MAGEB1 is a member of the MAGEB gene family. The members of this family have their entire coding sequences located in the last exon, and the encoded proteins show 50 to 68% sequence identity to each other. The promoters and first exons of the MAGEB genes show considerable variability, suggesting that the existence of this gene family enables the same function to be expressed under different transcriptional controls. This gene is localized in the DSS (dosage-sensitive sex reversal) critical region, and expressed in testis and in a significant fraction of tumors of various histological types. This gene and other MAGEB members are clustered on chromosome Xp22-p21.