Gamma-seminoprotein--a new tumour marker in prostatic cancer? Results of a pilot study

Serum levels of gamma-seminoprotein (GSM), prostate specific antigen (PSA) and prostate specific acid phosphatase (PAP) were examined, using enzyme immunoassay, in 250 patients with prostatic disease. The results indicated that the highest specificity was obtained with GSM (94%) and the lowest with PSA (60%). In contrast, the highest sensitivity in newly detected carcinomas (n = 41) was obtained with PSA (71%), whereas that of GSM (51%) was comparable to that of PAP (44%). Of 41 patients with newly detected prostatic cancer, 35 (85%) showed a significant increase in at least 1 of the tumour markers. Five of 6 patients whose markers were within normal limits had incidental carcinomas. During follow-up, PSA was raised in 88%, GSM in 66% and PAP in 55% within 12 months prior to clinical progression. Our results suggest that the determination of GSM may be of value in the serological detection and monitoring of prostatic cancer. These findings must be confirmed by further studies with larger numbers of patients and longer follow-up.