[TP53 gene polymorphisms and colorectal cancer risk in Chinese population]

To investigate the association between the single nucleotide polymorphisms (SNPs) in TP53 gene and susceptibility to colorectal cancer (CRC) in Chinese population.

Peripheral blood samples were collected and white cell genomic DNA was extracted from 345 CRC patients, 198 males and 1447 females, aged (58.7 +/- 13.5), and 670 sex, age, smoking and drinking situations-matched controls in Ningbo city, Zhejiang province The genotypes of the SNPs of C-8343G, C-1863T, and R72P in TP53 gene were determined by either TaqMan assays or PCR-based restriction fragment length polymorphism method. Unconditional logistic regression was used to calculate the odds ratio (OR) for CRC after adjustment of the covariates, such as sex, age, cigarette smoking, alcohol drinking, body mass index and first-degree family history of CRC, and 95% confidence intervals (CI) so as to evaluate relative risk.

There were not significant differences in the above mentioned covariates between these 2 groups. No significant association of C-8343G or C-1863T polymorphism with CRC risk was observed (both P > 0.05). The CRC risk of the 72P genotype was 50.3%, 1.53 times that of the 72R genotype (39.6%) (95% CI = 1.27 - 1.85, P < 0.01). The CRC risk of the RP heterozygotes was 1.60 times that of the RP homozygote (95% CI = 1.17 - 2.18, P < 0.01), and the CRC risk of the PP homozygotes was 2.37 times that of the RP heterozygotes (95% CI = 1.61 - 3.47, P < 0.01). A dose-response relationship was shown (P < 0.01). Stratified analysis indicated that the 72P allele conferred a more pronounced increase in CRC risk among the alcohol consumers: the CRC risk was 3.01 times for the RP heterozygotes (95% CI = 1.48 - 6.12), and 4.71 times for the PP homozygotes (95% CI = 1.90 - 11.68).

TP53 C-8343G and C-1863T polymorphisms are not associated with CRC risk. R72P polymorphism contributes to the etiology of CRC in the Chinese population, particularly among the alcohol consumers.