Pharmacogenetic role of ERCC1 genetic variants in treatment response of platinum-based chemotherapy among advanced non-small cell lung cancer patients

Genetic Variants Associated With Response to Platinum-Based Chemotherapy in Non-Small Cell Lung Cancer Patients: A Field Synopsis and Meta-Analysis

Background: Publications on the associations of genetic variants with the response to platinum-based chemotherapy (PBC) in NSCLC patients have surged over the years, but the results have been inconsistent. Here, a comprehensive meta-analysis was conducted to combine eligible studies for a more accurate assessment of the pharmacogenetics of PBC in NSCLC patients. Methods: Relevant publications were searched in PubMed, Scopus, and Web of Science databases through 15 May 2021. Inclusion criteria for eligible publications include studies that reported genotype and allele frequencies of NSCLC patients treated with PBC, delineated by their treatment response (sensitive vs. resistant). Publications on cell lines or animal models, duplicate reports, and non-primary research were excluded. Epidemiological credibility of cumulative evidence was assessed using the Newcastle-Ottawa Scale (NOS) and Venice criteria. Begg's and Egger's tests were used to assess publication bias. Cochran's Q-test and I2 test were used to calculate the odds ratio and heterogeneity value to proceed with the random effects or fixed-effects method. Venice criteria were used to assess the strength of evidence, replication methods and protection against bias in the studies. Results: A total of 121 publications comprising 29,478 subjects were included in this study, and meta-analyses were performed on 184 genetic variants. Twelve genetic variants from 10 candidate genes showed significant associations with PBC response in NSCLC patients with strong or moderate cumulative epidemiological evidence (increased risk: ERCC1 rs3212986, ERCC2 rs1799793, ERCC2 rs1052555, and CYP1A1 rs1048943; decreased risk: GSTM1 rs36631, XRCC1 rs1799782 and rs25487, XRCC3 rs861539, XPC rs77907221, ABCC2 rs717620, ABCG2 rs2231142, and CDA rs1048977). Bioinformatics analysis predicted possible damaging or deleterious effects for XRCC1 rs1799782 and possible low or medium functional impact for CYP1A1 rs1048943. Conclusion: Our results provide an up-to-date summary of the association between genetic variants and response to PBC in NSCLC patients.

Genetic polymorphisms as potential pharmacogenetic biomarkers for platinum-based chemotherapy in non-small cell lung cancer

Platinum-based chemotherapy (PBC) is a widely used treatment for various solid tumors, including non-small cell lung cancer (NSCLC). However, its efficacy is often compromised by the emergence of drug resistance in patients. There is growing evidence that genetic variations may influence the susceptibility of NSCLC patients to develop resistance to PBC. Here, we provide a comprehensive overview of the mechanisms underlying platinum drug resistance and highlight the important role that genetic polymorphisms play in this process. This paper discussed the genetic variants that regulate DNA repair, cellular movement, drug transport, metabolic processing, and immune response, with a focus on their effects on response to PBC. The potential applications of these genetic polymorphisms as predictive indicators in clinical practice are explored, as are the challenges associated with their implementation.

Current Insights into Interethnic Variability in Testicular Cancers: Population Pharmacogenetics, Clinical Trials, Genetic Basis of Chemotherapy- Induced Toxicities and Molecular Signal Transduction

Testicular cancer is an aggressive malignancy with a rising incidence rate across the globe. Testicular germ cell tumors are the most commonly diagnosed cancers, and surgical removal of the testes is often a radical necessity along with chemotherapy and radiotherapy. While seminomas are receptive to radiotherapy as well as chemotherapy, non-seminomatous germ cell tumors respond to chemotherapy only. Due to the singular nature of testicular cancers with associated orchiectomy and mortality, it is important to study the molecular basis and genetic underpinnings of this group of cancers across male populations globally. In this review, we shed light on the population pharmacogenetics of testicular cancer, pediatric and adult tumors, current clinical trials, genetic determinants of chemotherapy-induced toxicity in testicular cancer, as well as the molecular signal transduction pathways operating in this malignancy. Taken together, our discussions will help in enhancing our understanding of genetic factors in testicular carcinogenesis and chemotherapy-induced toxicity, augment our knowledge of this aggressive cancer at the cellular and molecular level, as well as improve precision medicine approaches to combat this disease.

