Expression and significance of FOXP1, HIF-1a and VEGF in renal clear cell carcinoma.

PURPOSE To investigate the expressions of FOXP1, hypoxia inducible factor (HIF)-1a and vascular endothelial growth factor (VEGF) in renal cell carcinoma of the clear type (CCRCC) and their relationship with the patient clinicopathological features. METHODS The expressions of forkhead box-P1 (FOXP1), HIF-1a and VEGF in 55 cases of CCRCC tissues were determined using immunohistochemistry. Then, their correlations with clinical stage, histological grade and lymph node metastasis were analyzed using chi-square test. RESULTS Thirty-seven of the 55 cases (67.3%) of CCRCC expressed FOXP1 with an abnormal expression rate of 38.2% (21/55), in which there were 10 cases with positive FOXP1 both in the nucleus and the cytoplasm and 11 cases with positive FOXP1 in cell membrane. The abnormal expression rate of FOXP1 inhigh grade CCRCC (G3/G4) was significantly higher than that in low grade CCRCC (G1/G2, p<0.05). FOXP1 expression was significantly correlated with the expression of HIF1 and VEGF (r=0.54, p<0.01 and r=0.37, p<0.05, respectively), but was not obviously correlated with clinical stage, lymph node metastasis and 5-year overall patient survival (p>0.05). CONCLUSION Abnormal expression of FOXP1 and its deficiency are common events in CCRCC. Abnormal expression of FOXP1 may create progression of tumor from low grade to high grade by regulating the HIF-1-VEGF pathway.