Increased fatty acid synthase expression in prostate biopsy cores predicts higher Gleason score in radical prostatectomy specimen

BACKGROUND Fatty acid synthase (FAS) is highly expressed in various types of cancer, and elevated expression of FAS has been suggested to be a predictor of tumor aggressiveness and poor prognosis. We examined whether FAS expression in prostate biopsy cores could predict the pathological characteristics of radical prostatectomy (RP) specimens. METHODS Paraffin-embedded prostate biopsy cores, obtained from 102 patients who subsequently underwent RP, were immunostained with polyclonal anti-FAS antibody. The staining intensity was categorized into non-staining, weak, moderate, and strong. Tumors with moderate or strong immunostaining were considered to show high FAS expression, and other tumors were considered to show low FAS expression. The relation between the FAS expression status in biopsy cores and pathological parameters in RP specimens was analyzed. RESULTS The FAS expression in the biopsy cores of 64 of the 102 tumors (63%) was high, whereas it was low in the biopsy cores of the other 38 tumors (37%). High FAS expression was significantly associated with Gleason Score (GS) ≥ 7 in RP specimens (p< 0.0001). In multivariable logistic regression analyses, GS ≥7 in biopsy cores (p <0.0001), higher preoperative PSA (p = 0.0194), and high FAS expression (p = 0.0004) were independent predictors of GS ≥ 7 in the RP specimen. CONCLUSIONS Increased FAS expression in prostate biopsy cores could be a novel parameter for predicting higher GS in RP specimens. The treatment strategy for patients with high FAS expression in prostate biopsy cores should be carefully determined.