IMMUNOSTAINING FOR PROSTATE-CANCER ANDROGEN RECEPTOR IN PARAFFIN IDENTIFIES A SUBSET OF MEN WITH A POOR-PROGNOSIS

BACKGROUND: Knowledge of androgen receptor (AR) content could help pre dict hormone response and disease course in prostate cancer. However, determination of AR by biochemical assay is difficult. An immunohistoc hemical assay (ICA) would solve most difficulties and be especially us eful if it could be performed on paraffinized tissue. EXPERIMENTAL DES IGN: AR was studied in paraffin sections from 90 men for whom endocrin e response, survival (except one case), and/or biochemical AR was know n. After Ag retrieval in a microwave oven, a polyclonal anti-AR Ab was used with the peroxidase antiperoxidase method. Results were semiquan tified using a Histoscore (Hscore) and were correlated with biochemist ry, endocrine response, and survival. RESULTS: Only 15 patients were A R-negative. AR-ICA did not correlate with biochemistry, Gleason score, stage, or ethnicity but did correlate with endocrine response and sur vival. The average Histoscore was significantly lower in patients with progressive disease (p < 0.05). In a Cox's regression analysis of sur vival (mean follow-up = 30 months) AR-ICA was a significant predictor fp = 0.015). Risk of death was 2.5 times greater for a patient with a negative assay compared with one with a positive result. CONCLUSIONS: Our data indicate that AR status by ICA may be a useful predictor of s urvival and endocrine response in prostate cancer. Further studies are needed to confirm these results because the assay could impact signif icantly on management.