The drugs, which received FDA approval for cancer treatment since 2011, inhibit the catalytic activity of such enzymes as steroid 17alpha-monooxygenase (CYP17A1), poly (ADP-ribose) polymerases (PARPs), thymidylate synthase (TS), topoisomerase (TOP) and enhancer of zeste homolog 2 (EZH2) (Figure 6). This evidence concerns the gene EZH2 and cancer.