IMMUNOHISTOCHEMICAL DETECTION OF A FATTY-ACID SYNTHASE (OA-519) AS A PREDICTOR OF PROGRESSION OF PROSTATE-CANCER

Prostate cancer is the most common newly diagnosed non-skin cancer and the second leading cause of cancer death in men, It is a unique neopl asm because of the large discrepancy between its clinical incidence an d the much higher incidence of latent cancer. Predicting the prognosis of prostate cancer, especially the cancers detected incidentally or b y screening, remains a clinically important problem. Immunoreactivity for Once-antigen 519 (OA-519), a recently described fatty acid synthas e (FAS), has been associated with poor prognosis in breast cancers. Th e authors have previously shown that its detection in prostate cancer correlated with high-grade, large volume, and advanced stage tumors. T his study examines the association between OA-519 immunoreactivity in primary prostate cancer and disease progression. The authors used immu nohistochemistry with an affinity-purified anti-OA-519 antibody and ex amined primary prostate cancers (stages A1 to D1) from 99 men with a m ean follow-up of 4 years (range = 2 to 9.3), Survival analysis was use d to evaluate differences in progression-free survival. OA-519 immunor eactivity was seen in 56 (57%) of the 99 primary prostate cancers exam ined, OA-519-positive cancers were more likely to progress than the OA -519-negative cancers (P<.04). Univariate survival analysis showed tha t OA-519 (FAS), histological grade (Gleason score), and clinical stage were significant predictors of disease progression. Multivariate anal yses of all cases showed that only histological grade was significant. However, multivariate analysis of the 85 cancers with Gleason scores 2-7 tie, low to intermediate grade) showed OA-519 (FAS) immunoreactivi ty to be the only statistically significant predictor of cancer progre ssion (P<.02). Expression of the fatty acid synthase OA-519 by prostat e cancers is potentially a clinically useful predictor of disease prog ression. It appears to be independent of histological grade (Gleason s core), at least in cancers with low to intermediate grades, Further st udies are needed to evaluate the role of fatty acid synthase in malign ancy and the potential therapeutic implications of enzyme blockers. Co pyright (C) 1996 by W.B. Saunders Company