Association studies of ERCC1 polymorphisms with lung cancer susceptibility: a systematic review and meta-analysis

Current and Emerging Diagnostic, Prognostic, and Predictive Biomarkers in Head and Neck Cancer

Head and neck cancers (HNC) are a biologically diverse set of cancers that are responsible for over 660,000 new diagnoses each year. Current therapies for HNC require a comprehensive, multimodal approach encompassing resection, radiation therapy, and systemic therapy. With an increased understanding of the mechanisms behind HNC, there has been growing interest in more accurate prognostic indicators of disease, effective post-treatment surveillance, and individualized treatments. This chapter will highlight the commonly used and studied biomarkers in head and neck squamous cell carcinoma.

Tumor-associated microbiome features of metastatic colorectal cancer and clinical implications

Background

Colon microbiome composition contributes to the pathogenesis of colorectal cancer (CRC) and prognosis. We analyzed 16S rRNA sequencing data from tumor samples of patients with metastatic CRC and determined the clinical implications.

Materials and methods

We enrolled 133 patients with metastatic CRC at St. Vincent Hospital in Korea. The V3-V4 regions of the 16S rRNA gene from the tumor DNA were amplified, sequenced on an Illumina MiSeq, and analyzed using the DADA2 package.

Results

After excluding samples that retained <5% of the total reads after merging, 120 samples were analyzed. The median age of patients was 63 years (range, 34-82 years), and 76 patients (63.3%) were male. The primary cancer sites were the right colon (27.5%), left colon (30.8%), and rectum (41.7%). All subjects received 5-fluouracil-based systemic chemotherapy. After removing genera with <1% of the total reads in each patient, 523 genera were identified. Rectal origin, high CEA level (≥10 ng/mL), and presence of lung metastasis showed higher richness. Survival analysis revealed that the presence of Prevotella (p = 0.052), Fusobacterium (p = 0.002), Selenomonas (p<0.001), Fretibacterium (p = 0.001), Porphyromonas (p = 0.007), Peptostreptococcus (p = 0.002), and Leptotrichia (p = 0.003) were associated with short overall survival (OS, <24 months), while the presence of Sphingomonas was associated with long OS (p = 0.070). From the multivariate analysis, the presence of Selenomonas (hazard ratio [HR], 6.35; 95% confidence interval [CI], 2.38-16.97; p<0.001) was associated with poor prognosis along with high CEA level.

Conclusion

Tumor microbiome features may be useful prognostic biomarkers for metastatic CRC.

Association between ERCC1 Gene Polymorphism (rs11615) and Colorectal Cancer Susceptibility: A Meta-Analysis of Medical Image Fusion and Safety Applications

Colorectal cancer (CRC) is a malignant tumor of the colorectal mucosa epithelial tissue transformed. The fusion of data for medical imaging has become a central issue in such biomedical applications as image-guided surgery and radiotherapy. Currently, CRC has been one of the most threatening tumors affecting people's health worldwide. The excision repair cross-complementation group 1 (ERCC1) is a key enzyme for nucleotide excision repair (NER). Emerging epidemiological studies have indicated that the presence of colorectal cancer (CRC) may be relevant to the ERCC1 rs11615 genetic polymorphism. However, the results of ERCC1 rs11615 on CRC in these studies are controversial. We searched PubMed, Web of Science, Embase, CNKI, and CBM databases for the effects of ERCC1 rs11615 variant on CRC development. There was no meta-analysis focused on the diagnosis of colorectal cancer with ERCC1 rs11615 variant. We creatively carried out a meta-analysis of nine case-control studies and used Stata (version 12.0) software to integrate the pooled odds ratios (ORs) corresponding to a 95% confidence interval (CI) of overall and subgroup analysis. Our results suggest that a significant correlation was observed between rs11615 and the susceptibility of CRC OR 95% CI = 1.13 (1.04-1.23) under an allele genetic model and OR 95% CI = 1.14 (1.01-1.30) under a dominant genetic model for overall CRC. Significant statistical difference was also noted in Asians rather than Caucasians based on the ethnicity subgroups. These results suggested that there is a certain association between rs11615 and the susceptibility of colorectal cancer in the Asian populations.

