Although the precise role of the glutathione detoxification pathway in the MDR phenomenon has not yet been fully elucidated, the isoenzymes of the glutathione-S-transferase (GSTs), namely the subclass GSTpi (EC 2.5.1.18), have been extensively reported to be overexpressed in tumour cells displaying the MDR phenotype (Keith et al, 1990; Buser et al, 1997; Ferrandina et al, 1997; Frassoldati et al, 1997; Silvestrini et al, 1997; Boku et al, 1998; Stoehlmacher et al, 2002; Oudard et al, 2002; Cullen et al, 2003; Galimberti et al, 2003; Bennaceur-Griscelli et al, 2004). This evidence concerns the gene HPGDS and neoplasm.