DNA Repair Gene Polymorphisms in Relation to Non-Small Cell Lung Cancer Survival
CELLULAR PHYSIOLOGY AND BIOCHEMISTRY
Authors: Su, Yuliang; Zhang, Huan; Xu, Fangxiu; Kong, Jinyu; Yu, Herbert; Qian, Biyun
Abstract
Background: Single nucleotide polymorphisms (SNPs) in the DNA repair genes are suspected to be related to the survival of lung cancer patients due to their possible influence on DNA repair capacity (DRC). However, the study results are inconsistent. Methods: A follow-up study of 610 non-small cell lung cancer (NSCLC) patients was conducted to investigate genetic polymorphisms associated with the DNA repair genes in relation to NSCLC survival; 6 SNPs were genotyped, including XRCC1 (rs25487 G>A), hOGG1 (rs1052133 C>G), MUTYH (rs3219489 G>C), XPA (rs1800975 G>A), ERCC2 (rs1799793 G>A) and XRCC3 (rs861539 C>T). Kaplan-Meier survival curve and Cox proportional hazards regression analyses were performed. SNPSNP interaction was also examined using the survival tree analysis. Results: Advanced disease stage and older age at diagnosis were associated with poor prognosis of NSCLC. Patients with the variant 'G' allele of hOGG1 rs1052133 had poor overall survival compared with those with the homozygous wild 'CC' genotype, especially in female patients, adenocarcinoma histology, early stage, light smokers and without family history of cancer. For never smoking female lung cancer patients, individuals carrying homozygous variant 'AA' genotype of XPA had shorter survival time compared to those with wild 'G' alleles. Furthermore, females carrying homozygous variant XPA and hOGG1 genotypes simultaneously had 2.78-fold increased risk for death. Among all 6 polymorphisms, the homozygous variant 'AA' of XPA carriers had poor prognosis compared to the carriers of wild 'G' alleles of XPA together with other base excision repair (BER) polymorphisms. Conclusions: Besides disease stage and age, the study found DNA repair gene polymorphisms were associated with lung cancer survival. Copyright (C) 2015 S. Karger AG, Basel
Is there evidence of involvement of DNA repair polymorphisms in human cancer?
MUTATION RESEARCH-FUNDAMENTAL AND MOLECULAR MECHANISMS OF MUTAGENESIS
Authors: Ricceri, Fulvio; Matullo, Giuseppe; Vineis, Paolo
Abstract
DNA suffers from a wide range of damage, both from extracellular agents and via endogenous mechanisms. Damage of DNA can lead to cancer and other diseases. Therefore, it is plausible that sequence variants in DNA repair genes are involved in cancer development. A recent systematic review and meta-analysis, based on the "Venice criteria", showed that out of 241 associations investigated, only three resulted to have a strong grade of cumulative evidence. These associations were: two SNPs rs1799793 and rs13181 in the ERCC2 gene and lung cancer (recessive model) and rs1805794 in the NBN gene and bladder cancer (dominant model). An update of this meta-analysis has been performed in the present paper, and we found partially inconsistent results. Inconsistencies in the literature are thus far not easy to explain. In addition, none of the cancer genome-wide association studies (GWAs) published so far showed highly statistically significant associations for any of the common DNA repair gene variants, in such a way as to place DNA repair genes among the top 10-20 hits identified in GWAs. Though this suggests that it is unlikely that DNA repair gene polymorphisms per se play a major role, a clarification of the discrepancies in the literature is needed. Also, gene/environment and gene/lifestyle interactions for the carcinogenic mechanisms involving DNA repair should be investigated more systematically and with less classification error. Finally, the combined effect of multiple SNPs in several genes in one or more relevant DNA repair pathways could have a greater impact on pathological phenotypes than SNPs in single genes, but this has been investigated only occasionally. (C) 2011 Elsevier B.V. All rights reserved.