HPGDS and neoplasm: Glutathione S-transferases (GSTs) are a family ofmultigene isoenzymes involved in the addition of glutathione (GSH)to electrophilic substrates as a detoxification strategy,67,68 being particularly active in tumor processes.69 In vertebrate GSTs, the hydroxyl group of a conserved tyrosylresidue located near the N-terminus (domain I) is believed to stabilizethe thiolate anion of GSH by H-bond interaction (TyrOH···SG–).