Mutated melanoma-associated antigen 1 (MUM-1) is a melanoma-associated antigen (MAA). MUM-1 belongs to the mutated or aberrantly expressed type of MAAs, along with antigens such as CDK4, beta-catenin, gp100-in4, p15, and N-acetylglucosaminyltransferase V. It is highly expressed in several types of human cancers. The PWWP domain, named for a conserved Pro-Trp-Trp-Pro motif, is a small domain consisting of 100-150 amino acids. The PWWP domain is found in numerous proteins that are involved in cell division, growth and differentiation. Most PWWP-domain proteins seem to be nuclear, often DNA-binding, proteins that function as transcription factors regulating a variety of developmental processes.