-small cell lung cancer (NSCLC). ERCC1 has also been shown to be a promising biomarker in NSCLC treated with a cisplatin-based regimen. Therefore, the determination of ERCC1 expression at DNA, mRNA and protein level in different stages of NSCLC is still an important topic in the cancer. Ninety-one formalin-fixed paraffin-embedded tumor samples histopathologically diagnosed as NSCLC were examined in this study. ERCC1 expression at protein level were scored by immunohistochemistry. The gene amplification and mRNA expression levels for ERCC1 were determined by real-time quantitative PCR. There was complete concordance among the three methods in 39 tumor samples (42.9%). A strong correlation was found between DNA amplification and mRNA expression (r=0.662) while there was no correlation between mRNA and protein assessment for ERCC1 expression (r=-0.013). ERCC1 expression at mRNA and DNA level (63.1 and 84.2%, respectively) in tumors at stage III was higher than at the other stages. In contrast, the protein expression at stage II and III (56.6 and 52.6%, respectively) of NSCLC was lower than that of tumors with stage I NSCLC. These results show that the mechanism by which ERCC1 expression might play a role in tumor behavior. This study was also confirmed that the appropriate validation and qualification in methods used for ERCC1 status were needed before its clinical application and implementation.

The ERCC1 N118N polymorphism does not change cellular ERCC1 protein expression or platinum sensitivity

Genetic polymorphisms in ERCC1 are thought to contribute to altered sensitivity to platinum-based chemotherapy. Although ERCC1 N118N (500 C>T, rs11615) is the most studied polymorphism, the impact of this polymorphism on platinum-based chemotherapy remains unclear. This is the first study in which the functional impact of ERCC1 N118N on gene expression and platinum sensitivity was explored. The aim of this study is to investigate if the reduced codon usage frequency of AAT, which contains the variant allele of the silent mutation, has functional impact on ERCC1 in a well-controlled biological system. Specifically, the ERCC1 cDNA clone with either the C or T allele was introduced into an ERCC1 deficient cell line, UV20, and assayed for the effect of the two alleles on ERCC1 transcription, translation and platinum sensitivity. Both ERCC1 mRNA and protein expression levels increased upon cisplatin treatment, peaking at 4h post-treatment, however there were no differences between the two alleles (p>0.05). Cells complemented with ERCC1 showed significantly higher survival proportion than the parental cell line following platinum exposure (p<0.0001), although no differences were observed between the cells transfected with the wild type or the polymorphic allele. These data suggest that N118N itself is not related to the phenotypic differences in ERCC1 expression or function, but rather this polymorphism may be linked to other causative variants or haplotypes.

Predictive value of ERCC1 and XPD polymorphism in patients with advanced non-small cell lung cancer receiving platinum-based chemotherapy: a systematic review and meta-analysis

The published data on the predictive value of polymorphism of ERCC1 and XPD in patients with advanced non-small cell lung cancer receiving platinum-based chemotherapy are inconclusive. To derive a more precise estimation of the relationship, a meta-analysis was performed. Relevant studies were identified by searching the Medline, Embase, CNKI and American Society of Clinical Oncology abstract databases. Inclusion criteria were patients with advanced NSCLC, received platinum-based chemotherapy, evaluation of polymorphism of ERCC1 and XPD and overall response rate (ORR). A total of 12 studies were included in this meta-analysis. For studies evaluating ERCC1 polymorphism at codon 118, the ORR for the wild-type C/C genotype versus the heterozygous C/T and T/T genotype was 2.17 (95% confidence interval (CI), 1.43-3.33; P = 0.000). For studies evaluating XPD Asp312Asn and XPD Lys751Gln, the pooled OR was 1.33 (95% CI, 0.92-1.91; P = 0.13) and 1.02 (95% CI, 0.72-1.45; P = 0.915), respectively. The results indicated that platinum-based chemotherapy sensitivity was significantly associated with polymorphism of ERCC1 C118T. However, XPD Asp312Asn and XPD Lys751Gln were not predictive makers for platinum-based chemotherapy in patients with advanced NSCLC.

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.

