Detection of tumor-associated membrane proteins in prostate and bladder carcinomas by means of protein blotting.

Analysis of membrane proteins by Western blotting has revealed both overexpression of proteins of molecular weight 10-200 kD (in particular, of proteins of MW less than 43 kD) and increased glycosylation in a xenografted human small cell undifferentiated prostatic carcinoma, and in two xenografted human bladder tumor cell lines compared with preparations from normal human tissue. Of potential functional significance were: a) a 43 kD protein in the bladder line, UCRU-BL-13, which demonstrated increased synthesis and a marked increase in the degree of glycosylation, and b), a 28 kD ConA-binding protein in prostatic tissue which was absent in normal tissue, present in intermediate quantity in a benign hyperplasia and greatly overexpressed in small cell carcinoma. This study demonstrates the utility of the protein blotting/autoradiography technique for the investigation of tumor membrane proteins.