Expression and role of vascular endothelial growth inhibitor in sporadic clear cell renal cell carcinoma

Abstract

To evaluate the expression of vascular endothelial growth inhibitor (VEGI) in sporadic clear cell renal cell carcinoma (CCRCC) and explore its relationships between VEGI expression, pathologic grade and tumor staging. Western blot and immunohistochemical staining were used to detect the expression of VEGI in CCRCC cell line (786-O cells), CCRCC and paired normal kidney tissues. A total of 50 CCRCC cases were recruited. There were 37 males and 13 females with an average age of 53 ± 12 years. The tumor sizes were < 7 cm (n = 33) and ≥ 7 cm (n = 17). Their pathologic grades were G1 (n = 14), G2 (n = 22) and G3 (n = 14) and pathologic stages pT1 (n = 32), 10 pT2 (n = 10) and pT3 (n = 8). VEGI protein was predominantly located in cytoplasm. Compared with normal kidney tissues(mean optic density (MOD) of VEGI staining: 0.40 ± 0.16), it was lower in CCRCC tissues (MOD: 0.11 ± 0.06, P < 0.01). In addition, the positive rate of VEGI expression, the expression intensity and the MOD of VEGI protein were negatively correlated with the pathologic grade of CCRCC (r = -0.640, P < 0.01; r = -0.831, P < 0.01; r = -0.781, P < 0.01 respectively). The MOD of VEGI expression in ≥ 7 cm tumors (MOD, 0.08 ± 0.04) was significantly lower than that in < 7 cm tumors (MOD: 0.12 ± 0.06, P < 0.05). However, there was no correlations between the VEGI protein level and age, gender and pathologic stage of patients (P > 0.05). VEGI protein is predominantly located in cytoplasm. Compared with CCRCC tissues, VEGI protein level is higher in normal ones. In consideration of negative correlations between VEGI expression, pathologic grade and tumor size, it is implied that VEGI may play a negative regulatory role in the occurrence and development of CCRCC.