Pharmaco(epi)genomics in ovarian cancer

Ovarian cancer shows considerable variability in its chemoresponse, however, the prospect of individualized medicine holds high hopes for improving patient survival. The influence of interindividual genomic polymorphisms on drug response (pharmacogenomics) is well established, and a variety of candidate loci in ovarian tumors have been identified, including ERCC1, ABCB1 and p53 variants. Recently pharmacoepigenomic modulators of key genes and pathways, such as promoter methylation (MLH1 and BRCA1 genes) and microRNA regulation (PTEN/AKT and NF-κB pathways) have been implicated in ovarian cancer chemoresponse. Epigenomic studies have until now mainly focused on tumor-specific changes, although germ-line epigenetic change may also be of importance. However, assessing the relevance of these potential pharmaco(epi)genomic biomarkers in clinical trials requires well powered studies in homogeneous populations, with independent validation sets, to distinguish real associations from false-positives. In addition, the selection of one gene or locus as having sufficient phenotypic effect to impact on clinical outcome may be an oversimplification. Integrated approaches that identify stable pharmacogenomic and epigenomic patterns and their relationship with expression patterns and gene function will be increasingly necessary.

ERCC1 polymorphism, expression and clinical outcome of oxaliplatin-based adjuvant chemotherapy in gastric cancer

AIM: To determine the influence of excision repair cross complementing group 1 (ERCC1) codon 118 polymorphism and mRNA level on the clinical outcome of gastric cancer patients treated with oxaliplatin-based adjuvant chemotherapy.

METHODS: Eighty-nine gastric cancer patients treated with oxalipatin-based adjuvant chemotherapy were included in this study. ERCC1 codon 118 C/T polymorphism was tested by polymerase chain reaction-ligation detection reaction (PCR-LDR) method in peripheral blood lymphocytes of those patients; and the intratumoral ERCC1 mRNA expression was measured using reverse transcription PCR in 62 patients whose tumor tissue specimens were available.

RESULTS: No significant relationship was found between ERCC1 codon 118 polymorphism and ERCC1 mRNA level. The median relapse-free and overall survival period was 20.1 mo and 28.4 mo, respectively. The relapse-free and overall survivals in patients with low levels of ERCC1 mRNA were significantly longer than those in patients with high levels (P < 0.05), while there was no significant association found between ERCC1 118 genotypes and the disease prognosis. Multivariate analysis also showed that ERCC1 mRNA level was a potential predictor for relapse and survival in gastric cancer patients treated with oxaliplatin-based adjuvant chemotherapy (P < 0.05).

CONCLUSION: ERCC1 codon 118 polymorphism has no significant impact on ERCC1 mRNA expression, and the intratumoral ERCC1 mRNA level but not codon 118 polymorphism may be a useful predictive parameter for the relapse and survival of gastric cancer patients receiving oxaliplatin-based adjuvant chemotherapy.

Association between nucleotide excision repair gene polymorphisms and chromosomal damage in coke-oven workers

The associations between several genetic polymorphisms of nucleotide excision repair genes (NER) and chromosome damage level were studied among 140 coke-oven workers exposed to a high level of polyaromatic hydrocarbons (PAHs) and 66 non-exposed workers. Seven polymorphisms with functional potential in five NER genes (ERCC1, ERCC2, ERCC4, ERCC5 and ERCC6) were genotyped in the 206 study subjects. Multivariate analysis of covariance revealed that coke-oven workers with the ERCC1 19007 CC genotype had significantly higher cytokinesis-block micronucleus frequency (CBMN) (10.5 +/- 6.8 per thousand) than those with CT (8.1 +/- 6.6 per thousand, p = 0.01) or TT (6.6 +/- 3.7-/ per thousand p = 0.05) or CT+TT genotypes (7.5 +/- 6.3 per thousand, p = 0.004). The ERCC6 A3368G polymorphism was also associated with CBMN frequency among coke-oven workers. Subjects with the AA genotype have a significantly higher CBMN frequency (10.0 +/- 6.9 per thousand) than those with AG (6.7 +/- 4.2 per thousand, p = 0.05) or AG+GG genotypes (6.6 +/- 4.1 per thousand, p = 0.02). Stratification analysis revealed the significant associations between ERCC1 C19007T and ERCC6 A3368G, and the CBMN frequencies were only found among older workers. In addition, a significant association between ERCC2 G23591A polymorphism and CBMN frequencies was also found among older coke-oven workers. The results suggest that polymorphisms of ERCC1 C19007T, ERCC6 A3368G and ERCC2 G23591A are associated with the CBMN frequencies among coke-oven workers.

