Polymorphisms in P21 (CODON 31) and P53 (CODON 72) : association with breast cancer susceptibility in the Turkish and Greek populations

The aim of this study was to investigate the potential association of p53 codon 72 and/or p21 codon 31 polymorphisms with increased susceptibility for breast cancer either independently or combined in the Turkish and Greek populations. A case-control study was conducted for both populations and the genotypes of the subjects were determined by PCR-RFLP (Turkish; p53 genotypes for 274 cases and 221 controls, p21 genotypes for 322 cases and 246 controls, Greek; p53 genotypes for 138 cases and 138 controls, p21 genotypes for 156 cases and 136 controls were obtained). Binary logistic regression was used to analyze the data. Although the Greek study population alone did not give statistically significant results, the p53 codon 72 Arg/Arg inheritance was found to be significantly associated with breast cancer susceptibility in the Turkish study population (OR=2.16; 95% CI=1.08-4.31) as well as in the combined population of Turkish and Greek subjects (OR=2.35; 95% CI=1.25-4.41). This association was further increased with increased BMI (OR=3.86; 95% CI=1.12-13.26) in the Turkish population but the result should be treated with caution because of the wide confidence interval. The inheritance of the combined p21 codon 31 Arg/Arg or Ser/Arg genotypes increased breast cancer susceptibility in the Turkish study population (OR=1.15; 95% CI=0.75-1.76) although the result is not statistically significant. The most prominent result of this study is that there is an interaction between the p53 Arg72Arg and p21 Arg31Arg or Ser31Arg genotypes for breast cancer susceptibility (OR=2.66; 95% CI=1.06- 6.66). These results let us to conclude that there is a strong association between the p53 Arg72Arg genotype and breast cancer risk in the Turkish population and that the combination of high-risk allelic variants of both p53 and its downstream effector protein p21 may have a role as a risk factor for breast cancer development.