Comparison of clinicopathological parameters with FoxM1 expression in renal cell carcinoma

To investigate the relationships between expression of forkhead box M1 (FoxM1) and clinicopathologic parameters and Ki-67 expression in patients with renal cell carcinoma (RCC).

A total of 67 cases of RCC including 47 cases of clear cell RCC (ccRCC), five cases of papillary RCC (pRCC), eight cases of chromophobe RCC (chRCC), four cases of unclassified (with sarcomatoid pattern) RCC (sRCC), and three cases of multilocular RCC (mRCC) were included to this study. The expression of FoxM1 protein was assessed in 67 samples of RCC using immunohistochemical methods and the relationship between the expression levels of FoxM1 with clinicopathological characteristics and Ki-67 expression of RCC patients. For statistical analysis, the cases were grouped into the ccRCC and non-ccRCC group.

Immunohistochemistry analyses showed that FoxM1 protein expression in 47 ccRCC samples was significantly correlated with tumor size, stage, nuclear grade, capsule invasion, perinephric fat invasion, and Ki-67 expression (P<0.05 for all); whereas, no correlations were found in patients' age, gender, and lymph node metastasis (P>0.05 for all). In 20 non-ccRCC; overexpression of FoxM1 was strongly associated with tumor size (P<0.05). There was no relationship between FoxM1 expression with other clinicopathological parameters and Ki-67 expression in non-ccRCC (P>0.05 for all).

This study showed that FoxM1 have a progressive oncogenic role in ccRRC. Our results suggested that higher expression of FoxM1 in tumor tissues predicts a locally aggressive behavior and poor outcome of patients with ccRCC, but not in patient with non-ccRCC.