We used Bafilomycin A1, a specific inhibitor of V-ATPase, to block lysosomal acidification/activation under normoxic conditions and observed that EGF-induced EGFR degradation was reduced in cultured endothelial cells, as well as epithelial tumor cell lines after ligand stimulation, as seen in hypoxic conditions (Figure 1B). Here, EGFR is linked to neoplasm.