Genetic Association between ERCC5 rs17655 Polymorphism and Colorectal Cancer Risk: Evidence Based on a Meta-analysis

Evaluating the predictive value of genetic risk score in colorectal cancer among Chinese Han population

Increasing single nucleotide polymorphisms (SNPs) have been identified to be associated with colorectal cancer (CRC). We aimed to investigate whether genetic risk scores (GRS) that aggregate information from multiple genetic variants can predict the risk of CRC in a Chinese population. Fifty candidate SNPs were selected to explore the associations with CRC in a discovery sample with 1002 CRC cases and 999 healthy controls. We modeled the significant SNPs identified by the case-control study as a multilocus weighted GRS and estimated the association of GRS with CRC. Furthermore, 300 pairs of cases and controls were included as a validation sample to confirm the finding. Area under the receiver operating characteristic curve (AUROC) was used to evaluate the predictive power of GRS in CRC. A total of seven SNPs were found to increase the risk of CRC, and two SNPs were found to be negatively associated with CRC in the discovery sample. Relative to participants with the lowest quartile of GRS, those with the highest quartile had a 2.64-fold (95% CI: 1.99-3.51) higher risk for CRC. For every 0.1 point of GRS increase, the risk of CRC increase by 11% (95% CI: 8-14%). AUROC for GRS alone were 0.59 (95% CI: 0.57-0.62) and 0.52 (95% CI: 0.46-0.58) in the discovery and validation sample, respectively. AUROC increased to 0.62 (95% CI: 0.59-0.64) and 0.71 (95% CI: 0.65-0.76) by combining environmental risk factors. Our findings support an association between GRS and risk of CRC, which provides evidence of improved prediction model for CRC in China.

Association between nucleotide excision repair gene polymorphism and colorectal cancer risk

BACKGROUND

The nucleotide excision repair system removes a wide variety of DNA lesions from the human genome, and plays an important role in maintaining genomic stability. Single nucleotide polymorphisms (SNPs) in nucleotide excision repair are associated with the various forms of tumor susceptibility. However, the relationship between NER polymorphism and colorectal cancer is not clear.

METHODS

In this study, three candidate SNPs including ERCC4 (rs6498486), ERCC1 (rs3212986), and ERCC5 (rs17655) were analyzed in 1101colorectal cancer patients and 1175 healthy control patients from Jiangsu province (China). Then, we performed Immunohistochemistry, qPCR, and luciferase assay to determine the potential mechanisms.

RESULTS

The ERCC4 rs6498486 AC/CC genotypes show lower susceptibility to CRC than those carrying rs6498486 AA (Adjusted OR = 0.82, 95% CI = 0.69-0.97). However, we did not observe any association between the colorectal cancer risk and the rs3212986(ERCC1) and rs17655(ERCC5) polymorphisms. Immunohistochemistry, qPCR, and luciferase assay revealed that rs6498486 A > C polymorphism in the ERCC4 promoter region could lessen the expression level of ERCC4 by impacting the binding ability of the transcription factor NF-kB, thereby affecting the transcription activity of the ERCC4 gene and decreased ERCC4 gene expression.

CONCLUSION

In brief, our finding demonstrated that ERCC4 rs6498486 serves as a potential biomarker of CRC susceptibility for the development of colorectal cancer.

The association between XPG polymorphisms and cancer susceptibility: Evidence from observational studies

BACKGROUND

Exposure to environmental carcinogens can cause damages to DNA. If not properly repaired, the DNA damages may increase the risk of carcinogenesis. Xeroderma pigmentosum group G (XPG) gene is an essential gene in the nucleotide excision repair (NER) pathway. The association between XPG polymorphisms and cancer susceptibility has been the focus of attention in the molecular epidemiology of cancer. However, the conclusions have been divergent. Therefore, we conducted a comprehensive meta-analysis to precisely evaluate the association of 3 frequently investigated XPG polymorphisms (rs751402, rs873601, and rs2296147) with cancer risk.

METHODS

Pubmed, EMBASE, and Chinese National Knowledge Infrastructure (CNKI) were searched for relevant studies in English and Chinese. Odds ratio (OR) and 95% confidence interval (CI) were used to assess the association between XPG polymorphisms (rs751402, rs873601, and rs2296147) and cancer risk.

RESULTS

Twenty-three studies were included. Overall, there was no significant association between rs751402 polymorphism and overall cancer risk under the 5 gene models. However, we observed strong correlation between rs751402 polymorphism and gastric cancer (C vs T: OR=1.21, 95% CI = 1.00-1.26, P = .045; TC vs CC: OR = 1.12, 95% CI = 1.00-1.24, P = .041; TC/TT vs CC: OR = 1.13, 95% CI = 1.02-1.26, P = .020). There was a significant correlation between rs873601 polymorphism and cancer risk under the homozygous model (GG vs AA: OR = 1.16, 95% CI = 1.07-1.26, P = .001). Moreover, significant association with breast cancer was detected for rs873601 polymorphism under the allele contrast model (G vs A: OR = 1.10, 95% CI = 1.02-1.20, P = .021). In the subgroup of Asian, rs873601 polymorphism was related to the susceptibility to cancer (G vs A: OR = 1.07, 95% CI = 1.03-1.12, P = .010; GG vs AA: OR = 1.15, 95% CI = 1.06-1.26, P = .001; AG/AA vs GG: OR = 1.08, 95% CI = 1.01-1.15, P = .031; AA vs AG/GG: OR = 1.13, 95% CI = 1.05-1.21, P = .001). Significant association between rs2296147 polymorphism and cancer risk were observed in Asian population (CT vs TT: OR = 0.93, 95% CI = 0.87-0.99, P = .036).

