Biochemical profiles of prostatic fluid from normal and diseased prostate glands

The attempt to identify changes in the biochemical composition of prostatic fluid that might accompany and characterize disease states in the prostate was stimulated by two assumptions based on observations. First, the composition of prostatic fluid was judged to be likely to reflect the metabolic status of at least the epithelial cells accurately. Secondly, the metabolic changes preceding or associated with the development of carcinoma in the prostate seemed likely to be diffuse rather than limited to the histologically abnormal prostatic cells. As a consequence of these assumptions, prostatic fluid obtained from the urethra by digital massage of the prostate was evaluated microscopically and subjected to numerous analytical procedures. Differences in lactate dehydrogenase (LDH) isoenzymes, complement C3, and transferrin concentrations in the prostatic fluid of men with histologically identified carcinoma (Ca) and benign prostatic hyperplasia (BPH) have been observed. The ratio of LDH-5/ LDH-1 was found to have a mean value of 5.94 +/- 0.25(S.E.) in 98 determinations on 83 patients with Ca, and 1.84 +/- 0.14 in 212 determinations on 142 patients with BPH with 10 or less white blood cells per high power field (WBC/hpf) on microscopic examination of the prostatic fluid. Fluid from 52 patients with BPH with greater than 10 WBC/hpf (84 determinations) had a mean ratio of 5.85 +/- 0.88 and from 286 patients with greater than 10 WBC/hpf without an established histologic diagnosis (460 determinations) of 3.12 +/- 0.21. Two hundred twenty-two men under 45 years of age (255 determinations) judged to have a normal prostate clinically had a mean ratio of 0.67 +/- 0.05. The mean transferrin concentration in 44 patients (51 determinations) with Ca was 47.03 +/- 3.76mg/100 ml, in 59 patients with BPH (90 determinations) was 12.97 +/- 1.20, in 23 patients with BPH with > 10 WBC/hpf in the prostatic fluid (38 determinations) was 14.93 +/- 2.19, in 87 patients with > 10 WBC/hpf (92 determinations) was 13.42 +/- 1.41, and in 33 patients less than 45 years of age with clinically normal prostates (33 determinations) was 7.45 +/- 1.08. The mean complement C3 concentration in 46 patients with Ca (57 determinations) was 17.48 +/- 1.60, in 58 patients with BPH (85 determinations) was 3.83 +/- 0.55, in 24 patients with BPH with > 10 WBC/hpf (39 determinations) was 5.87 +/- 0.68, in 93 patients with > 10 WBC/hpf (98 determinations) was 4.47 +/- 0.53, and in 34 patients less than 45 years of age (34 determinations) was 2.06 +/- 0.43. The mean ratio of LDH-5/LDH-1 was significantly greater for Ca than BPH with 10 or less WBC/hpf in the prostatic fluid. The mean concentrations of transferrin and complement C3 were significantly greater in Ca than in all other groups studied. No obvious relationship between stage of disease and these findings was observed. These observations support the suggestion that determination of prostatic fluid composition assists in identifying men with a high risk of cancer of the prostate.