Nature Med. doi:10.1038/nm.2186 (2010)

Growing tumours rely on a good blood supply to feed them, so the identification of a small RNA molecule that switches on blood-vessel growth in tumours provides a potential target for anti-cancer drugs.

Small regulatory RNAs called microRNAs are known to regulate vascular development. To find microRNAs that initiate this process in tumours, David Cheresh at the University of California, San Diego, and his colleagues looked for microRNAs in human embryonic stem-cell models of blood vessel development. One, called miR-132, was highly expressed in human tumour vasculature, but not in normal tissue.

The microRNA boosted the growth of human blood vessel cells in culture, whereas reducing miR-132 expression in mice stunted blood vessel growth and shrank transplanted human breast tumours. The molecule turns on vascularization by suppressing RASA1, a protein that inhibits blood vessel development.