Association of ERCC1 rs11615 Polymorphism with the Risk of Cervical Cancer Especially in Chinese Populations: A Meta-Analysis

Abnormalities of the ERCC1 gene can affect DNA repair pathways, thereby having a vital effect on genomic stability. A growing amount of case-control studies have focused on making an investigation of the association between ERCC1 rs11615 polymorphism and cervical cancer susceptibility. However, the controversial results have raised concerns. To draw a more accurate conclusion, six studies were elaborately selected from the electronic databases for this meta-analysis, with 753 cervical cancer cases and 851 healthy controls. We applied pooled ORs combined with 95% CIs to test the potential associations. Significant associations were revealed in Chinese populations (T vs C: $\text{OR}=1.557$ and $95\%\text{CI}=1.234–1.966$ ; TT vs CC: $\text{OR}=3.175$ and $95\%\text{CI}=1.754–5.748$ ; TT/CT vs CC: $\text{OR}=1.512$ and $95\%\text{CI}=1.126–\mathrm{2,031}$ ; and TT vs CT/CC: $\text{OR}=2.836$ and $95\%\text{CI}=1.592–5.051$ ). Even when the studies deviating from HWE were excluded, an increased cervical cancer susceptibility was observed in Chinese. These results disclose that there is an obvious correlation between the risk of cervical cancer and ERCC1 rs11615 polymorphism, especially in Chinese populations, and the T variant is the risky one. Also, our findings need further studies to validate.

Radon, Tobacco Exposure and Non-Small Cell Lung Cancer Risk Related to BER and NER Genetic Polymorphisms

INTRODUCTION

Tobacco consumption and radon exposure are considered the first and second most common causes of lung cancer, respectively. The aim of this study was to analyze both whether selected genetic polymorphisms in loci that are in DNA repair pathways, are related to non-small-cell lung cancer (NSCLC) and whether they may modulate the association between residential radon exposure and lung cancer in both smokers and never smokers.

METHODS

A multicentre, hospital-based, case-control study with 826 cases and 1201 controls was designed in a radon-prone area. Genotyping was determined in whole blood and residential radon exposure was measured in participants' dwellings.

RESULTS

Attending to tobacco exposure, the variant in the gene NBN (rs1805794) was associated with lung cancer in never smokers (OR 2.72; 95%1.44-5.2) and heavy smokers (OR 3.04; 95%CI 1.21-7.69). The polymorphism with the highest lung cancer association was OGG1 (rs125701), showing an OR of 8.04 (95%CI 1.64-58.29) for its homozygous variant genotype in heavy smokers. Attending to indoor radon exposure (>200Bq/m3), rs1452584, for its homozygous variant genotype, showed the highest association (OR 3.04 (95%CI 1.15-8.48).

CONCLUSION

The genes analyzed seem to have no association with the fully adjusted model, but they might modulate lung cancer association when different categories of tobacco consumption are considered (i.e. heavy smokers). This association may similarly be elevated for those individuals having high indoor radon exposures, though at a minor extent.

Targeting DNA Damage Response and Repair to Enhance Therapeutic Index in Cisplatin-Based Cancer Treatment

Platinum-based chemotherapies, such as cisplatin, play a large role in cancer treatment. The development of resistance and treatment toxicity creates substantial barriers to disease control, yet. To enhance the therapeutic index of cisplatin-based chemotherapy, it is imperative to circumvent resistance and toxicity while optimizing tumor sensitization. One of the primary mechanisms by which cancer cells develop resistance to cisplatin is through upregulation of DNA repair pathways. In this review, we discuss the DNA damage response in the context of cisplatin-induced DNA damage. We describe the proteins involved in the pathways and their roles in resistance development. Common biomarkers for cisplatin resistance and their utilization to improve patient risk stratification and treatment personalization are addressed. Finally, we discuss some of the current treatments and future strategies to circumvent the development of cisplatin resistance.

Genetic evaluation of the variants using MassARRAY in non-small cell lung cancer among North Indians

Lung cancer is genetically diverse and a major health burden. Non-small cell lung cancer (NSCLC) accounts for 80% of total lung cancer cases and 20% cases are Small cell lung cancer (SCLC). The present case–control association study focused on the cost effective high throughput genotyping using Agena MassARRAY matrix-assisted laser desorption/ionization-time of flight, mass spectrometry (MALDI-TOF) platform to analyze the genetic association of candidate genetic variants. We performed multiplex PCR and genotyped twelve single nucleotide polymorphisms (SNPs) in 723 samples (162 NSCLC cases and 592 healthy controls). These genetic variants were selected from literature for their association with various cancers worldwide and this is the first study from the region to examine these critically important genetic variants. With prospective case–control association study design, twelve variants from ten genes were evaluated. Amongst these six variants, TCF21 (rs12190287), ERCC1 (rs2298881, 11615), ERCC5 (rs751402), ARNTL (rs4757151), BRIP1 (rs4986764) showed significant association with NSCLC risk (p ≤ 0.003) in Jammu and Kashmir population. In-silico findings of these genetic variants showed remarkable functional roles that needs in-vitro validations. It is further anticipated that such case control studies will help us in understanding the missing heritability of non-small cell lung cancer.

