Modulation of Colorectal Cancer Risk by Polymorphisms in 51Gln/His, 64Ile/Val, and 148Asp/Glu of APEX Gene; 23Gly/Ala of XPA Gene; and 689Ser/Arg of ERCC4 Gene. Gastroenterol Res Pract. 2017;2017:3840243. [PMID: 28386271 PMCID: PMC5366231 DOI: 10.1155/2017/3840243]

Polymorphisms of nucleotide excision repair genes associated with colorectal cancer risk: Meta-analysis and trial sequential analysis

Background: Reduced DNA repair capacity in nucleotide excision repair (NER) pathways owing to genetic variant may influence cancer susceptibility. According to published studies, variants of NER genes associations with colorectal cancer (CRC) risk were inconclusive. Thus, this meta-analysis aimed to explore the possible association. A trial sequence analysis (TSA) analysis was performed to control the risk of false positive or false negative.

Methods: PubMed, Web of Science, Embase, Cochrane Library, China National Knowledge Network (CNKI), Wanfang Database and Scientific and Technical Journal Database (VIP) were searched to identify relative studies until April 2022. The association was assessed by odds ratio (OR) in Allele, homozygous, heterozygous, dominant, recessive, and over-dominant models. In addition, Begg’s and Egger’s tests, sensitivity analysis, subgroup analysis and TSA analysis were performed.

Results: A total of 29 studies were eventually included in the meta-analysis, including 12,153 CRC patients and 14,168 controls. It showed that excision and repair cross complementary group 1 (ERCC1) rs11615 CC genotype decreased the risk of CRC, compared with TT genotype (CC vs. TT: OR = 0.816, 95% CI = 0.673–0.990, p = 0.039). For ERCC1 rs3212986, the significant impact was detected on increased the risk of CRC in the allele (OR = 1.267, 95% CI = 1.027–1.562, p = 0.027), homozygous (OR = 1.805, 95% CI = 1.276–2.553, p = 0.001), dominant (OR = 1.214, 95% CI = 1.012–1.455, p = 0.037) and recessive (OR = 1.714, 95% CI = 1.225–2.399, p = 0.002) models, especially in the Asian population. The results revealed the association of ERCC2 rs1799793 A allele with a higher risk of CRC (A vs. G: OR = 1.163, 95% CI = 1.021–1.325, p = 0.023). It also showed that ERCC5 rs17655 increased CRC risk in the allele (OR = 1.104, 95% CI = 1.039–1.173, p = 0.001), homozygous (OR = 1.164, 95% CI = 1.018–1.329, p = 0.026), heterozygous (OR = 1.271, 95% CI = 1.018–1.329, p < 0.001), dominant (OR = 1.241, 95% CI = 1.135–1.358, p < 0.001) and over-dominant (OR = 0.828, 95% CI = 0.762–0.900, p < 0.001) models, especially among Asians.

Conclusion: This meta-analysis based on current evidence suggests that the significant association was observed between ERCC1 rs11615, ERCC1 rs3212986, ERCC2 rs1799793, and ERCC5 rs17655 and CRC susceptibility. However, given the limited sample size and the influence of genetic background, studies of a larger scale and well-designed are required to confirm the results.

Contribution of XPD and XPF Polymorphisms to Susceptibility of Non-Small Cell Lung Cancer in High-Altitude Areas

BACKGROUND

We aimed to explore the relation of XPD and XPF variants with non-small cell lung cancer (NSCLC) risk and the effect of these variants on the sensitivity to cisplatin-based chemotherapy among the Chinese Han population in high-altitude areas.

METHODS

Eight single-nucleotide polymorphisms (SNPs) in XPD and XPF were genotyped by Agena MassARRAY platform among 506 NSCLC cases and 510 healthy controls. Correlation of XPD and XPF gene polymorphisms with NSCLC susceptibility and the response of cis-platin-based chemotherapy were analyzed with logistic regression by calculating odds ratios (ORs) and 95% confidence intervals (CIs).

RESULTS

XPD rs13181 (OR = 1.53, 95% CI: 1.04-2.24, p = 0.029) and rs1052555 (OR = 1.63, 95% CI: 1.05-2.53, p = 0.029) possibly contributed to the increased risk of lung adenocarcinoma, while XPD rs238406 (OR = 0.63, 95% CI: 0.43-0.94, p = 0.024) was a protective factor for lung squamous cell carcinoma. Age, gender, BMI, smoking, and drinking might affect the correlation of XPD and XPF polymorphisms with NSCLC risk. More importantly, XPD rs13181 (OR = 2.91, p = 0.015), XPD rs1052555 (OR = 2.67, p = 0.022), and XPF rs231127 (OR = 4.15, p = 0.008) were associated with treatment response in NSCLC patients underwent cisplatin-based chemotherapy.

