CHEK2 and melanoma: Moreover, another HDACi, sodium butyrate, induced the downregulation of the NHEJ components Ku70, Ku80, and DNA-PK in human melanoma cell lines [40], whereas in acute myeloid leukemia cells, dacinostat (LAQ824) and entinostat (SNDX-275) downregulated BRCA1 (breast cancer type 1), RAD50, Ku80, EXO1 (exonuclease 1), and CHK2 (checkpoint kinase 2) [41].