Pharmacogenetic prediction of clinical outcome in advanced colorectal cancer patients receiving oxaliplatin/5-fluorouracil as first-line chemotherapy

To determine whether molecular parameters could be partly responsible for resistance or sensitivity to oxaliplatin (OX)-based chemotherapy used as first-line treatment in advanced colorectal cancer (CRC). We studied the usefulness of the excision repair cross-complementing 1 (ERCC1), xeroderma pigmentosum group D (XPD), XRCC1 and GSTP1 polymorphisms as predictors of clinical outcome in these patients. We treated 126 CRC patients with a first-line OX/5-fluorouracil chemotherapeutic regimen. Genetic polymorphisms were determined by real-time PCR on an ABI PRISM 7000, using DNA from peripheral blood. Clinical response (CR), progression-free survival (PFS) and overall survival (OS) were evaluated according to each genotype. In the univariate analysis for CR, ERCC1-118 and XPD 751 polymorphisms were significant (P=0.02 and P=0.05, respectively). After adjustment for the most relevant clinical variables, only ERCC1-118 retained significance (P=0.008). In the univariate analysis for PFS, ERCC1-118 and XPD 751 were significant (P=0.003 and P=0.009, respectively). In the multivariant analysis, only the XPD 751 was significant for PFS (P=0.02). Finally, ERCC1-118 and XPD 751 polymorphisms were significant in the univariate analysis for OS (P=0.006 and P=0.015, respectively). Both genetic variables remained significant in the multivariate Cox survival analysis (P=0.022 and P=0.03). Our data support the hypothesis that enhanced DNA repair diminishes the benefit of platinum-based treatments.

ERCC1 expression as a predictive marker of squamous cell carcinoma of the head and neck treated with cisplatin-based concurrent chemoradiation

The excision repair cross-complementation group 1 (ERCC1) enzyme plays a rate-limiting role in the nucleotide excision repair pathway and is associated with resistance to platinum-based chemotherapy. The purpose of this study was to evaluate the role of ERCC1 expression as a predictive marker of survival in patients with locally advanced squamous cell carcinoma of the head and neck (SCCHN) treated with cisplatin-based concurrent chemoradiotherapy (CCRT). ERCC1 expression was assessed by immunohistochemical staining. The median age of the 45 patients analysed was 56 years (range 27-75 years), and 82% were men; 73% of all specimens showed high expression of ERCC1. The overall tumour response rate after CCRT was 89%. The median follow-up was 53.6 months (95% CI, 34.5-72.7 months). The 3-year progression-free survival (PFS) and overall survival (OS) rates were 58.7 and 61.3%, respectively. Univariate analyses showed that patients with low expression of ERCC1 had a significantly higher 3-year PFS (83.3 vs 49.4%, P=0.036) and OS (91.7 vs 45.5%, P=0.013) rates. Multivariate analysis showed that low expression of ERCC1 was an independent predictor for prolonged survival (HR, 0.120; 95% CI, 0.016-0.934, P=0.043). These results suggest that ERCC1 expression might be a useful predictive marker of locally advanced SCCHN in patients treated with cisplatin-based CCRT.

The potential role of pharmacogenomic and genomic in the adjuvant treatment of early stage non small cell lung cancer

Although notable progress has been made in the treatment of non-small-cell lung cancer (NSCLC) in recent years, this disease is still associated with a poor prognosis. Despite early-stage NSCLC is considered a potentially curable disease following complete resection, the majority of patients relapse and eventually die after surgery. Adjuvant chemotherapy prolongs survival, altough the absolute improvement in 5-year overall survival is only approximately 5%.Trying to understand the role of genes which could affect drug activity and response to treatment is a major challenge for establishing an individualised chemotherapy according to the specific genetic profile of each patient. Among genes involved in the DNA repair system, the excision repair cross-complementing 1 (ERCC1) is a useful markers of clinical resistance to platinum-based chemotherapy. In the International Lung Cancer Trial (IALT) adjuvant chemotherapy significantly prolonged survival among patients with ERCC1 negative tumors but not among ERCC1-positive patients. BRCA1 and ribonucleotide reductase M1 (RRM1), two other key enzymes in DNA synthesis and repair, appear to be modulators of drug sensitivity and may provide additional information for customizing adjuvant chemotherapy.Several clinical trials suggest that overexpression of class III beta-tubulin is an adverse prognostic factor in cancer since it could be responsible for resistance to anti-tubulin agents. A retrospective analysis of NCIC JBR.10 trial showed that high tubulin III expression is associated with a higher risk of relapse following surgery alone but also with a higher probability of benefit from adjuvant cisplatin plus vinorelbine chemotherapy.Finally, the use of gene expression patterns such as the lung metagene model could provide a potential mechanism to refine the estimation of a patient's risk of disease recurrence and could affect treatment decision in the management of early stage of NSCLC.In this review we will discuss the potential role of pharmacogenomic approaches to guide the medical treatment of early stage NSCLC.