CONCLUSION

This study found that XPD and XPF variants might contribute to NSCLC risk and the response of cisplatin-based chemotherapy among the Chinese Han population in high-altitude areas.

A Dual Face of APE1 in the Maintenance of Genetic Stability in Monocytes: An Overview of the Current Status and Future Perspectives

Monocytes, which play a crucial role in the immune system, are characterized by an enormous sensitivity to oxidative stress. As they lack four key proteins responsible for DNA damage response (DDR) pathways, they are especially prone to reactive oxygen species (ROS) exposure leading to oxidative DNA lesions and, consequently, ROS-driven apoptosis. Although such a phenomenon is of important biological significance in the regulation of monocyte/macrophage/dendritic cells’ balance, it also a challenge for monocytic mechanisms that have to provide and maintain genetic stability of its own DNA. Interestingly, apurinic/apyrimidinic endonuclease 1 (APE1), which is one of the key proteins in two DDR mechanisms, base excision repair (BER) and non-homologous end joining (NHEJ) pathways, operates in monocytic cells, although both BER and NHEJ are impaired in these cells. Thus, on the one hand, APE1 endonucleolytic activity leads to enhanced levels of both single- and double-strand DNA breaks (SSDs and DSBs, respectively) in monocytic DNA that remain unrepaired because of the impaired BER and NHEJ. On the other hand, there is some experimental evidence suggesting that APE1 is a crucial player in monocytic genome maintenance and stability through different molecular mechanisms, including induction of cytoprotective and antioxidant genes. Here, the dual face of APE1 is discussed.

Nucleotide excision repair pathway gene polymorphisms are associated with risk and prognosis of colorectal cancer

BACKGROUND

Single nucleotide polymorphisms (SNPs) are universally present in nucleotide excision repair (NER) pathway genes, which could make impacts on colorectal carcinogenesis and prognosis.

AIM

To explore the association of all tagSNPs in NER pathway genes with colorectal cancer (CRC) risk and prognosis in a northern Chinese population by a two-stage case-control design composed of a discovery and validation stage.

METHODS

Genotyping for NER SNPs was performed using kompetitive allele specific PCR. In the discovery stage, 39 tagSNPs in eight genes were genotyped in 368 subjects, including 184 CRC cases and 184 individual-matched controls. In the validation stage, 13 SNPs in six genes were analyzed in a total of 1712 subjects, including 854 CRC cases and 858 CRC-free controls.

RESULTS

Two SNPs (XPA rs10817938 and XPC rs2607775) were associated with an increased CRC risk in overall and stratification analyses. Significant cumulative and interaction effects were also demonstrated in the studied SNPs on CRC risk. Another two SNPs (ERCC2 rs1052555 and ERCC5 rs2228959) were newly found to be associated with a poor overall survival of CRC patients.

CONCLUSION

Our findings suggest novel SNPs in NER pathway genes that can be predictive for CRC risk and prognosis in a large-scale Chinese population. The present study has referential values for the identification of all-round NER-based genetic biomarkers in predicting the susceptibility and clinical outcome of CRC.

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.

XPA gene polymorphisms and risk of neuroblastoma in Chinese children: a two-center case-control study

Neuroblastoma is a malignant tumor arising from the developing sympathetic nervous system, which mainly affects children. Variations in XPA gene have been shown to confer cancer susceptibility. However, no investigation has been reported regarding the association between XPA polymorphisms and neuroblastoma risk. This study was conducted to measure the association of XPA polymorphisms with neuroblastoma susceptibility in Chinese children. In this hospital-based case-control study with 393 cases and 812 controls, we genotyped two polymorphisms (rs1800975 T>C, and rs3176752 G>T) in XPA gene to access their contributions to neuroblastoma risk by TaqMan methods. The strength of the association with neuroblastoma risk was estimated by odds ratios (ORs) and 95% confidence intervals (CIs). No single polymorphism was found to predispose to neuroblastoma susceptibility. When risk genotypes were combined, we found that carriers of 1-2 risk genotypes had significantly increased neuroblastoma risk (adjusted OR=1.28; 95% CI=1.001-1.64, P=0.049), when compared to non-carriers. Stratification analysis by age, gender, sites of origin and clinical stages failed to show any significant association. Our study provides cues that XPA gene polymorphisms may exert a weak effect in neuroblastoma risk. This finding needs further validations by larger sample size studies.