Breast cancer is one of the most common cancer affecting women and the recent research is focused on identifying new genetic and epigenetic prognostic and predictive factors. Glutathione S-transferase P1 (GSTP1) is abiotransformation enzyme expressed in normal breast epithelial cells which can be epigenetically inactivated in breast cancer. We have shown, that application of nested two-stage methylation-specific PCR (MSP) is asuitable method for analysis of epigenetically silenced GSTP1 in formalin-fixed paraffin-embedded (FFPE) tissues from breast cancer patients. Of 45 breast tumors, 11 (24, 4%) were found to have methylated GSTP 1promoter region. We were able to demonstrate the correlation between the hypermethylation of the GSTP1 promoter region and histological grade of the tumor (p
Keywords: breast cancer, prognostic factors, hypermethylation, GSTP1, methylation-specific PCR.