PRDM9 and cancer: Today many epidrugs are being tested in cancer, and small molecule inhibitors already exist capable of targeting the main types of epigenetic regulators: DNMT inhibitors, histone acetyltransferase inhibitors, histone methyltransferase inhibitors, histone deacetylase inhibitors, histone demethylase inhibitors, and others (Berdasco and Esteller, 2019).