MAGEA9 is a member of the MAGEA gene family. The members of this family have their entire coding sequences located in the last exon, and the encoded proteins show 50 to 80% sequence identity between each other. The promoters and first exons of the MAGEA genes show considerable variability, suggesting that the existence of this gene family enables the same function to be expressed under different transcriptional controls. The MAGEA genes are expressed at a high level in a number of tumors of various histologic types, and are silent in normal tissues with the exception of testis and placenta. The MAGEA genes are clustered on chromosome Xq28. They may be implicated in some hereditary disorders, such as dyskeratosis congenita.