MassArray analysis of genomic susceptibility variants in ovarian cancer

Ovarian cancer (OC), a multifaceted and genetically heterogeneous malignancy is one of the most common cancers among women. The aim of the study is to unravel the genetic factors associated with OC and the extent of genetic heterogeneity in the populations of Jammu and Kashmir (J&K).Using the high throughput Agena MassARRAY platform, present case control study was designed which comprises 200 histopathological confirmed OC patients and 400 age and ethnicity matched healthy controls to ascertain the association of previously reported eleven single nucleotide polymorphisms (SNPs) spread over ten genes (DNMT3A, PIK3CA, FGFR2, GSTP1, ERCC5, AKT1, CASC16, CYP19A1, BCL2 and ERCC1) within the OC population of Jammu and Kashmir, India. The association of each variant was estimated using logistic regression analyses. Out of the 11 SNPs the odds ratio observed for three SNPs; rs2699887 was (1.72 at 95% CI: 1.19-2.48, p = 0.004), rs1695 was (1.87 at 95% CI: 1.28-2.71, p = 0.001), and rs2298881 was (0.66 at 95% CI: 0.46-0.96, p = 0.03) were found significantly associated with the OC after correction with confounding factors i.e. age & BMI. Furthermore, the estimation of interactive analyses was performed and odds ratio observed was 2.44 (1.72-3.47), p value < 0. 001 suggests that there was a strong existence of interplay between the selected genetic variants in OC, which demonstrate that interactive analysis highlights the role of gene-gene interaction that provides an insight among multiple little effects of various polymorphisms in OC.

Expression and Genetic Polymorphisms of ERCC1 in Chinese Han Patients with Oral Squamous Cell Carcinoma

The aim of this study was to investigate the expression of the excision repair cross-complementation group 1 (ERCC1) in oral squamous cell carcinoma (OSCC) and the possible association of ERCC1 polymorphisms with susceptibility and response to chemotherapy of OSCC in a Chinese Han population. The expression of ERCC1 was determined by real-time PCR in eight patients. Four single-nucleotide polymorphisms (SNPs) rs11615, rs3212948, rs3212961, and rs735482 of ERCC1 were genotyped in 113 OSCC patients and 184 healthy controls using a PCR restriction matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS) assay. We found that a higher gene expression of ERCC1 was observed in tumor tissue as compared to pericarcinomatous tissue in OSCC patients. All genotypic and allelic frequencies of the tested ERCC1 polymorphisms were in Hardy-Weinberg equilibrium. The genotypic and allelic frequencies of rs11615, rs3212948, rs3212961, and rs735482 of ERCC1 were not different between OSCC patients and controls. No correlation was observed between ERCC1 polymorphisms and the response to chemotherapy. Our results show that ERCC1 is increased in the tumor tissue of OSCC patients. The investigated ERCC1 gene polymorphisms (rs11615, rs3212948, rs3212961, and rs735482) are not associated with the susceptibility and response to chemotherapy of OSCC in our investigated Chinese Han population.

Functional FGFR4 Gly388Arg polymorphism contributes to cancer susceptibility: Evidence from meta-analysis

Fibroblast growth factor receptor 4 (FGFR4) is a member of receptor tyrosine kinase family. A functional Gly388Arg (rs351855 G>A) polymorphism in FGFR4 gene causes a glycine-to-arginine change at codon 388 within the transmembrane domain of the receptor. Although the FGFR4 rs351855 G>A polymorphism has been implicated in cancer development, its association with cancer risk remains controversial. Here, we have systematically analyzed the association between the rs351855 G>A polymorphism and cancer risk by performing a meta-analysis of 27 studies consisting of 8,682 cases and 9,731 controls. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to measure the strength of the association. The rs351855 G>A polymorphism was associated with an increased cancer risk under the recessive model (OR=1.19, 95% CI=1.01-1.41). Stratified analysis by cancer type indicated the rs351855 G>A polymorphism was associated with an increased risk of breast and prostate cancer, but a decreased risk of lung cancer. This meta-analysis demonstrates the FGFR rs351855 G>A polymorphism is associated with increased cancer risk and suggests it could potentially serve as a chemotherapeutic target or biomarker to screen high-risk individuals.

