NTRK1 and cancer: Three different tyrosine kinase receptors of VEGF are VEGFR1 (Flt-1), VEGFR2 (Flk-1-KDR), and VEGFR3.[10] Upon binding to its receptors, activated VEGF family promotes proliferation of vascular cells to develop new blood vessels in tumor tissues, which, in turn, ensures oxygen and nutrients supply and causes cancer growth and metastasis.[9,11] Among the 3 VEGFRs, VEGFR2 plays a pivotal role in VEGF-mediated cancer angiogenesis.