Relationship between XPD Lys 751 Gln polymorphism and colorectal cancer risk: a case-control study in a population-based study

AIM In our study, we analyzed the allelic frequency of XPD Lys751Gln polymorphism of the XPD gene and the correlation between its variant alleles with colorectal cancer in patients and control groups. BACKGROUND Human cells are routinely exposed to mutagenic and carcinogenic aromatic amines via smoking, pollution areas and other sources. These chemicals can form DNA adducts in vivo and thus lead to DNA damage. Amongst the known genetic polymorphisms of the DNA-repair genes the xeroderma pigmentosum group D (XPD, also known as ERCC2) has been the most extensively studied most commonly. PATIENTS AND METHODS This study has examined the relationship between the XPD Lys 751 Gln polymorphism and colorectal cancer in 88 patients and their 88 age and sex-matched controls. Genomic DNA from peripheral whole blood was extracted using Miller method to determine the genotype of subjects with RFLP-PCR analysis. RESULTS This study shows cancer patients have more of the heterozygous genotype (XPD Lys 751 Gln) compared to control group. However the results are not statistically significant. Furthermore, colorectal cancer was less common in individuals with recessive homozygous genotype (P< 0.0001). CONCLUSION This study suggests that individuals with heterozygous polymorphism (Lys/Gln) may have an increased susceptibility to colorectal cancer compared to other polymorphisms (Lys/Lys and Gln/Gln).