Pharmacogenetics of platinum-based chemotherapy in non-small cell lung cancer: predictive validity of polymorphisms of ERCC1

INTRODUCTION

The efficacy of platinum-based chemotherapy for patients with non-small cell lung cancer (NSCLC) is limited by chemoresistance. Platinum drugs damage DNA by introducing intrastrand and interstrand crosslinks which result in cell death. Excision repair cross-complementing 1 (ERCC1) is a member of the nucleotide excision repair (NER) pathway which erases such defects. Single nucleotide polymorphisms (SNPs) in ERCC1 impair this activity and have been suggested to predict the response to chemotherapy. Area covered: Among the polymorphisms of proteins involved in uptake, metabolism, cytotoxicity and efflux of platinum drugs, codon 118 C/T and C8092A in ERCC1 are the best characterized SNPs studied for their predictive power. Here, the divergent results for studies of these markers in NSCLC are summarized and the reasons for this contradictory data discussed. Expert opinion: Cytotoxicity of platinum compounds comprise complex cellular processes for which DNA repair may not constitute the rate limiting step. These drugs are administered as doublets to histologically diverse patients and, furthermore, the NER pathway in ERCC1 wildtype cohorts may be still impaired by the chemotherapeutics applied. At present, assessment of a limited number of polymorphism in DNA repair proteins is not reliably associated with response to treatment in NSCLC patients.

ERCC1_202 Is A Prognostic Biomarker in Advanced Stage Non-Small Cell Lung Cancer Patients Treated with Platinum-Based Chemotherapy

Purpose: To develop a qPCR method to examine the 202 isoform of excision repair cross-complementation group 1 (ERCC1_202) and to evaluate its clinical utility as a predictive biomarker for platinum-based chemotherapy in non-small cell lung cancer (NSCLC). Methods: The relative complementary DNA (cDNA) quantification for ERCC1_202 was conducted using a fluorescence-based, real-time detection method and β-actin was used as a reference gene. Results: A strong correlation was observed between ERCC1_202 mRNA and ERCC1 mRNA levels in NSCLC cells (P < 0.001). 28 patients completed this research. Our results implied that as ERCC1_202 levels increased, the risk of progression (HR = 4.296, P = 0.011) and death (HR = 6.503, P = 0.001) increased. At multivariate analysis, high expression of ERCC1_202 was shown to be an independent predictive factor for time to progression (P = 0.047), and progression-free survival (P = 0.014). However, the high expression of ERCC1_202 was not an independent predictive factor for response (P = 0.324). Conclusions: This study suggests that the efficacy of platinum-based chemotherapy can be improved when customized according to the expression of ERCC1_202.

Genetic Polymorphisms and Platinum-based Chemotherapy Treatment Outcomes in Patients with Non-Small Cell Lung Cancer: A Genetic Epidemiology Study Based Meta-analysis

Data regarding genetic polymorphisms and platinum-based chemotherapy (PBC) treatment outcomes in patients with NSCLC are published at a growing pace, but the results are inconsistent. This meta-analysis integrated eligible candidate genes to better evaluate the pharmacogenetics of PBC in NSCLC patients. Relevant studies were retrieved from PubMed, Chinese National Knowledge Infrastructure and WANFANG databases. A total of 111 articles comprising 18,196 subjects were included for this study. The associations of genetic polymorphisms with treatment outcomes of PBC including overall response rate (ORR), overall survival (OS) and progression-free survival (PFS) were determined by analyzing the relative risk (RR), hazard ration (HR), corresponding 95% confidence interval (CI). Eleven polymorphisms in 9 genes, including ERCC1 rs11615 (OS), rs3212986 (ORR), XPA rs1800975 (ORR), XPD rs1052555 (OS, PFS), rs13181 (OS, PFS), XPG rs2296147 (OS), XRCC1 rs1799782 (ORR), XRCC3 rs861539 (ORR), GSTP1 rs1695 (ORR), MTHFR rs1801133 (ORR) and MDR1 rs1045642 (ORR), were found significantly associated with PBC treatment outcomes. These variants were mainly involved in DNA repair (EXCC1, XPA, XPD, XPG, XRCC1 and XRCC3), drug influx and efflux (MDR1), metabolism and detoxification (GSTP1) and DNA synthesis (MTHFR), and might be considered as potential prognostic biomarkers for assessing objective response and progression risk in NSCLC patients receiving platinum-based regimens.

