KMT2A and cancer: Correspondingly, the mixed-lineage leukemia (MLL) family of proteins, MLL1, MLL2, MLL3, MLL4, SET-domain-containing 1A (SET1A), and SET1B, which all have the H3K4-methylating SET-domain, are frequently mutated in various cancers, including those of the breast, lung, large intestines, endometrium, and bladder [17].