Association between GSTP1 Genotypes and Hormone Receptor Phenotype in Invasive Ductal Carcinomas of Breast

Abstract

Eighty six cases of invasive ductal breast carcinomas were utilized to investigate GSTP1 polymorphisms incertain immunohistochemistry (IHC) subtypes of breast cancer with respect to ER, PR and HER2 expression.The frequency of wild allele homozygote, heterozygote and variant allele homozygote genotypes were 46.5%,52.3% and 1.16% respectively; Whereas 54.3% of the control subjects were GSTP1 wild type allele homozygous,40.0% were heterozygous and 5.71% mutant allele homozygous. There was dramatic inverted relation betweenpositive IHC ER staining and increasing grade of tumors in general (100%, 88.6%, 40.4%) and especially amongtumors with heterozygote genotype of GSTP1 (70%, 35.4%, 22.7). There was increase in positive IHC HER2staining consistent with higher grades in general (20%, 29.6%, 50.0%), especially among tumors with GSTP1wild allele homozygote genotype (5.0%, 9.1%, 31.8%). A remarkable reverse relation was also observed betweenthe fraction of IHC hormone receptor phenotype ER+/PR+/ HER2- and increased grade of tumors (60.0%,45.5%, and 27.3%) especially among tumors with GSTP1 heterozygote genotype, and a similar link was notedregarding ER+/PR-/ HER2- and tumor grade. There was increase in frequency of ER-/PR-/ HER2- (0.0%, 6.8%,and 18.2%) and ER-/PR-/ HER2+ (0.0%, 4.54%, and 40.9%) consistent with the higher grades of tumors ingeneral and especially GSTP1 heterozygote genotype tumors. As a conclusion, there is no correlation betweenGSTP1 polymorphism and increased risk of breast cancer i.e. the mutant allele is randomly distributed in cancerand control cases. However, there is a link between GSTP1 genotypes and hormone receptor expression statusand certain phenotypes of breast cancer, which may have clinical importance.