FAM50A, also known as DXS9928E, HXC26, XAP5 or 9F, is a 339 amino acid nuclear protein that belongs to the FAM50 family. Expressed ubiquitously with highest expression in fetal kidney, liver and brain, as well as adult heart, spleen, skeletal muscle, prostate and small intestine, FAM50A is thought to function as a transcription factor that may bind to DNA. FAM50A contains an SV40 large T antigen nuclear localization signal and a polymorphic CCG repeat region in its 5’-UTR. Defects in the gene encoding FAM50A may be associated with acute lymphoblastic leukemia, suggesting a possible role for FAM50A in carcinogenesis.