EXPRESSION OF THE TUMOR-ASSOCIATED GENE MN - A POTENTIAL BIOMARKER FOR HUMAN RENAL-CELL CARCINOMA

MN is a novel cell surface antigen originally detected in human HeLa c ells. Although it is also expressed in normal gastric mucosa, this ant igen was previously found to be expressed in cells with a malignant ph enotype in certain tissues of the female genital tract (cervix and ova ry). Using an oligonucleotide primer set specific for MN-complimentary DNA, we performed reverse transcription-PCR assays on RNAs extracted from human cell lines and tissues to evaluate whether this marker migh t be expressed at other sites. RNA libraries extracted from normal hum an heart, lung, kidney, prostate, peripheral blood, brain, placenta, a nd muscle were negative for MN expression. RNAs extracted from liver a nd pancreatic tissue were positive for MN expression. Three of six ren al cancer cell lines tested revealed MN expression. In addition, 12 of 17 samples of human renal cell carcinoma tissue tested positive for M N, all 12 of which were clear cell adenocarcinomas. This survey identi fied a unique association of MN expression with renal cell cancers, es pecially those of the clear cell variety, suggesting that MN is a pote ntial marker for the diagnosis, staging, and therapeutic monitoring of renal cell carcinoma in humans.