PNP and hepatocellular carcinoma: Among them, the most commonly used suicide gene/prodrug pairs in HCC treatment include herpes simplex virus thymidine kinase/ganciclovir (HSVtk/GCV), cytosine deaminase/5‐fluorocytosine (CD/5‐FC) and purine nucleoside phosphorylase/fludarabine phosphate (PNP/FP)87 (Table S5).