ABSTRACT
Breast cancer is the most common oncological disease in women worldwide. Genetic predisposition to breast cancer can be associated with single-nucleotide polymorphisms (SNPs), which are observed in many women. Such gene polymorphisms, in combination with nutritional and environmental factors, can affect breast cancer development. The tumor suppressor TP53 and its negative regulator MDM2 play crucial roles in carcinogenesis. Previous case-control studies have revealed that TP53 72Arg > Pro and MDM2 309T > G polymorphisms contribute to the risk of common cancers. However, the relationship between these two functional polymorphisms and breast cancer susceptibility in the Saudi population has not been explored. In this study, we performed a case-control study of patients with breast cancer and healthy controls in a Saudi population using TaqMan-based real-time PCR. We found an increased breast cancer risk associated with the MDM2 GG [odds ratio (OR) = 2.79, 95% confidence interval (CI) = 2.04-3.92] and TG [OR = 1.43, 95% CI = 1.12-2.02] genotypes. An increased risk was also associated with the TP53 Pro/Pro genotype (OR = 2.19, 95% CI = 1.54-3.06) compared with the Arg/Arg genotype. The gene-gene interaction of MDM2 and TP53 polymorphisms increased breast cancer risk in a multiplicative manner (OR for the presence of both MDM2 GG and TP53 Pro/Pro genotypes = 7.71, 95% CI = 3.49-17.54). These findings suggest that polymorphisms of MDM2 and TP53 genes may be a genetic modifier for developing breast cancer in this ethnic population in the Arab world.
Subject(s)
Arabs , Breast Neoplasms/ethnology , Breast Neoplasms/genetics , Polymorphism, Single Nucleotide/genetics , Proto-Oncogene Proteins c-mdm2/genetics , Tumor Suppressor Protein p53/genetics , Adult , Arabs/ethnology , Arabs/genetics , Case-Control Studies , Ethnicity/ethnology , Ethnicity/genetics , Female , Genetic Predisposition to Disease/ethnology , Genetic Predisposition to Disease/genetics , Humans , Middle Aged , Risk FactorsABSTRACT
Certain single nucleotide polymorphisms (SNPs) in genes like p21 or bcl2 increase susceptibility to breast cancer but it has not, until now, been clear whether common polymorphic variants in the same genes also increase risk in Saudi Arabian population. The aim of this study was therefore to determine whether polymorphisms of p21 or Bcl2 might be associated with an increased risk of breast cancer in Saudi women. p21 (rs733590) C/T SNP was not found to be associated with breast cancer pathogenesis. However, we found that a reverse mutation T/C might be linked with breast cancer occurrence. Bcl2 genotypes were marginally associated overall with breast cancer risk. In addition, the alleles of this gene were significantly associated with risk of breast cancer. The allelic frequency of G was higher (0.68) in patients than in healthy women. AA vs. AG+GG genotype [OR=3.56 (1.24-10.68); P=0.008] was the dominant genotype. It is likely that these genes conferring measurably increased risks of breast cancer in our study population.
