Overexpression of fatty acid synthase in human urinary bladder cancer and combined expression of the synthase and Ki-67 as a predictor of prognosis of cancer patients.

To investigate the status of fatty acid synthase (FAS) in bladder tumors and evaluate its prognostic significance, we immunohistochemically examined the expression of FAS in normal urothelium, carcinoma in situ (CIS), and urothelial carcinoma (UC) in cystectomized bladder. In normal urothelium, only the surface layer expressed FAS, whereas the protein was detected in the basal layer or whole layer of CIS and UC in every specimen. Of the clinicopathological factors in UC, pathological tumor (pT) stage and histological grade were significantly correlated to FAS expression (P = 0.002, P < 0.0001, respectively). Univariate analysis for disease-specific survival indicated that the combination scores of FAS and Ki-67 expression, which were not associated with each other, was a more predictive variable than the individual score of each protein expression. Kaplan-Meier analysis showed that high combination scores of both proteins were significantly associated with poor prognosis (P = 0.04). In conclusion, FAS expression can be a biomarker for tumor aggressiveness and loss of differentiation of bladder cancer, and the evaluation of its expression level in combination with Ki-67 labeling index may be a precise predictor for poor prognosis of cancer patients.