KDR and breast cancer: In breast cancer patients, downregulation of angiotensin-converting enzyme 2 (ACE2) checked the expression of VEGF-A and deactivated the phosphorylation of VEGFR2, MEK1/2, and ERK1/2 in human umbilical vessel endothelial cells (HUVECs), thereby inhibiting angiogenesis through the VEGF-A/VEGFR-2/ERK pathway (37).