Ethnic disparities in Americans of European descent versus Americans of African descent related to polymorphic ERCC1, ERCC2, XRCC1, and PARP1

Nucleotide excision repair (NER) and base excision repair (BER) pathways are DNA repair pathways that are important in carcinogenesis and in response to DNA-damaging chemotherapy. ERCC1 and ERCC2 are important molecular markers for NER; XRCC1 and PARP1 are important molecular markers for BER. Functional polymorphisms have been described that are associated with altered expression levels of these genes and with altered DNA repair capability. We assayed genomic DNA from 156 Americans of European descent and 164 Americans of African descent for the allelic frequencies of specific polymorphisms of ERCC1 N118N (500C>T), ERCC1 C8092A, ERCC2 K751Q (2282A>C), XRCC1 R399Q (1301G>A), XRCC1 R194W (685C>T), and PARP1 V762A (2446T>C). Differences were observed between Americans of European descent and Americans of African descent in the allelic frequencies of the ERCC1 N118N polymorphism (P < 0.000001). Differences were also observed between these two ethnic groups for ERCC2 K751Q (P = < 0.006675), XRCC1 R399Q (P < 0.000001), and PARP1 V762A (P = 0.000001). The ERCC1 N118N polymorphic variant that is seen most commonly in Americans of European descent is associated with a measurable reduction in NER function. ERCC1-mediated reduction in NER functionality affects the repair of cisplatin-DNA lesions.

ERCC1 Genotype and Phenotype in Epithelial Ovarian Cancer Identify Patients Likely to Benefit From Paclitaxel Treatment in Addition to Platinum-Based Therapy

Purpose

To investigate the effect of excision repair cross-complementation group 1 (ERCC1) on treatment response and survival of patients treated with platinum chemotherapy with or without paclitaxel.

Patients and Methods

Tumor samples from epithelial ovarian cancer patients were evaluated for ERCC1 mRNA expression and a single nucleotide polymorphism at codon 118 (C>T). Of 178 patients treated with postoperative platinum-based chemotherapy, 75 were also given paclitaxel. For all of these patients, ERCC1 expression and genotype were analyzed for associations with treatment response and survival.

Results

Among the 103 patients treated with platinum without paclitaxel, the C/C genotype, compared with C/T and T/T, was associated with greater risk of disease progression and death (hazard ratio [HR], 1.95, P = .051; HR, 2.01, P = .033, respectively); high levels of ERCC1 mRNA, compared with low levels, were associated with greater risk of disease progression (HR, 2.41; P = .014). Similarly, when the ERCC1 data were combined, patients with the C/C genotype and high ERCC1 expression had greater risk for disease progression (HR, 3.73; P = .003) compared with those with low expression and non-C/C genotype. However, for the 75 patients treated with platinum plus paclitaxel, the C/C genotype and high ERCC1 expression were not associated with poor prognosis, suggesting that paclitaxel may help to alleviate ERCC1-related platinum resistance.

Conclusion

Ovarian cancer patients with high ERCC1 expression or the C/C genotype at codon 118 may benefit from the combination of platinum and paclitaxel, while those with low ERCC1 expression or the C/T or T/T genotype may respond well to platinum without paclitaxel.

