TKT and cancer: Later studies have shown that ponicidin can promote the cell-killing activity of antiherpes prodrugs acyclovir (ACV) and ganciclovir (GCV) in human cancer cells expressing herpes simplex virus thymidine kinase (HSV-TK), and the combined use of ponicidin with GCV or ACV may produce high cytotoxicity in viral TK-expressing cancer cells and lead to a rapid and enhanced tumor elimination in vivo [5].