Isolation of LEM domain-containing 1, a novel testis-specific gene expressed in colorectal cancers

Through analysis of genome-wide expression profiles on a cDNA microarray consisting of 23,040 human genes, we have been attempting to isolate novel molecular targets for diagnosis, treatment and prevention of colorectal carcinoma (CRC). Among the genes that were frequently transactivated in colorectal tumors, we identified a novel gene termed LEMD1 (LEM domain-containing 1) whose expression was elevated in 17 of 18 CRCs compared with their corresponding non-cancerous mucosae. Northern blotting revealed that LEMD1 was expressed only in testis among the 16 normal adult tissues examined. Subsequent analysis identified six alternatively spliced forms of the transcript in normal testis, but only one of them (656 nucleotides) was expressed in CRCs. Since the LEMD1 protein appears to fall in the category of cancer-testis antigens (CTAs), it may represent a promising target antigen for immunotherapy of CRCs.