Prevalence of CTR1 and ERCC1 Polymorphisms and Response of Biliary Tract Cancer to Gemcitabine-Platinum Chemotherapy

Purpose:

Biliary tract cancer (BTC)is an aggressive disease with a poor prognosis. Most patients are diagnosed at an advanced stage for which curative surgery is not possible and gemcitabine-platinum chemotherapy is the treatment of choice for advanced cases. Several studies had focused on biomarkers to predict response from platinum drugs in lung cancer, but information is limited for BTC. In this study, two single nucleotide polymorphisms (SNPs) in the copper transporter (CTR1) and excision repair cross-complementary group 1 (ERCC1) genes were investigated as predictive biomarkers of objective response to gemcitabine-platinum.

Methods:

This cohort study aimed to assess any associations of genetic polymorphisms of these proteins active in drug pathway with treatment response in advanced BTC patients. Twenty six patients were enrolled. DNA was extracted from peripheral blood and genetic polymorphisms were assessed by Taqman allelic discrimination assay. Response was evaluated according to RECIST version 1.1. Results: For the CTR1 polymorphism, GT was the most common genotype (61.5%) followed by GG (34.6%), and TT (3.8%). For the ERCC1 polymorphism, only 2 genotypes were found, CC and CT at 57.7% and 42.3%, respectively. Genetic polymorphisms were not found to be singly associated with response. However, when the 2 genetic polymorphisms were combined, GG/CC showed a higher response rate than the others (p=0.018, Fisher’s Exact Test).

Conclusion:

This is the first study to show an association between CTR1 and ERCC1 polymorphisms and response to gemcitabine-platinum in advanced BTC patients. These polymorphisms might be used as biomarkers to predict response in such cases in the future.

Pharmacogenomics of platinum-based chemotherapy in non-small cell lung cancer: focusing on DNA repair systems

Drug therapy for non-small cell lung cancer consists mainly of platinum-based chemotherapy regimens. However, toxicity, drug resistance, and high risk of death have been seen in the clinic, which means there is a need for optimizing the use of medications. Platinum resistance could be mediated by a series of DNA repair pathways, and therefore, these pathways should be taken into account for optimizing drug using. The goal of pharmacogenomics is to elucidate genetic factors, such as DNA repair genes, which might underlie drug efficacy and effectiveness, and to improve therapeutic effects or guide personalized therapy as well. Here, we reviewed the current knowledge of pharmacogenomic data on DNA repair systems and examined whether they could be further translated into the clinic with evidence-based perspectives.

ERCC1 Expression-Based Randomized Phase II Study of Gemcitabine/Cisplatin Versus Irinotecan/Cisplatin in Patients with Advanced Non-small Cell Lung Cancer

Purpose

We evaluated the clinical utility of excision repair cross-complementation group 1 (ERCC1) expression as a predictive biomarker for platinum-based chemotherapy in advanced non-small cell lung cancer (NSCLC).

Materials and Methods

Eligible patients were randomly assigned to the GP (gemcitabine 1,250 mg/m² on days 1 and 8, and cisplatin 75 mg/m² on day 1 every 3 weeks) or IP (irinotecan 65 mg/m² and cisplatin 30 mg/m² on days 1 and 8 every 3 weeks) arm. The primary goal of this study was to compare the response rate (RR) of the GP and IP arms according to the ERCC1 expression level.

Results

A total of 279 patients were randomly assigned to the GP (n=139) and IP (n=140) arms, among which 63% were ERCC1-positive and 268 patients were assessable for the RR. The GP and IP arms did not differ significantly with respect to the RR (29.8% vs. 27.0%, respectively; p=0.082), median progression-free survival (PFS; 4.5 months vs. 3.9 months, respectively; p=0.117), and overall survival (OS; 16.5 months vs. 16.7 months, respectively; p=0.313). When comparing the efficacy between the ERCC1-positive and ERCC1-negative groups, there was no significant difference in the RR (GP, 28.2% vs. 32.6%, respectively, p=0.509; IP, 30.2% vs. 21.6%, respectively, p=0.536), median PFS (GP, 4.6 months vs. 5.0 months, respectively, p=0.506; IP, 3.9 months vs. 3.7 months, respectively, p=0.748), or median OS (GP, 18.6 months vs. 11.9 months, respectively, p=0.070; IP, 17.5 months vs. 14.0 months, respectively, p=0.821).

Conclusion

Immunohistochemical analysis of the ERCC1 expression level did not differentiate the efficacy of platinum-based chemotherapy in advanced NSCLC.

