Background and purpose: The association between metabolic syndrome (MS) and renal cell carcinoma (RCC) is still unknown. The aim of this study was to elucidate how MS correlates with the prevalence and malignancy of RCC. Methods: This study enrolled 398 RCC patients (350 clear cell RCC patients

5 XP11.2 translocation RCC patients

16 papillary RCC patients and 27 chromophobe RCC patients)

160 normal persons

and 32 benign renal tumor patients. The metabolic status of the patients was assessed

and the link between MS and the prevalence or malignancy of RCC was calculated. Results: Clear cell RCC patients had significantly higher rates of hypertension

higher body mass index (BMI) and longer waist circumference. Forty-eight percent clear cell RCC patients had MS

while the number was 33% for papillary RCC

26% for chromophobe RCC

0% for XP11.2

17% for AML

and 25% for normal people. MS patients had significant higher rates of having clear cell RCC than no-MS patients

however this kind of difference was not seen in other types of RCC. Clear cell RCC patients with higher Furhman grade had lower rates of MS. Conclusion: Patients with MS are more likely to develop clear cell RCC. Patients with high Furhman grade tumors have low MS rates

indicating that high grade tumor may have other originating mechanisms other than metabolic disorders.