Two-dimensional electrophoretic analysis of human prostatic fluid proteins.

The heterogeneous mixture of proteins present in expressed prostatic fluid from forty-nine men over 25 years old was analyzed on two-dimensional electrophoretic gels stained with silver. Samples were collected from men diagnosed with chronic prostatitis, urinary tract infection, benign prostatic hypertrophy (BPH), and prostatic carcinoma. Reference patterns were developed for all proteins observed in electrophoretograms. Over 1000 distinct proteins are contained in the comprehensive proteins pattern of prostatic fluid; however, only 18 proteins were common to all samples. No proteins unique to fluids from men with BPH or prostatic cancer were observed. Some proteins in the common proteins reference pattern of BPH patients were not seen in samples from men with prostatic cancer. Our preliminary results indicate that a series of proteins tentatively identified as variants of prostatic acid phosphatase appeared elevated in all BPH fluids but was absent or below limits of detection in samples from men with prostatic carcinoma. Our studies indicate that proteins secreted in prostatic fluid reflect physiological changes in the prostate, and certain changes may be useful indicators of malignant transformation.