High resolution two‐dimensional electrophoretic analysis of urinary proteins of patients with prostatic cancer

In an attempt to identify marker(s) for prostatic cancer, proteins in urines of normal and prostatectomized males and in men with cancerous prostate were analyzed. Only urines collected with protease inhibitors were examined. Two-dimensional (2-D) gel electrophoresis was used for high resolution separation of proteins and the electrophoretograms were either developed by double stain or the proteins were electrophoretically transferred onto nitrocellulose for immunological identification. The pool of each group exhibited similar relative positions of major protein spots. The study of normal and prostatectomized men identified two proteins denoted as A (36 kDa, pI 6-6.5) and B (23 kDa, pI 6.6), which were undetectable in the latter group. A visual comparison of the patterns of normals and patients with cancerous prostate revealed that both these proteins were undetectable in urines of men with malignant prostatic carcinoma (PCA) and benign prostatic hyperplasia (BPH) and hence may be useful in identifying prostatic carcinoma. Also, while protein C 43.5 kDA, pI 6-6.6) was discerned in normals its abundance, along with those of proteins D (40 kDa, pI 6-6.4) and E (26.5 kDa, pI 6-6.7), appeared to be higher in BPA than in PCA. Protein F (18-28 kDa, pI 4-5.5) was found in patients with BPH but was undetected in normals and men with PCA. Hence, it may become useful in distinguishing BPH from PCA. All the proteins, A to F, appear to be previously unidentified. Their further characterization is warranted.