Glutathione S-Transferase Pi expression in invasive ductal breast carcinoma

Abstract

Glutathione S-transferase pi (GST-pi) is a Phase II detoxification enzyme that has recently been implicated in protection against apoptosis. This study finds that over-expression results in higher recurrence risk in invasive ductal breast cancer patients with or without adjuvant chemotherapy treatment. GST-pi expression is generally found to be associated with decreased apoptosis and this effect, modulated by oxidative stress. The co-expression of GST-pi with Bcl-2 in many tumours results in its accumulation in the nucleus. Although not associated with the level of expression of metallothionein (another detoxification enzyme found to be associated with improved recurrence-free survival in patients receiving adjuvant chemotherapy), GST-pi expression is associated with p-glycoprotein (Pgp) and Y-box binding protein-1 (YB-1) expression. Direct interaction between YB-1 and Pgp can be demonstrated using the computer-based Resonant Recognition Model and YB-1 expression appears to confer resistance to anthracycline-based therapies.