ERCC1 as a prognostic factor for survival in patients with advanced urothelial cancer treated with platinum based chemotherapy: A systematic review and meta-analysis

BACKGROUND

The predictive role of excision repair cross-complementing group 1 (ERCC1) as a predictive factor in patients with advanced urothelial cancer (AUC) treated with platinum-based treatment is not well defined. Here, we evaluate the role of ERCC1 in patients with AUC treated with platinum-based treatment.

METHODS

We performed comprehensive, systematic computerized search to identify relevant studies through Medline, Embase, Cochrane Controlled Trials Register (CCTR) databases and abstracts from American Society of Clinical Oncology (ASCO) and ASCO Genitourinary Cancers Symposium, European Society For Medical Oncology (ESMO) and European Association of Urology (EAU) meeting up to July 2015. A systematic review and meta-analysis were performed.

RESULTS

We included a total of 1475 patients from 13 studies. We found that ERCC1 positivity was significantly associated with worse progression-free survival (pooled HR: 1.54, 95% CI: 1.13-2.11, p=0.006). There was no significant association with overall survival (pooled HR1.63, 95% CI: 0.93-2.88, p=0.09) and disease-free survival (pooled HR: 1.092, 95% CI: 0.63-1.90, p=0.75).

CONCLUSION

ERCC1 positivity might be a prognostic indicator for poorer survival outcomes among patients with AUC. ERCC1 positivity was trending to poorer OS but was statistically worse for PFS. Further large prospective studies are warranted as ERCC1 could be used as a predictive marker to direct treatment of patients with AUC.

Genetic biomarkers for hepatocellular cancer risk in a caucasian population

AIM

To uncover novel genetic markers that could contribute to predicting hepatocellular carcinoma (HCC) susceptibility in Caucasians.

METHODS

The present retrospective case-control study compared genotype frequencies between a cohort of HCC cases and two, independent, HCC-free, age/sex-matched control groups. The HCC cohort comprised 192 homogeneous patients that had undergone orthotopic liver transplantation. The first control group comprised 167 patients that were matched to the HCC cohort for the percentage of hepatitis B (HBV) and/or hepatitis C (HCV) infections. A second control group included 192 virus-free, healthy individuals that were used to evaluate the generalizability of the identified predictive markers. All cases and controls were Caucasian. The three study populations were characterized with a panel of 31 markers derived from 21 genes that encoded key proteins involved in hepatocarcinogenesis-related pathways. The study end-point was to assess the association between genetic variants and HCC onset.

RESULTS

Five genetic markers were identified as risk factors for HCC in high-risk patients infected with HBV/HCV. According to a dominant model, reduced HCC risk was associated with three polymorphisms: ERCC1 rs3212986 (OR = 0.46, 95%CI: 0.30-0.71, P = 0.0005), GST-P1 rs1138272 (OR = 0.41, 95%CI: 0.21-0.81, P = 0.0097), and CYP17A1 rs743572 (OR = 0.50, 95%CI: 0.31-0.79, P = 0.0032). Conversely, according to a recessive model, increased HCC risk was associated with two polymorphisms: XRCC3 rs1799794 (OR = 3.70, 95%CI: 1.02-13.39, P = 0.0461) and ABCB1 rs1128503 (OR = 2.06, 95%CI: 1.18-3.61, P = 0.0111). These associations remained significant in a subgroup analysis, where patients were stratified according to viral status (HBV- or HCV-positive serology). Two variants exhibited a serology-specific effect: ABCB1 rs1128503 (OR = 4.18, 95%CI: 1.55-11.29, P = 0.0048) showed an effect in the HBV-positive subgroup; and ERCC1 rs3212986 (OR = 0.33, 95%CI: 0.18-0.60, P = 0.0003) showed an effect in the HCV-positive subgroup. Among the five markers identified, ERCC1 rs3212986 (OR = 0.43, P < 0.0001) and CYP17A1 rs743572 (OR = 0.73, P = 0.0310) had a different distribution in patients with HCC compared to healthy individuals. With a recursive partitioning approach, we also demonstrated that significant gene-gene interactions between ERCC1 rs3212986, CYP17A1 rs743572, GST-P1 rs1138272, and the previously described UGT1A7*3 predictive marker, played a role in the complex trait of HCC susceptibility.

