Altered expression of enzymes involved in phase II of drug metabolism, including glutathione-S-transferases (GSTs), gamma-glutamyl transferases (γGTs), uridine diphospho-glucuronosyltransferases (UGTs), thiopurine methyltransferases (TPMTs), and dihydropyrimidine dehydrogenases (DPDs) in cancer cells may enhance their MDR [108,110]. Here, HPGDS is linked to cancer.