Besides LSD1, enzymes involved in histone lysine methyltransferases and lysine demethylases, such as SUV39H1 (KMT1A), SETDB1 (KMT1E), KDM4B, and KDM5A, have been found to be involved in the DDR, suggesting that their inhibitors have combination therapy potential with PARPi for cancer treatment56,57. This evidence concerns the gene KDM4B and cancer.