EXPRESSION OF GALACTOSYLTRANSFERASE IN PROSTATIC TUMORS

Galactosyltransferase (GalTase) has been discovered on a variety of ce lls where it is believed to be involved in cell-cell adhesion and cell -substratum adhesion as well as in metastasis of carcinoma cells. This immunohistochemical study was undertaken to identify the topography a nd the cellular distribution of GalTase in normal prostatic tissue, be nign prostatic hyperplasia (11 cases), and prostatic carcinoma (26 cas es). Immunoreactive GalTase was found to be exclusively associated wit h carcinoma cells and with premalignant epithelial cells in prostatic hyperplasia. In highly differentiated carcinomas, most of the carcinom a cells are positive for GalTase, whereas in poorly differentiated tum ors, GalTase immunoreactivity was restricted to a subset of carcinoma cells with obviously invasive behavior At the cellular level, GalTase was localized in the cytoplasm and at the cell membrane. In sections o f normal prostatic tissue, as well as in unaltered acini of prostatic hyperplasic tissue, GalTase was not expressed. Fibroblasts, smooth mus cle cells, and endothelial cells of the prostatic stroma were also con sistently negative. With the use of immunoblots, we could confirm the presence of GalTase with a molecular mass of 45 kDa in the extracts of benign prostatic hyperplasic tissue and in prostatic carcinoma tissue bur not in normal prostatic tissue. The results of our immunohistoche mical study suggest that GalTase is a valuable marker to diagnose neop lastic transformation in prostatic tissue.