Immunohistochemical expression of vascular endothelial growth factor (VEGF) does not correlate with microvessel density in renal cell carcinoma

The aim of present study was to investigate the relationship between the immunohistochemical expression of vascular endothelial growth factor (VEGF) and microvessel density (MVD) assessed by CD31 and endoglin (CD105) in renal cell carcinoma (RCC). Specimens from 45 cases of RCC. were formalin-fixed, paraffin embedded, and sections were stained with H&E. Additional sections from each case were stained for VEGF, CD31, CD105, and alpha smooth muscle cell actin (SMA). VEGF immunohistochemical expression was estimated as negative (0), weak positive (+l), moderate positive (+2), and intense positive (+3). Microvessel density (MVD) was estimated on 5 hot spots (x400) from each case, and the arithmetic media was the final result. MVD was separately calculated on slides stained with CD31 and CD 105. The rate between mature and immature blood vessels was calculated on slides stained with CD31/CD105/SMA. Statistic analysis was performed with SPSS10.0. The immunoreaction for VEGF was positive in epithelial cells of the renal tubules, and occasionally, in endothelial cells. In RCC, tumor cells were positive in 34 from 45 cases (75.5%). 11 cases were negative, 14 were slightly positive (+1), 13 moderate (+2), and 7 intense (+3). No relationship was found between the expression of VEGF and pathological form and nuclear grade, excepting for the chromophilic variant (3 cases, all positive). CD31 was positive in all cases, and CD105 in 39 cases. The mean values of MVD on slides stained for CD31 and CD105 were: 31.68 (range 9.8-60.2)/20.66 (range 4.2-52.8). The rate CD31/SMA positive blood vessels was 1/0.62. VEGF was expressed in 75.5% of 45 cases with RCC, and the mean value of MVD CD31/CD105 was 31.68/20.66. The immunohistochemical expression of VEGF does not correlate with MVD performed on slides stained for both CD31 and endoglin. The majority of blood vessels in the tumor area are of mature type, with perivascular cells positive for SMA.