Notably, data have been provided indicating that the addition of bevacizumab to chemotherapy determines a clinical benefit only in right-sided tumors 16 and that RCC, but not LCC, is endowed with a pro-angiogenic microenvironment characterized by increased expression of endothelial nitric oxide synthase (eNOS), COX2, and ephrin type‐B receptor 4 (EPHB4) 52. This evidence concerns the gene EPHB4 and leukoencephalopathy with calcifications and cysts.