CONCLUSION

We identified five polymorphisms and interactions that contributed crucially to predicting HCC risk. These findings represented an important step towards improving HCC diagnosis and management.

Genetic polymorphisms and lung cancer risk: Evidence from meta-analyses and genome-wide association studies

A growing number of studies investigating the association between Single Nucleotide Polymorphisms (SNPs) and lung cancer risk have been published since over a decade ago. An updated integrative assessment on the credibility and strength of the associations is required. We searched PubMed, Medline, and Web of Science on or before August 29^th, 2016. A total of 198 articles were deemed eligible for inclusion, which addressed the associations between 108 variants and lung cancer. Among the 108 variants, 63 were reported to be significantly associated with lung cancer while the remaining 45 were reported non-significant. Further evaluation integrating the Venice Criteria and false-positive report probability (FPRP) was performed to determine the strength of cumulative epidemiological evidence for the 63 significant associations. As a result, 15 SNPs on or near 12 genes and one miRNA with strong evidence of association with lung cancer risk were identified, including TERT (rs2736098), CHRNA3 (rs1051730), AGPHD1 (rs8034191), CLPTM1L (rs401681 and rs402710), BAT3 (rs3117582), TRNAA (rs4324798), ERCC2 (Lys751Gln), miR-146a2 (rs2910164), CYP1B1 (Arg48Gly), GSTM1 (null/present), SOD2 (C47T), IL-10 (-592C/A and -819C/T), and TP53 (intron 6). 19 SNPs were given moderate rating and 17 SNPs were rated as having weak evidence. In addition, all of the 29 SNPs identified in 12 genome-wide association studies (GWAS) were proved to be noteworthy based on FPRP value. This review summarizes and evaluates the cumulative evidence of genetic polymorphisms and lung cancer risk, which can serve as a general and useful reference for further genetic studies.

Prognostic implication of ERCC1 protein expression in resected oropharynx and oral cavity cancer

BACKGROUND

Excision repair cross complement group 1 (ERCC1) expression is a predictive biomarker for platinum-containing treatment in squamous cell carcinoma of head and neck (SCCHN). However, the prognostic significance after surgical resection is not well understood.

METHODS

Oropharynx (n=143) or oral cavity (n=61) SCCHN patients undergoing surgery were included. ERCC1 protein expression and HPV status were assessed by ERCC1 and p16 immunohistochemistry.

RESULTS

The ERCC1, over-expressed in 66.7% of patients, was associated with oral cavity cancer (P<0.001), well differentiation (P=0.036), and HPV negativity (P<0.001). In TCGA database, ERCC1 mRNA upregulation was enriched in HPV-negative and oral cavity cancers, and associated with HRAS mutation (P<0.001). The prognostic role of ERCC1 was not different according to HPV status. High ERCC1 expression showed a trend toward poor prognosis in patients with an advanced stage (P=0.079) with marginal significance.

CONCLUSIONS

The ERCC1 expression was not prognostic in surgically resected oropharynx/oral cavity SCCHN, irrespective of HPV status. However, it could provide additional prognostic information for advanced stage patients.

CASP8 -652 6N insertion/deletion polymorphism and overall cancer risk: evidence from 49 studies

The CASP8 -652 6N insertion/deletion (I/D) polymorphism reduces expression of caspase 8. We conducted a meta-analysis to clarify the relationship between this polymorphism and cancer risk. Eligible articles were retrieved from PubMed, EMBASE, CNKI, and WANFANG databases through February 2017. A total of 33 articles with 49 studies, including 33,494 cases and 36,397 controls, were analyzed. We found that the CASP8 -652 6N ins/del polymorphism was associated with decreased overall cancer risk in five genetic models [DD vs. II: odds ratio (OR)=0.76, 95% confidence interval (CI)=0.69–0.84, ID vs. II: OR=0.87, 95% CI=0.83–0.92, DD vs. ID/II: OR=0.82, 95% CI=0.75–0.89, ID/DD vs. II: OR=0.85, 95% CI=0.80–0.90, and D vs. I: OR=0.87, 95% CI=0.83–0.91]. Stratified analyses showed that the polymorphism was associated with decreased risk of colorectal, breast, esophageal, renal cell, lung, cervical, bladder, gastric, and other cancers. Overall cancer risk was reduced in Asian and Caucasian patients, both hospital- and population-based studies, and both high and low quality studies. Our results highlight the role of the CASP8 -652 6N ins/del polymorphism in decreasing cancer risk. Further studies with large-cohort populations, especially for specific cancer types and ethnic groups, are needed to confirm our findings.

