The Glutathione S-transferase π (GST) family of enzymes is a group of typical Phase II detoxification enzymes and is found in many prokaryotes and eukaryotes. Of these enzymes, GSTπ catalyzes the conjunction between GSH and its electrophilic substrates upon exposure to damaging free radicals. Besides metabolite detoxification, GSTπ also exhibits ligand-binding properties that initiate cellular apoptosis when triggered by cellular stress. Further research has also demonstrated that GSTπ is expressed abundantly in tumor cells and associated closely to carcinogenesis, tumor formation, and chemotherapy resistance.