Pharmacogenomics of platinum-based chemotherapy sensitivity in NSCLC: toward precision medicine

Lung cancer is one of the leading causes of cancer-related death in the world. Platinum-based chemotherapy is the first-line treatment for non-small-cell lung cancer (NSCLC), however, the therapeutic efficiency varies remarkably among individuals. A large number of pharmacogenomics studies aimed to identify genetic variations which can be used to predict platinum response. Those studies are leading NSCLC treatment to the new era of precision medicine. In the current review, we provided a comprehensive update on the main recent findings of genetic variations which can be used to predict platinum sensitivity in the NSCLC patients.

The genetic variations in DNA repair genes ERCC2 and XRCC1 were associated with the overall survival of advanced non-small-cell lung cancer patients

It was reported that DNA repair can confer cancer cell resistance to therapeutic treatments by activating antiapoptotic cellular defense. We hypothesized that genetic variants of DNA repair genes may be associated with lung cancer prognosis. Seventeen tagging single‐nucleotide polymorphism (tagSNPs) selected from 12 DNA repair genes were genotyped in 280 advanced non‐small‐cell lung cancer (NSCLC) patients by TaqMan assay. The associations of these SNPs and overall survival of advanced NSCLC patients were investigated. Advanced NSCLC patients carrying ERCC2 rs50872 CT+TT genotypes had significantly longer median survival time (MST) and decreased death risk than patients with rs50872 CC genotype [log‐rank P = 0.031; adjusted HR(95% CI) = 0.73 (0.55–0.98), P = 0.033]. These effects were mainly seen among younger patients (≤65 years old) [HR(95% CI) = 0.57 (0.37–0.87), P = 0.010], patients without surgery [HR(95% CI) = 0.68 (0.47–0.98), P = 0.036] but with chemotherapy [HR(95% CI) = 0.64 (0.46–0.91), P = 0.012] or radiotherapy [HR(95% CI) = 0.58 (0.38–0.89), P = 0.013]. Meanwhile, compared to advanced NSCLC patients with rs25487 GG genotype, patients carrying XRCC1 rs25487 GA+AA genotypes had significantly shorter MST (MST = 11.7 vs. 16.7, log‐rank P = 0.048). In addition, advanced NSCLC patients carrying the ERCC2 rs50872 CC in combination with XRCC1 rs25487 GA+AA genotype had the shortest MST (11.2 month) and highest death risk [HR(95% CI) = 1.70 (1.15–2.52), P = 0.008] when compared with those carrying rs50872 CT+TT and rs25487 GG genotype (MST = 22.0 month). The ERCC2 rs50872 T allele was associated with favorable but XRCC1 rs25487 A allele with bad survival for advanced NSCLC in Chinese population, which may offer novel biomarkers for predicting clinical outcomes.

Pharmacogenomics of cisplatin sensitivity in non-small cell lung cancer

Cisplatin, a platinum-based chemotherapeutic drug, has been used for over 30 years in a wide variety of cancers with varying degrees of success. In particular, cisplatin has been used to treat late stage non-small cell lung cancer (NSCLC) as the standard of care. However, therapeutic outcomes vary from patient to patient. Considerable efforts have been invested to identify biomarkers that can be used to predict cisplatin sensitivity in NSCLC. Here we reviewed current evidence for cisplatin sensitivity biomarkers in NSCLC. We focused on several key pathways, including nucleotide excision repair, drug transport and metabolism. Both expression and germline DNA variation were evaluated in these key pathways. Current evidence suggests that cisplatin-based treatment could be improved by the use of these biomarkers.