Biological and predictive role of ERCC1 polymorphisms in cancer

Excision repair cross-complementation group 1 (ERCC1) is a key component in DNA repair mechanisms and may influence the tumor DNA-targeting effect of the chemotherapeutic agent oxaliplatin. Germline ERCC1 polymorphisms may alter the protein expression and published data on their predictive and prognostic value have so far been contradictory. In the present article we review available evidence on the clinical role and utility of ERCC1 polymorphisms and, in the absence of a 'perfect' trial, what we call the 'sliding doors' trial, we present the data of ERCC1 genotyping in our local patient population. We found a useful predictive value for oxaliplatin-induced risk of anemia.

Association of XPC Gene Polymorphisms with Colorectal Cancer Risk in a Southern Chinese Population: A Case-Control Study and Meta-Analysis

Xeroderma pigmentosum group C (XPC) is a key component of the nucleotide excision repair (NER) pathway. Dysfunctional XPC protein may impair NER-mediated DNA repair capacity and further lead to genomic instability and carcinogenesis. Two common nonsynonymous polymorphisms in the XPC gene, Lys939Gln (rs2228001 A > C) and Ala499Val (rs2228000 C > T), have been investigated in various types of cancer. We genotyped these two polymorphisms in 1141 cases with histologically confirmed colorectal cancer (CRC) and 1173 healthy controls to explore their causative association with CRC susceptibility. Overall, no association was observed between these two variants and the risk of CRC. Our meta-analysis also confirmed a lack of overall association. Stratified analyses were performed by age, gender, smoking status, pack-year, drinking status, tumor sites, and Duke's stages. We found that XPC Lys939Gln polymorphism was significantly associated with an increased CRC risk in subjects at 57 years of age or younger (adjusted odds ratio (OR) = 1.37, 95% confidence interval (CI) = 1.004-1.86, p = 0.047) and non-drinkers (adjusted OR = 1.53, 95% CI = 1.10-2.12, p = 0.011). Our results indicated that XPC Lys939Gln may be a low-penetrance CRC susceptibility polymorphism. Our findings warrant further validation.

Functional intronic ERCC1 polymorphism from regulomeDB can predict survival in lung cancer after surgery

We searched for potential regulatory single nucleotide polymorphisms (SNPs) in excision repair cross-complementing group 1 (ERCC1) using RegulomeDB, a database integrating information from the Encyclopedia of DNA Elements (ENCODE) project, and investigated their association with survival after surgery in non-small cell lung cancer (NSCLC). Among 364 SNPs found within ERCC1 region using RegulomeDB, four top priority SNPs (rs2298881C>A, rs1049739A>G, rs10415949A>G and rs6509214G>T) were selected for this study. The four SNPs were investigated in 316 patients. A replication study was performed (n = 579). Of the four SNPs analyzed in the discovery set, rs2298881C>A and rs6509214G>T were significantly associated with survival outcomes. The association was consistently observed only for rs2298881C>A in the validation cohort. In combined analysis, rs2298881C>A was significantly associated with worse overall survival and disease-free survival (P = 0.0002 and 0.02, respectively). A decreased reporter gene expression for rs2298881 A allele was observed compared with C allele by luciferase assay (P = 0.02). ERCC1 rs2298881C>A, an intronic SNP, is the first genetic polymorphism with functional evidence of regulating its expression, and the SNP is associated with prognosis of NSCLC. Our result supports the role of RegulomeDB as a comprehensive source of prioritized candidate SNPs for genetic association studies.

Polymorphisms in the AKT1 and AKT2 genes and oesophageal squamous cell carcinoma risk in an Eastern Chinese population

