Genes for breast cancer spread found

Mon May 11th, 2009

By Jane Collingwood
Experts have identified three genes that are involved when breast cancer spreads to the brain.

Dr Joan Massague and colleagues at Memorial Sloan-Kettering Cancer Centre, New York, USA, found that the genes COX2 and HB-EGF encourage the movement and invasiveness of cancer cells, and mediate the metastasis of breast cancer cells across the blood-brain barrier.

This barrier normally prevents the entry of cells circulating in the bloodstream and regulates the movement of molecules into brain tissue.

The experts also say that a third gene, ST6GALNAC5, "provides cancer cells with the capability of exiting the blood circulation and entering the brain tissue".

In the journal Nature, the authors explain that the molecular basis for breast cancer metastasis to the brain is largely unknown, but "brain relapse typically occurs years after the removal of a breast tumour, suggesting that disseminated cancer cells must acquire specialised functions to take over this organ".

Using gene expression profiling they examined cells taken from patients with advanced disease, to identify the three genes as "mediators of cancer cell passage through the blood-brain barrier".

Whereas COX2 and HB-EGF have been linked to breast cancer spread to the lungs, ST6GALNAC5 specifically mediates brain metastasis, and is normally only expressed in the brain.

Dr Massague said: "Our research sheds light on the role these genes play in determining how breast tumour cells break free and, once mobile, how they decide where to attack.

"Our results draw attention to the role of the cell surface coating as a previously unrecognised participant in brain metastasis, and to the possibility of using drugs to disrupt its interactions," he added.

Bos, P. D. et al. Genes that mediate breast cancer metastasis to the brain. Nature, published online May 6, 2009.

Tags: Women’s Health & Gynaecology | North America | Cancer | Genetics