Thymidine phosphorylase is angiogenic growth factor which promotes angiogenesis in vivo and stimulates the in vitro growth of a variety of endothelial cells. Thymidine phosphorylase has a highly restricted target cell specificity acting only on endothelial cells, hence its alternative name of ECGF1. Because it limits glial cell proliferation, thymidine phosphorylase is also known as gliostatin. Thymidine phosphorylase activity in leukocytes from mitochondrial neurogastrointestinal encephalomyopathy (MNGIE) patients was less than 5 percent of controls, indicating that loss-of-function mutations in TYMP cause MNGIE.