Ethnic Han Chinese are at high risk of developing oesophageal squamous cell carcinoma (ESCC). Aberrant activation of the AKT signalling pathway is involved in many cancers, including ESCC. Some single nucleotide polymorphisms (SNPs) in genes involved in this pathway may contribute to ESCC susceptibility. We selected five potentially functional SNPs in AKT1 (rs2494750, rs2494752 and rs10138277) and AKT2 (rs7254617 and rs2304186) genes and investigated their associations with ESCC risk in 1117 ESCC cases and 1096 controls in an Eastern Chinese population. None of individual SNPs exhibited an association with ESCC risk. However, the combined analysis of three AKT1 SNPs suggested that individuals carrying one of AKT1 variant genotypes had a decreased ESCC risk [adjusted odds ratio (OR) = 0.60, 95% CI = 0.42-0.87]. Further stratified analysis found that AKT1 rs2294750 SNP was associated with significantly decreased ESCC risk among women (adjusted OR = 0.63, 95% CI = 0.43-0.94) and non-drinkers (OR = 0.79, 95% CI = 0.64-0.99). Similar protective effects on women (adjusted OR = 0.56, 95% CI = 0.37-0.83) and non-drinker (adjusted OR = 0.75, 95% CI = 0.60-0.94) were also observed for the combined genotypes of AKT1 SNPs. Consistently, logistic regression analysis indicated significant gene-gene interactions among three AKT1 SNPs (P < 0.015). A three-AKT1 SNP haplotype (C-A-C) showed a significant association with a decreased ESCC risk (adjusted OR = 0.70, 95% CI = 0.52-0.94). Multifactor dimensionality reduction analysis confirmed a high-order gene-environment interaction in ESCC risk. Overall, we found that three AKT1 SNPs might confer protection against ESCC risk; nevertheless, these effects may be dependent on other risk factors. Our results provided evidence of important gene-environment interplay in ESCC carcinogenesis.

XRCC3 Thr241Met Polymorphism is not Associated with Lung Cancer Risk in a Romanian Population

BACKGROUND AND AIMS

Deoxyribonucleic Acid (DNA) repair mechanisms play a critical role in protecting the cellular genome against carcinogens. X-ray cross-complementing gene 3 (XRCC3) is involved in DNA repair and therefore certain genetic polymorphisms that occur in DNA repair genes may affect the ability to repair DNA defects and may represent a risk factor in carcinogenesis. The purpose of our study was to investigate the association between XRCC3 gene substitution of Threonine with Methionine in codon 241 of XRCC3 gene (Thr241Met) polymorphism and the risk of lung cancer, in a Romanian population.

METHODS

We recruited 93 healthy controls and 85 patients with lung cancer, all smokers. Thr241Met, XRCC3 gene genotyping was determined by multiplex Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP).

RESULTS

Statistical analysis (OR, recessive model), did not revealed an increased risk for lung cancer, for the variant 241Met allele and Thr241Met genotypes (p=0.138, OR=0.634, CI=0.348-1.157; p=0.023, OR=0.257, CI=0.085-6.824). Also, there were no positive statistical associations between Thr241Met polymorphism of XRCC3 gene, gender, tobacco and various histopathological tumor type of lung cancer.

CONCLUSION

In conclusion, the results of the study suggest that the XRCC3 gene Thr241Met polymorphism is not associated with an increased risk for the development of lung cancer in this Romanian group.

Association of single nucleotide polymorphisms of DNA repair genes in NER pathway and susceptibility to pancreatic cancer

In our study, we conducted a case-control study to investigate the association of ERCC1, ERCC2, ERCC3, ERCC4, ERCC5, XPA, XPC and DDB2 gene polymorphisms in the risk of pancreatic cancer. Between May 2012 and May 2014, a total of 246 patients with who were newly diagnosed with histopathologically confirmed primary pancreatic cancer and 246 controls were selected into our study. Genotyping of ERCC1 rs3212986 and rs11615, ERCC2 rs13181, ERCC3 rs4150441, ERCC4 rs6498486, ERCC5 rs873601, XPA rs2808668, XPC rs2228000, XPC rs2228001 and DDB2 rs2029298 were analyzed using polymerase chain reaction (PCR) coupled with restriction fragment length polymorphism (RFLP). By conditional logistic regression analysis, individuals carrying with TT genotype of ERCC1 rs3212986 and GG genotype of ERCC2 rs13181 were associated with increased risk of pancreatic cancer when compared with wide-type genotype, and the adjusted ORs (95% CI) were 2.40 (1.29-4.52) and 2.27 (1.26-4.15), respectively. We found that individuals carrying with GT+TT genotype of ERCC1 rs3212986 and TG+GG genotype of ERCC2 rs1318 gene polymorphisms were correlated with higher risk of pancreatic cancer in smokers when compared with non-smokers, and the adjusted ORs (95% CI) were 1.89 (1.05-3.40) and 1.88 (1.06-3.34), respectively. In conclusion, our study suggests that ERCC1 rs3212986 and ERCC2 rs1318 gene polymorphisms contribute to the development of pancreatic cancer, especially in smokers.

