Immunohistochemical staining of mTOR, vascular endothelial growth factor, CD34 and microvascular density in clear cell renal cell carcinoma and its correlation with clinicopathological profile of the tumour

Abstract

Background: The study analyses immunoexpression of vascular endothelial growth factor (VEGF) and mammalian target of rapamycin (mTOR) based pathways which are mainstay of drug therapy in advanced and metastatic clear cell renal cell carcinoma (ccRCC) and to delineate their role as prognostic markers in a cohort of primary ccRCC. Methods: Descriptive study wherein immunohistochemical profiling of 100 cases of primary ccRCC was carried out using primary antibodies against mTOR, VEGF and CD34. Mean vascular density (MVD) and immunoreactivity was correlated with grading, staging, risk stratification and survival data. Results: mTOR and VEGF immunostaining was positive in 54% and 70% cases respectively with strong immunoreactivity correlating with high grade, high stage and high risk tumours with low survival. Inverse association was observed with MVD wherein low grade, low stage and low risk ccRCCs were associated with higher MVD. Conclusion: mTOR and VEGF expression in ccRCCs is associated with unfavourable prognosis. High MVD correlates with better outcome though concordance is limited by tumour heterogeneity.