Purpose: Fatty acid synthase is a key enzyme in the de novo biosynthesis of fatty acids. Increased fatty acid synthase expression and its association with tumor aggressiveness and poor prognosis have been demonstrated in various human malignant tumors. We investigated fatty acid synthase expression in patients with renal cell carcinoma and its impact on clinicopathological parameters. Materials and Methods: Fatty acid synthase expression in 120 patients with renal cancer was examined by immunohistochemistry. The relationship between fatty acid synthase expression status and various clinicopathological parameters was analyzed. Survival analysis was performed using the log rank test and a Cox multivariate hazard model. Results: Of 120 tumors 18 (15%) showed positive fatty acid synthase expression, which was significantly associated with advanced pathological T stage (pT3-4, p = 0.0009), regional lymph node metastasis (p = 0.0429), distant metastasis (p = 0.0042), higher histological grade (G3, p = 0.0017) and microvascular invasion (p = 0.0357). Patients with positive fatty acid synthase expression had significantly shorter cancer specific survival than those with negative FAS expression (p < 0.0001). Multivariate Cox proportional hazards model analysis demonstrated that positive fatty acid synthase expression was an independent predictor of shortened cancer specific survival (p = 0.0363, HR 3.736). Conclusions: Increased FAS expression could be an indicator of tumor aggressiveness and poor prognosis of renal cell carcinoma. Patients with fatty acid synthase positive tumors should be followed closely and carefully, and adjuvant therapy should be considered.
