FIGURE 2.

Endothelial fenestrations on microvasculature from VHL mutant clear cell renal cell carcinoma (ccRCC) might be vascular endothelial growth factor‐dependent and sensitive to bevacizumab. (A) Electron micrographs of tumor capillaries in VHL WT ccRCC and VHL mutated ccRCC. Representative data are shown. Capillaries from tumors with mutant VHL exhibit endothelium with more abundant endothelial fenestration (EFs) compared with those with WT VHL. SEM, scanning electron microscope. (B) Quantification of EFs in tumor capillaries with or without VHL mutation. The numbers of EFs were calculated per square micrometer. (C) Electron micrographs of tumor capillaries in xenografts from WT8 and pRC3 cells. Representative data are shown. Capillaries from VHL ^−/− pRC3 xenografts exhibited abundant EFs. (D) Electron micrographs show a reduction of EFs in VHL ^−/− pRC3 xenografts by the bevacizumab (BEV) treatment. CTR, control.