Systems biology of cisplatin resistance: past, present and future

The platinum derivative cis-diamminedichloroplatinum(II), best known as cisplatin, is currently employed for the clinical management of patients affected by testicular, ovarian, head and neck, colorectal, bladder and lung cancers. For a long time, the antineoplastic effects of cisplatin have been fully ascribed to its ability to generate unrepairable DNA lesions, hence inducing either a permanent proliferative arrest known as cellular senescence or the mitochondrial pathway of apoptosis. Accumulating evidence now suggests that the cytostatic and cytotoxic activity of cisplatin involves both a nuclear and a cytoplasmic component. Despite the unresolved issues regarding its mechanism of action, the administration of cisplatin is generally associated with high rates of clinical responses. However, in the vast majority of cases, malignant cells exposed to cisplatin activate a multipronged adaptive response that renders them less susceptible to the antiproliferative and cytotoxic effects of the drug, and eventually resume proliferation. Thus, a large fraction of cisplatin-treated patients is destined to experience therapeutic failure and tumor recurrence. Throughout the last four decades great efforts have been devoted to the characterization of the molecular mechanisms whereby neoplastic cells progressively lose their sensitivity to cisplatin. The advent of high-content and high-throughput screening technologies has accelerated the discovery of cell-intrinsic and cell-extrinsic pathways that may be targeted to prevent or reverse cisplatin resistance in cancer patients. Still, the multifactorial and redundant nature of this phenomenon poses a significant barrier against the identification of effective chemosensitization strategies. Here, we discuss recent systems biology studies aimed at deconvoluting the complex circuitries that underpin cisplatin resistance, and how their findings might drive the development of rational approaches to tackle this clinically relevant problem.

Nucleotide excision repair gene polymorphisms and prognosis of non-small cell lung cancer patients receiving platinum-based chemotherapy: A meta-analysis based on 44 studies

Genetic variations are linked to DNA repair ability and varied drug metabolism that largely affects the prognosis of antineoplastic agents, including platinum. The purpose of the present meta-analysis was to determine the roles of the genetic variants of the nucleotide excision repair genes on the prognosis of platinum-based chemotherapy in patients with non-small cell lung cancer (NSCLC). A meta-analysis was performed, including 44 original studies with a total number of 5,944 patients with NSCLC according to the search strategy. The tumor responses [complete response, partial response, stable disease (SD) and progressive disease (PD)] were estimated and the Stata package was used for the comprehensive quantitative analyses. The results showed that the XPG C46T polymorphism was significantly associated with tumor chemotherapy when SD or PD was considered as a non-response [TT vs. CC: risk ratio (RR), 1.31; 95% confidence interval (CI), 1.14-1.5; and P=0.00; TT/CT vs. CC: RR, 1.23; 95% CI, 1.11-1.36; and P=0.00; and TT vs.

CC/CT

RR, 1.22; 95% CI, 1.11-1.36; and P=0.00]. No significant association between the ERCC1 C118T/C8092A XPDLys751Gln and XPA A23G polymorphisms and tumor response was found. There was also no evidence found to support the use of the ERCC1 C118T/C8092A XPDLys751Gln and XPA A23G polymorphisms as prognostic predictors of platinum-based chemotherapies in NSCLC in the meta-analysis. For the XPG C46T polymorphisms, a significant association with an objective response was detected. Multiple and large-scale studies are required to further investigate the association between biomarkers and tumor prognosis.

Predicting the outcome of platinum-based chemotherapies in epithelial ovarian cancer using the 8092C/A polymorphism of ERCC1: a meta-analysis

BACKGROUND

In the present study, we performed this meta-analysis to estimate the association between excision repair cross-complementation group 1 (ERCC1) gene polymorphism and clinical resistance to platinum-based chemotherapy in the patients with epithelial ovarian cancer (EOC).

METHODS

A total of 10 studies consist of 1479 EOC patients relating ERCC1 rs11615C/T and rs3212986C/A polymorphisms to the response of platinum-based chemotherapy were included in this meta-analysis.

RESULTS

The analysis showed that the AA genotype of the rs3212986C/A polymorphism in ERCC1 was associated with progression-free survival of EOC patients (HR = 1.39, 95% CI = 1.12-1.73) and that the CA or AA genotypes could influence overall survival (HR = 1.28, 95% CI = 1.05-1.56; and HR = 1.55, 95% CI = 1.17∼2.05, respectively).

CONCLUSIONS

The ERCC1 rs3212986C/A polymorphism may be a useful prognostic marker in platinum-based treatment of EOC.

Expression levels of ERCC1 and RRM1 mRNA and clinical outcome of advanced non-small cell lung cancer

Objective: We conducted a study to understand the genetic effect of ERCC1 and RRM1 on the chemotherapy response and clinical outcome of Non-Small Cell Lung Cancer (NSCLC).

Methods: The relative cDNA quantification for ERCC1 and RRM1 was conducted using a fluorescence-based real-time detection method among 294 NSCLC patients.

