MLL4 a protein which contains multiple domains including a CXXC zinc finger, three PHD zinc fingers, two FY-rich domains, and a SET (suppressor of variegation, enhancer of zeste, and trithorax) domain. The SET domain is a conserved C-terminal domain that characterizes proteins of the MLL (mixed-lineage leukemia) family. MLL4 is ubiquitously expressed in adult tissues. It is also amplified in solid tumor cell lines, and may be involved in human cancer