The Study of Survivin Gene Promoter Polymorphism (-31G/C) in Breast Cancer in North West of Iran

Survivin gene, as an apoptosis inhibitor, plays an important role in development of breast cancer. The differential expression of survivin in cancer versus normal adult cells as well as an association between high expression of survivin and aggressive tumors has led to use of survivin as a molecular marker for diagnosis and prognosis of tumors. The underlying mechanism of survivin over expression in cancers is not recognized yet. There is a probability that some polymorphisms in this gene can result in uncontrolled manner of this gene. The C-31G, a widely studied polymorphism in the survivin promoter, could de-repress the cell cycle- dependent transcription of survivin gene, resulting in over expression of survivin. In this hospital- based, case- control study, we aimed to investigate the correlation between the genetic polymorphism of -31G/C, surviving promoter, and breast cancer (BC) in North West of Iran. In this case–control study, the -31G/C single nucleotide polymorphism (SNP) of survivin promoter in peripheral blood samples was collected from 94 breast cancer patients with pathologically confirmed BC and 82 healthy subjects. The data were analyzed by polymerase chain reaction- restriction fragment length polymorphism (PCR-RFLP) and gene sequencing. Statistical analysis showed that within breast cancer patients, genotype frequencies were 50%, 46.8% and 3.2% for -31G/G, -31G/C and -31C/C genotypes respectively, whereas they were 50%, 45.1% and 4.9 % for -31G/G, -31G/C and -31C/C genotypes in healthy individuals. Also the frequencies for -31 C allele were 26% and 27% in the cases and controls respectively. No statistically significant association was found between breast cancer and the variant genotypes (CC and CG). It seems that there was no significant association between -31G/C polymorphism, BC, and clinicopathological characteristics in the population of our study.