The anti-angiogenic drugs currently used in cancer therapy target the proliferating tumor ECs by two major mechanisms: neutralizing angiogenic factors or their receptors by using macromolecule anti-angiogenic drugs (e.g., therapeutic antibodies) or blocking the receptor tyrosine kinases intracellularly with small molecule (Mr < 1 kDa) receptor tyrosine kinase inhibitors (RTKIs) bound to albumin [12]. This evidence concerns the gene NTRK1 and cancer.