Results: Compared with the internal reference gene β-action, the median levels of ERCC1 and RRM1 expression were 2.43×10^-2 and 0.11×10^-2, respectively. Our study showed response to platinum-containing regimen chemotherapy was high in those with high ERCC1 expression, and the OR (95% CI) were 1.73(1.06-2.81). An apparently high response to chemotherapy was decreased when patients were carrying both high expression of ERCC1 and RRM1, with OR (95% CI) of 2.57(1.21-4.90). Patients with high expression of ERCC1 were associated with a longer OS by multivariate Cox proportional hazards model. Moreover, those carrying both high levels of ERCC1 and RRM1 were seem to have a longer OS when compared with those with low expression (HR=0.31, 95% CI=0.13-0.62 for OS).

Conclusion: This observation could be used in personalized chemotherapy, increase the response rate and prolonged survival time, and could encourage to explore the predictive value of other genes.

The association between the ERCC1/2 polymorphisms and the clinical outcomes of the platinum-based chemotherapy in non-small cell lung cancer (NSCLC): a systematic review and meta-analysis

The relationship between the ERCC1/2 single nucleotide polymorphisms (SNPs) and the clinical outcomes of the platinum-based chemotherapy in the non-small cell lung cancer (NSCLC) is still inconsistent and inconclusive despite extensive investigations have been conducted to address this question. In this meta-analysis, we aim to further explore the prognostic value of the ERCC1/2 SNPs in NSCLC by analyzing all currently available evidences. Relevant studies were searched in PubMed, Embase, and China National Knowledge Infrastructure. The inclusion criteria were platinum-based chemotherapy in NSCLC patients and evaluation of clinical outcomes in relation to the ERCC1 C118T, ERCC1 C8092A, ERCC2 Asp312Asn, and ERCC2 Lys751Gln. Clinical outcomes analyzed in this study included the overall response rate, overall survival (OS), and progression-free survival (PFS). Odds ratio (OR) or hazard ratio (HR) with 95% confidence interval (CI) were calculated to examine the risk or hazard associated with each SNP. A total of 46 studies including 9,407 NSCLC patients were qualified for this meta-analysis. For ERCC1 C118T, the T allele was associated with a poor OS (HR = 1.35, 95% CI = 1.04-1.75); for ERCC2 Asp312Asn, the Asn variant was linked to an unfavorable OS (HR = 2.07, 95% CI = 1.11-3.88); and for ERCC2 Lys751Gln, patients with the Gln variant have a worse OS (HR = 1.22, 95% CI = 1.05-1.41) and PFS (HR = 1.35, 95% CI = 1.07-1.71). In addition, the main findings of the ERCC1/2 SNPs on chemotherapy toxicity were also summarized. This meta-analysis suggested that the ERCC1 C118T, ERCC2 Asp312Asn, and Lys751Gln may be useful biomarkers to predict the clinical outcomes of the platinum-based chemotherapy in NSCLC patients.

Functional IL-23R rs10889677 genetic polymorphism and risk of multiple solid tumors: a meta-analysis

Interleukin-23 receptor (IL23R) can interact with IL-23 and, thus, is involved in the T-helper 17 (Th17) cell-mediated inflammatory process as well as tumorigenesis. Recently, a functional single nucleotide polymorphism (SNP) rs10889677 has been identified in the 3'-untranslated region of IL-23R. It has been showed that the rs10889677AC SNP could increase the binding affinity of microRNA let-7f and downregulate IL-23R expression. Several case-control studies have examined the association between this SNP and genetic susceptibility of multiple solid tumors. However, the conclusions are conflicting. Therefore, we conducted this meta-analysis to systematically study the role of this functional IL-23R SNP in development of multiple solid tumors. There are a total of 5 studies are eligible (6731 cases and 7296 healthy controls). Either fixed-effect model or random-effect model was used to calculate pooled odds ratios (ORs) and the 95% confidence interval (95% CI). Significant association between this functional rs10889677 genetic variant and risk of multiple solid tumors were observed (CC genotype vs. AA genotype: OR = 0.59, 95% CI = 0.53-0.66, P < 0.001). These findings demonstrated that the IL-23R rs10889677 genetic variant might play an important part during malignant transformation of multiple solid tumors.

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.

Are race-specific ERCC1 haplotypes in melanoma cases versus controls related to the predictive and prognostic value of ERCC1 N118N?

