We have defined the chromosomal location of the human MAGE (melanoma antigen) gene family by polymerase chain reaction amplification of several segments of the MAGE genes from somatic cell hybrids containing well-defined groups of human chromosomes and hybrids containing human derivative chromosomes. The data show that the three known MAGE family members (MAGEs -1, -2, & -3) are syntenic and map to the human X chromosome region q27-qter. Because males and females are hemizygous for most X-linked genes, the frequency of antigen-loss variants for the MAGE system is expected to be greater in comparison to antigens encoded by somatic chromosomes. In this regard, we believe that patients enrolled in MAGE-specific immunotherapy trials should be carefully monitored for the presence of MAGE antigen-loss variants.
Supported by Grant 225-8 (to M. K. O.) from the Vince Lombardi Cancer Research Foundation.