Editing Angiogenesis (section)

===Formation of tumor blood vessels===
The mechanism of blood vessel formation by angiogenesis is initiated by the spontaneous dividing of tumor cells due to a mutation. Angiogenic stimulators are then released by the tumor cells. These then travel to already established, nearby blood vessels and activates their endothelial cell receptors. This induces a release of [[proteolytic]] enzymes from the vasculature. These enzymes target a particular point on the blood vessel and cause a pore to form. This is the point where the new blood vessel will grow from. The reason tumour cells need a blood supply is because they cannot grow any more than 2-3 millimeters in diameter without an established blood supply which is equivalent to about 50-100 cells.<ref>{{cite journal | vauthors = Nishida N, Yano H, Nishida T, Kamura T, Kojiro M | title = Angiogenesis in cancer | journal = Vascular Health and Risk Management | volume = 2 | issue = 3 | pages = 213–219 | date = September 2006 | pmid = 17326328 | pmc = 1993983 | doi = 10.2147/vhrm.2006.2.3.213 | doi-access = free }}</ref> Certain studies have indicated that vessels formed inside the tumor tissue are of higher irregularity and bigger in size, which is as well associated with poorer prognosis.<ref>{{cite journal | vauthors = Milosevic V, Edelmann RJ, Winge I, Strell C, Mezheyeuski A, Knutsvik G, Askeland C, Wik E, Akslen LA, Östman A | display-authors = 6 | title = Vessel size as a marker of survival in estrogen receptor positive breast cancer | journal = Breast Cancer Research and Treatment | volume = 200 | issue = 2 | pages = 293–304 | date = July 2023 | pmid = 37222874 | pmc = 10241708 | doi = 10.1007/s10549-023-06974-4 }}</ref><ref>{{cite journal | vauthors = Mikalsen LT, Dhakal HP, Bruland ØS, Naume B, Borgen E, Nesland JM, Olsen DR | title = The clinical impact of mean vessel size and solidity in breast carcinoma patients | journal = PLOS ONE | volume = 8 | issue = 10 | pages = e75954 | date = 2013-10-11 | pmid = 24146798 | pmc = 3795733 | doi = 10.1371/journal.pone.0075954 | bibcode = 2013PLoSO...875954M | doi-access = free | veditors = Aoki I }}</ref>