OBJECTIVES

Although it does not alter the ERCC1 phenotype, the ERCC1 500C>T (rs11615) polymorphism has undergone a myriad of investigations into its role as a marker for nucleotide excision repair (NER) function in different races, diseases and treatment outcomes. The goal of our study was to test the hypothesis that 500C>T is in linkage disequilibrium (LD) with causative alleles, and that these haplotypes are more frequent in Caucasians with melanoma than in healthy Caucasians or African Americans.

DESIGN

In this case-control study, we selected race-specific ERCC1 single-nucleotide polymorphism (SNPs), conducted LD analysis with ERCC1 500C>T and compared the frequency of ERCC1 diplotypes in Caucasians with melanoma (n=165), healthy Caucasians (n=150) and healthy African Americans (n=159). The haplotype was further studied using a fusion gene containing multiple ERCC1 SNPs.

SETTING

Large cancer institute in the USA.

PARTICIPANTS

A total of 165 Caucasian melanoma patients, 159 healthy Caucasian controls and 159 African American healthy controls. Men and women were enrolled in the clinical trial; however, since the screening trial included prostate cancer screening in addition to screening for other cancers, only male controls were available.

OUTCOME MEASURES

The outcome measures were melanoma risk in Caucasians, and LD between ERCC1 SNP, N118N and other race-specific allelic variants.

RESULTS

When compared to ERCC1 500C>T alone, a race-specific three-SNP variant haplotype in ERCC1 (comprised of rs11615, rs3212950 and rs3212948) was even more frequent in Caucasians with melanoma than in healthy Caucasians (p=0.0034) or African Americans (p<0.0001). A plasmid containing the variant haplotype was not differentially expressed.

CONCLUSIONS

We demonstrate that ERCC1 500C>T participates in a previously characterised cancer-risk haplotype found more frequently in Caucasians, while LD is weak in African Americans; this haplotype appears to also be related to melanoma. It is therefore likely that ERCC1 500C>T is only a valid NER, disease or treatment outcome marker in Caucasians.

Genetic variants in genes involved in mechanisms of chemoresistance to anticancer drugs

Refractoriness to the pharmacological treatment of cancer is dependent on the expression levels of genes involved in mechanisms of chemoresistance and on the existence of genetic variants that may affect their function. Thus, changes in genes encoding solute carriers may account for considerable inter-individual variability in drug uptake and the lack of sensitivity to the substrates of these transporters. Moreover, changes in proteins involved in drug export can affect their subcellular localization and transport ability and hence may also modify the bioavailability of antitumor agents. Regarding pro-drug activation or drug inactivation, genetic variants are responsible for changes in the activity of drug-metabolizing enzymes, which affect drug clearance and may determine the lack of response to anticancer chemotherapy. The presence of genetic variants may also decrease the sensitivity to pharmacological agents acting through molecular targets or signaling pathways. Recent investigations suggest that changes in genes involved in DNA repair may affect the response to platinum-based drugs. Since most anticancer agents activate cell death pathways, the evasion of apoptosis plays an important role in chemoresistance. Several genetic variants affecting death-receptor pathways, the mitochondrial pathway, downstream caspases and their natural modulators, and the p53 pathway, whose elements are mutated in more than half of tumors, and survival pathways, have been reported. The present review summarizes the available data regarding the role of genetic variants in the different mechanisms of chemoresistance and discusses their potential impact in clinical practice and in the development of tools to predict and overcome chemoresistance.

Meta-analysis on pharmacogenetics of platinum-based chemotherapy in non small cell lung cancer (NSCLC) patients

AIM

To determine the pharmacogenetics of platinum-based chemotherapy in Non Small Cell Lung Cancer (NSCLC) patients.

METHODS

Publications were selected from PubMed, Cochrane Library and ISI Web of Knowledge. A meta-analysis was conducted to determine the association between genetic polymorphisms and platinum-based chemotherapy by checking odds ratio (OR) and 95% confidence interval (CI).

RESULTS

Data were extracted from 24 publications, which included 11 polymorphisms in 8 genes for meta-analysis. MDR1 C3435T (OR = 1.97, 95% CI: 1.11-3.50, P = 0.02), G2677A/T (OR = 2.61, 95% CI: 1.44-4.74, P = 0.002) and GSTP1 A313G (OR = 0.32, 95% CI: 0.17-0.58, P = 0.0002) were significantly correlated with platinum-based chemotherapy in Asian NSCLC patients.

CONCLUSION

Attention should be paid to MDR1 C3435T, G2677A/T and GSTP1 A313G for personalized chemotherapy treatment for NSCLC patients in Asian population in the future.