Screening for lung cancer using low-dose computed tomography: concerns about the application in low-risk individuals

Low-dose computed tomography (LDCT) has been increasingly accepted as an efficient screening method for high-risk individuals to reduce lung cancer mortality. However, there remains a gap of knowledge in the practical implementation of screening on a larger scale, especially for low-risk individuals. The aim of this study is to initiate discussion through an evidence-based analysis and provide valuable suggestions on LDCT screening for lung cancer in clinical practice. Among previously published randomized controlled trials (RCTs), the National Lung Screening Trial (NLST) is the only one demonstrating positive results in a high-risk population of old age and heavy smokers. It is also shown that the potential harms include false-positive findings, radiation exposure etc., but its magnitude is uncertain. In the meantime, the current risk stratification system is inadequate, and is difficult to define selection criteria. Thus, the efficacy of LDCT in lung cancer screening needs to be confirmed in future trials, and the procedure should not be proposed to individuals without comparable risk to those in the NLST. Furthermore, there is a lack of evidence to support the expansion of LDCT screening to low-risk individuals. Therefore, recommendation of LDCT screening for these patients could be premature in clinical practice although some of them might be missed based on current definition of risk factors. Further studies and advances in risk assessment tools are urgently needed to address the concerns about lung cancer screening in order to improve the outcomes of lung cancer.

Association of ERCC1 polymorphisms (rs3212986 and rs11615) with the risk of head and neck carcinomas based on case-control studies

PURPOSE

Current data regarding association between ERCC1 polymorphisms and the risk of head and neck squamous cell carcinomas (HNSCC) have shown controversial results. The current study aims to achieve a more accurate estimation of the association between two well-characterized ERCC1 polymorphisms (rs3212986 and rs11615) and HNSCC risk by a meta-analysis of all eligible studies.

METHODS

The meta-analysis was performed by reviewing seven studies on the ERCC1 C8092A (rs3212986) polymorphism including 2055 cases and 2635 controls and four studies on the T19007C (rs11615) polymorphism including 910 cases and 1337 controls.

RESULTS

For ERCC1 rs3212986 polymorphism, no significant association with HNSCC was found in overall analysis, but subgroup analysis revealed that a significant association of the rs3212986 polymorphism was found among Asians (A vs. C: OR 0.83; 95% CI 0.70-0.99) but not Caucasians. For ERCC1 rs11615 polymorphism, a significant association with HNSCC (TC + CC vs. TT: OR 1.23; 95% CI 1.03-1.47) was found in overall analysis. Consistently, subgroup analysis revealed that significant associations of the rs3212986 polymorphism were found among Asians (C vs. T: OR 1.32; 95% CI 1.04-1.69) and in laryngeal carcinoma (CC vs. TC + TT: OR 1.32; 95% CI 1.02-1.72).

CONCLUSION

The findings of the meta-analysis indicated that a decreased risk for the ERCC1 rs3212986 polymorphism was found among Asians, and an increased risk for the ERCC1 rs11615 polymorphism was found in overall HNSCC, especially in Asian subgroup and laryngeal site, suggesting that ERCC1 rs3212986 polymorphism in Asians may act as a protective factor and rs11615 polymorphism may be a risk factor for HNSCC.

Associations of PI3KR1 and mTOR polymorphisms with esophageal squamous cell carcinoma risk and gene-environment interactions in Eastern Chinese populations

Single nucleotide polymorphisms (SNPs) in the PI3K/PTEN/AKT/mTOR signaling pathway may contribute to carcinogenesis. We genotyped five potentially functional PIK3R1 and mTOR SNPs in 1116 esophageal squamous cell cancer (ESCC) patients and 1117 cancer-free controls to assess their associations with ESCC risk. We observed no association with ESCC risk for any of the selected SNPs. However, the combined analysis of these SNPs revealed that subjects with one-to-three risk genotypes had an increased ESCC risk. Stratified analysis by body mass index (BMI) found that ESCC risk was significantly associated with each of three mTOR SNPs among subjects with BMI < 25.0. Specifically, we found that subjects carrying ≥ 1 risk genotypes had significantly increased ESCC risk, particularly for males, ever-smokers, ever-drinkers, and those with age > 60, or BMI < 25.0. Moreover, three mTOR haplotypes were associated with an increase in ESCC risk. Our meta-analysis of mTOR rs2295080 and cancer risk provided further evidence that mTOR SNPs might modulate cancer susceptibility. In this population, such risk effects might be modified by other risk factors, highlighting the importance of gene-environment interaction in esophageal carcinogenesis. Additional, larger studies are warranted to validate our findings.