P53 codon 72 polymorphism in Taiwanese breast cancer patients

Abstract

There are clear discrepancies between ethnicity and geographic area regarding the peak age incidence and mortality of breast cancer. Underlying variances include genetic, environmental, and socioeconomic factors. The wild-type p53 codon has two common polymorphic variants from a single-base-pair substitution at codon 72, where either C-C-C encodes proline (p53-p72) or C-G-C encodes arginine (p53-R72). We aim to study the p53 codon 72 genotypes of patients with breast cancer in Taiwan and make a comparison with the published data to ascertain whether any difference exists between Taiwanese and Western patients with breast cancer. We also evaluated the effect of the p53 codon 72 polymorphism on clinicopathologic features. We examined blood from 170 Taiwanese women with breast cancer with polymerase chain reaction-restriction fragment length polymorphism for the genotypes of p53 codon 72. For the p53 codon 72 polymorphism, there were 31 p53-P/P72 (18.2%), 93 p53-R/P72 (54.7%), and 46 p53-R/R72 (27.1%) with the allele frequencies 0.54 for the p53-R72 and 0.46 for p53-P72, respectively. Our results indicate that there was more p53-P72 (40.6% in Asians vs. 26.4% in Caucasians) and twice the incidence of p53-P/P72 homozygotes (18% in Asians vs. 8% in Caucasians) among the Asian population. Patients with the p53-R/R72 variant were more likely to have a t1 tumor size status (55.2%) compared with patients with the P53-P/R72 (30.9%) or P53-P/P72 variant (36%). Our results support the hypothesis that genetic factors may contribute to the difference between Taiwanese or Asian breast cancer and Western breast cancer patient populations.

Figure 1

The p53‐P/P72 variant was identified by a single band (195 bp), the p53‐R/R72 variant produced two bands (85 bp and 110 bp), and the heterozygous p53‐R/P72 variant displayed three bands (195, 85, and 115 bp).