IMMUNOHISTOCHEMICAL ANALYSIS OF THE DISTRIBUTION OF THE HUMAN ATPASE (HASNA-I) IN NORMAL-TISSUES AND ITS OVEREXPRESSION IN BREAST ADENOMAS AND CARCINOMAS

Human ATPase (hASNA-I) is a novel human gene recently cloned on the ba sis of homology to the arsA gene of bacteria. Its protein product is a n ATPase that is free in the cytoplasm and bound in the perinuclear ar ea and nucleolus in human cells. We prepared the hASNA-I-specific 5G8 monoclonal antibody and used it to investigate the expression of hASNA -I in normal human tissues and breast cancers. hASNA-I was detected im munohistochemically only in the epithelial cells of the liver, kidney, and stomach wall, in the adrenal medulla, in the islet cells of the p ancreas, in the red pulp of the spleen, and in cardiac and skeletal mu scle. No staining was observed in the uterus, testis, lung, thyroid, c erebellum, and large intestine. Although no staining was also observed in normal breast tissue, all four cases of breast fibroadenomas and a ll 15 cases of either primary or metastatic breast carcinoma demonstra ted increased staining. No embryological or functional common denomina tor is readily apparent. However, the increased expression in malignan t breast cells is of particular interest with respect to the use of th is antibody for screening of cytological specimens.