Polymorphisms in DNA repair genes in gastrointestinal stromal tumours: susceptibility and correlation with tumour characteristics and clinical outcome.

ABSTRACT

DNA repair pathways play an essential role in cancer susceptibility by maintaining genomic integrity. This led us to investigate the influence of polymorphisms in the genes coding repair pathway enzymes on gastrointestinal stromal tumours (GIST) susceptibility, tumour characteristics and clinical outcome. We investigated a panel of 20 polymorphisms in 11 genes in 81 cases and 147 controls. The XPD rs13181 wild-type allele and hOGG1 rs1052133 and XPF rs1800067 minor alleles were significantly associated with disease susceptibility. XPA rs1800975 and rs2808668 were associated with tumour size (P = 0.018), metastatic status at onset (P = 0.035) and mitotic index (P = 0.002). With regards to outcome treatment, the XPD rs50872 minor allele had a significant favourable impact on time to progression (TTP). Similarly, the XPC rs2228000 minor allele was correlated with a longer TTP (P = 0.03). On the contrary, the XPC rs2228001 and hOGG1 rs1052133 minor alleles were associated with a diminished TTP (P = 0.005 and P = 0.01, respectively). Regarding OS, we found the presence of at least one hOGG1 (rs1052133) minor allele that had a 60 % lower risk to die compared to the wild-type carriers (P = 0.04). Furthermore, the XRCC3 rs861539 variant allele is associated with a hazard of early death compared with the wild-type genotype (P = 0.04). To the best of our knowledge, this is the first study on polymorphisms in DNA repair genes, belonging to the different pathways, extensively evaluated in GIST patients. Through this multiple candidate gene approach, we report for the first time the significant associations between polymorphisms in DNA repair genes, susceptibility, clinical pathological features and clinical outcome in GIST.