CONCLUSIONS

Our meta-analysis suggested that the rs873601 polymorphism was significantly associated with overall cancer risk. The moderate effects of rs751402 and rs2296147 polymorphism on cancer susceptibility might be highly dependent on cancer type and ethnicity, respectively. Large studies are needed to validate our findings, especially in Caucasian and African population.

Association of interleukin-22 polymorphisms with the colon cancer: A case-control study

INTRODUCTION

Interleukin-22 (IL-22), an IL-10 family cytokine produced by T cells and innate lymphoid cells, is implicated in inflammation and tumorigenesis. In this study, we aimed to investigate the association of IL-22 polymorphisms with the colon cancer in a Chinese population.

MATERIALS AND METHODS

Five hundred forty colon cancer cases and 540 healthy controls were recruited in the case-control study. The fluorogenic 5' exonuclease assays were used for genotype analysis of three common polymorphisms (-429C/T, +1046T/A and +1995A/C) of the IL-22 gene.

RESULTS

Colon cancer cases had a significantly higher frequency of IL-22-429 TT genotype [odds ratio (OR)=1.69, 95% confidence interval (CI)=1.24, 2.30; P=0.001] and -429T allele (OR=1.35, 95% CI=1.14, 1.60; P=0.001) than healthy controls. The findings are still emphatic by the Bonferroni correction (P<0.017). When stratifying by the differentiation of colon cancer, we found that colon cancer cases with poor differentiation had a significantly higher frequency of IL-22-429 TT genotype (OR=1.45, 95% CI=1.02, 2.07; P=0.04). When stratifying by the tumor location, tumor size, growth pattern and TNM stage of colon cancer, we found no statistical association. The IL-22 +1046T/A and IL-22 +1995A/C gene polymorphisms were not associated with colon cancer.

CONCLUSION

Our findings suggested that the IL-22 -429C/T gene polymorphisms might be associated with colon cancer.

XPG Asp1104His, XRCC2 Rs3218536 A/G and RAD51 135G/C Gene Polymorphisms and Colorectal Cancer Risk: A Meta-Analysis

Background:

DNA repair mechanisms are crucial for sustaining DNA integrity and preventing carcinogenesis. The xeroderma pigmentosum group G (XPG), X-ray repair cross complementing group 2 (XRCC2) and RAD51 are candidate genes for DNA repair pathways.

Methods:

We performed a meta-analysis of 26 studies that assessed the impact of XPG Asp1104His, XRCC2 rs3218536 A/G and RAD51 135G/C polymorphisms on colorectal cancer (CRC) risk. This study included 10288 CRC patients and 11885 controls, and odds ratio (OR) with its 95% confidence interval (CI) were used to calculate the strength of association.

Results:

The results of overall meta-analysis suggested an association between the XPG Asp1104His polymorphism and CRC susceptibility in allele (OR=1.06; 95% CI=1.01-1.12) and heterozygote model (OR=1.16; 95%CI=1.02-1.31). In the subgroup analysis based on ethnicity and source of control, we found significantly increased CRC cancer risk in Asians (OR=1.12, 95%CI=1.04-1.21) and in hospital-based (OR=1.22, 95%CI=1.08-1.38) populations. Moreover, the RAD51 135 G/C polymorphism increased the risk of CRC in total using allele (OR=1.21) and recessive models (OR=1.62). However, XRCC2 rs3218536 A/G was not associated with the risk of CRC in total or in subgroups.

Conclusions:

According to the results of our meta-analysis, the XPG Asp1104His and RAD51 135 G/C polymorphisms might influence colorectal cancer risk.

The Association of Low-Penetrance Variants in DNA Repair Genes with Colorectal Cancer: A Systematic Review and Meta-Analysis

Objectives:

Approximately 35% of colorectal cancer (CRC) risk is attributable to heritable factors known hereditary syndromes, accounting for 6%. The remainder may be due to lower penetrance polymorphisms particularly of DNA repair genes. DNA repair pathways, including base excision repair (BER), nucleotide excision repair (NER), mismatch repair (MMR), direct reversal repair (DRR), and double-strand break repair are complex, evolutionarily conserved, and critical in carcinogenesis. Germline mutations in these genes are associated with high-penetrance CRC syndromes such as Lynch syndrome. However, the association of low-penetrance polymorphisms of DNA repair genes with CRC risk remains unclear.

Methods:

A systematic literature review of PubMed, Embase, and HuGENet databases was conducted. Pre-specified criteria determined study inclusion/exclusion. Per-allele, pooled odds ratios disclosed the risk attributed to each variant. Heterogeneity was investigated by subgroup analyses for ethnicity and tumor location; funnel plots and Egger’s test assessed publication bias.

Results:

Sixty-one polymorphisms in 26 different DNA repair genes were identified. Meta-analyses for 22 polymorphisms in 17 genes revealed that six polymorphisms were significantly associated with CRC risk within BER (APE1, PARP1), NER (ERCC5, XPC), double-strand break (RAD18), and DRR (MGMT), but none within MMR. Subgroup analyses revealed significant association of OGG1 rs1052133 with rectal cancer risk. Egger’s test revealed no publication bias.

Conclusions:

Low-penetrance polymorphisms in DNA repair genes alter susceptibility to CRC. Future studies should therefore analyze whole-genome polymorphisms and any synergistic effects on CRC risk.

Translational impact:

This knowledge may enhance CRC risk assessment and facilitate a more personalized approach to cancer prevention.