Previous studies from Holash [97] and Gale [88] aimed to understand the mechanism based on the enrolment of cancer cells along pre-existing vessels, showing how tumour cell migration towards perivascular sites is related to the expression of pro- and anti-angiogenic endothelial growth factors, for example, angiopoietin-1 and 2 (ANGPT-1, ANGPT-2) and VEGF. This evidence concerns the gene VEGFA and neoplasm.