Genetic polymorphisms in the nucleotide excision repair pathway and lung cancer risk: a meta-analysis

Various DNA alterations can be caused by exposure to environmental and endogenous carcinogens. Most of these alterations, if not repaired, can result in genetic instability, mutagenesis and cell death. DNA repair mechanisms are important for maintaining DNA integrity and preventing carcinogenesis. Recent lung cancer studies have focused on identifying the effects of single nucleotide polymorphisms (SNPs) in candidate genes, among which DNA repair genes are increasingly being studied. Genetic variations in DNA repair genes are thought to modulate DNA repair capacity and are suggested to be related to lung cancer risk. We identified a sufficient number of epidemiologic studies on lung cancer to conduct a meta-analysis for genetic polymorphisms in nucleotide excision repair pathway genes, focusing on xeroderma pigmentosum group A (XPA), excision repair cross complementing group 1 (ERCC1), ERCC2/XPD, ERCC4/XPF and ERCC5/XPG. We found an increased risk of lung cancer among subjects carrying the ERCC2 751Gln/Gln genotype (odds ratio (OR) = 1.30, 95% confidence interval (CI) = 1.14 - 1.49). We found a protective effect of the XPA 23G/G genotype (OR = 0.75, 95% CI = 0.59 - 0.95). Considering the data available, it can be conjectured that if there is any risk association between a single SNP and lung cancer, the risk fluctuation will probably be minimal. Advances in the identification of new polymorphisms and in high-throughput genotyping techniques will facilitate the analysis of multiple genes in multiple DNA repair pathways. Therefore, it is likely that the defining feature of future epidemiologic studies will be the simultaneous analysis of large samples.

ERCC1 codon 118 polymorphism is a predictive factor for the tumor response to oxaliplatin/5-fluorouracil combination chemotherapy in patients with advanced colorectal cancer

PURPOSE

The aim of our study was to assess whether the polymorphism of the nucleotide excision repair enzyme, excision repair cross-complementing rodent repair deficiency, complementation group 1 (ERCC1), had an effect on the tumor response in patients treated with standard chemotherapy regimens for a metastatic colorectal cancer. We have studied the synonymous polymorphism that causes a single nucleotide change C to T at codon 118 converting a codon of common usage (AAC) to a less used codon (AAT), both coding asparagine. This change results in a decreased ERCC1 gene expression, which impairs repair activity.

EXPERIMENTAL DESIGN

Ninety-one patients with a median age of 55.1 years treated for a metastatic colorectal cancer were included in our retrospective study. The ERCC1 polymorphism was analyzed in the normal tissue of all patients.

RESULTS

Twenty (22%) were homozygous for AAC codon (C/C genotype), 30 were (33%) homozygous for AAT codon (T/T genotype), and 41 (45%) were heterozygous (C/T genotype). The objective response rate to oxaliplatin in combination with 5-fluorouracil (5-FU) was significantly higher in the T/T genotype group compared with the C/T and the C/C genotype groups (61.9%, 42.3%, and 21.4%, respectively; P = 0.018). By contrast, no significant difference was observed when patients were treated with either 5-FU alone (45%, 29.2%, and 33.3%, respectively; P = 0.407) or in combination with irinotecan (46.1%, 25.0%, and 27.3%, respectively; P = 0.305).

CONCLUSIONS

Our observations allowed us to define the first useful predictive criterion for oxaliplatin/5-FU response in patients with metastatic colorectal cancer.

Polymorphisms in ERCC1 and Grade 3 or 4 Toxicity in Non–Small Cell Lung Cancer Patients

PURPOSE

ERCC1 is a lead enzyme in the nucleotide excision repair pathway of DNA repair. Polymorphisms have been identified in the ERCC1 gene, the C8092A and codon 118 polymorphisms, which may lead to an altered capacity to regenerate damaged normal tissue and greater treatment-related toxicity.

EXPERIMENTAL DESIGN

Using logistic regression models, we evaluated the ERCC1 C8092A and codon 118 polymorphisms and their association with the occurrence of grade 3 or 4 toxicity in 214 stage III and IV non-small cell lung cancer patients treated first line with platinum-based chemotherapy. Adjusting covariates were performance status and type of treatment regimen.

RESULTS

There was no statistically significant association between either the C8092A or codon 118 polymorphism and overall or hematologic grade 3 or 4 toxicity. However, carrying at least one variant ERCC1 C8092A allele was associated with a significantly increased risk of grade 3 or 4 gastrointestinal toxicity (adjusted odds ratio, 2.33; 95% confidence interval, 1.07-5.05; P = 0.03).

CONCLUSIONS

Adjusting for performance status and type of treatment regimen, carrying at least one ERCC1 8092A allele is associated with a >2-fold increase in grade 3 or 4 gastrointestinal toxicity among platinum-treated non-small cell lung cancer patients.