Module 9: Figure angiogenesis
This figure depicts the growth of new vessels responding to vascular endothelial growth factor A (VEGF-A) released from a tumour. In the initial response (stages A–C), a single endothelial cell differentiates into a tip cell to initiate the growth of a sprout. As the endothelial cells (ECs) proliferate, this new sprout grows and new tip cells appear (stages D and E) to form a branch. The newly formed vessels then invade the tumour providing a new blood supply. See text for further details.