Molecular characterization of glutathione S-transferase, endothelial nitric oxide synthase and Vitamin D receptor genes in breast cancer cases

ABSTRACT

Enzymes of the Glutathione S-transferase system [GST] modulate the effects of exposure to several cytotoxic and genotoxic agents. Nitric oxide [NO] is constitutively synthesized in the endothelium by endothelial nitric oxide synthase [eNOS] and acts as a pleiotropic regulator involved in carcinogenesis. Vitamin D levels may influence breast cancer development. The vitamin D receptor [VDR] is a crucial mediator for the cellular effects of vitamin D and additionally interacts with other cell-signaling pathways that influence cancer development. To check for the association of polymorphisms of GST, eNOS3 and VDR genes with the susceptibility and severity of breast cancer in Egyptian cases. This work included 100 cases with breast cancer and 100 healthy individuals. The mean age of cases was 48.31 +/- 11.40 years. They included 100 females. DNA was amplified using PCR-RFLP for detection of polymorphisms related to eNOS3 and VDR, also DNA was amplified using PCR-SSP for detection of polymorphisms related to GST and calculating the odds ratios and their 95% confidence intervals. Total cases showed high significant frequency of eNOS3[-786] CC [P<0.05, OR=18.58] genotypes, GSTT1 [null] [OR = 2.68; CI 95%=1.51-4.75; p=0.001]. These were considered risk genotypes for disease susceptibility. On the other hand, total cases showed low significant frequency with homozygosity for eNOS3[-786] TT [P=0.01] and the GSTT1 gene was present in 42.0% of the cancers and in 66.0% of controls [OR = 0.37; CI 95%= 0.21-0.66; p=0.001]. These may be considered low risk genotypes. No significant difference in frequencies of null and present genotypes of GSTM1 and VDR FOKI in total cases compared to controls. Polymorphisms related to eNOS3[-786], GSTT1 and VDR FOKI genes may be considered genetic markers for BC among Egyptian cases. This may have potential impact on family counselling as well as future management plans