IDENTIFICATION OF HUMAN TESTIS-SPECIFIC TRANSCRIPTS AND ANALYSIS OF THEIR EXPRESSION IN TUMOR-CELLS

Tumor-specific antigens recognized by autologous T lymphocytes are enc oded by genes, including those of the MAGE, BAGE, and GAGE gene famili es, that are expressed in a significant fraction of tumors of various types, but not in normal adult tissues, except for testis where they a ppear to be expressed in germ cells. Because male germ cells are known to express many genes that are not expressed in other normal adult ti ssues, we wished to determine whether most of these genes are occasion ally activated in tumor cells. Representational difference analysis wa s used to obtain testis-specific transcripts. The expression of 15 tes tis-specific cDNA sequences was tested by RT-PCR in a series of tumor cell lines. Only one cDNA sequence showed a significant level of expre ssion in some tumor cell lines. Remarkably, this cDNA clone proved to be a new gene of the MAGE family. These results suggest that MAGE, BAG E, and GAGE genes belong to a minor subset of testis-specific genes th at is often activated in tumors of various types, whereas most testis- specific genes are either never or very rarely activated in tumors. (C ) 1997 Academic Press.