Cookies on this website

We use cookies to ensure that we give you the best experience on our website. If you click 'Accept all cookies' we'll assume that you are happy to receive all cookies and you won't see this message again. If you click 'Reject all non-essential cookies' only necessary cookies providing core functionality such as security, network management, and accessibility will be enabled. Click 'Find out more' for information on how to change your cookie settings.

Platelet-derived endothelial cell growth factor was previously identified as the sole angiogenic activity present in platelets; it is now known to be thymidine phosphorylase (TP). The effect of TP on [methyl-3H]thymidine uptake does not arise from de novo DNA synthesis and the molecule is not a growth factor. Despite this, TP is strongly angiogenic in a rat sponge and freeze-injured skin graft model. Neutralizing antibodies and site-directed mutagenesis confirmed that the enzyme activity of TP is a condition for its angiogenic activity. The level of TP was found to be elevated in human breast tumors compared to normal breast tissue (P < 0.001). Overexpression of TP in MCF-7 breast carcinoma cells had no effect on growth in vitro but markedly enhanced tumor growth in vivo. These data and the correlation of expression in tumors with malignancy identify TP as a target for antitumor strategies.


Journal article


Proc Natl Acad Sci U S A

Publication Date





998 - 1002


Animals, Breast Neoplasms, Cattle, Cell Division, Cells, Cultured, Chemotaxis, Endothelium, Vascular, Female, Humans, Male, Mice, Mice, Inbred BALB C, Mutation, Neovascularization, Pathologic, Rats, Rats, Wistar, Substrate Specificity, Thymidine Phosphorylase