L3MBTL1 and neoplasm: The E3 ubiquitin ligase RNF8 is proposed to be able to destroy the competing proteins of H4K20me2, such as the malignant-brain-tumor (MBT) protein L3MBTL1 (L3MBTL1) and JMJD2A at DSBs, to make H4K20me2 accessible to 53BP1 [11, 30, 33, 70].