Tumours rely on the blood vessels that permeate them to survive. However, secretions from the endothelial-cell lining that supports these vessels blunt tumour growth and spread.

Elazer Edelman at the Massachusetts Institute of Technology in Cambridge and his colleagues studied the effect of endothelial cells, which are abundant in tumours, on human breast- and lung-cancer cells. Those grown in media previously occupied by human endothelial cells exhibited a 40% reduction in growth and were also less invasive. Knocking down a key protein expressed by endothelial cells lowered their ability to block tumour invasion.

Similar anti-tumour effects were seen when the endothelial cells were implanted in mice.

Sci. Transl. Med. 3, 66ra5 (2011)