Medical scientists at the University of Leicester have announced a potentially unique advance in breast cancer research by identifying two genes associated with adverse reaction to cancer treatment.

The research could mean people who might react badly to radiotherapy could be warned in advance or alternative treatments be sought. There is no test at present for an abnormal reaction to radiotherapy. No-one in the past has proposed such a test.

The team who carried out the study included Drs Paul Symonds, Mark Plumb, Irene Peat and George Giotopoulos of the Department of Cancer Studies and Molecular Medicine and the Department of Genetics at the University of Leicester. Their results are published in the British Journal of Cancer.

Dr Symonds said: "Radiotherapy is a very important treatment for breast cancer. A small number of people can develop severe side effects."

"During treatment patients can get redness of the skin which may peel off. Later the breast may shrink (atrophy) and the tissues under the skin may become hard and thickened (fibrosis). Red widened blood vessels can appear in the skin (telangiectasia)."

After examining patients at the Glenfield Hospital, Leicester Royal Infirmary and the City Hospital Nottingham, the team at the University of Leicester, funded in part by the Hope Foundation for Cancer Research, has found 2 separate genes strongly associated with either thickening of tissue or red widened blood vessels.

"About 8% of women carry the fibrosis gene and have 15 times the risk of developing thickening of the tissues which is often associated with lifelong chronic pain.

"The genes we have identified at present have a predictive value of 50-60% for the development of marked fibrosis with breast pain. If we could identify the acute genes that lead to marked redness and peeling of the skin, this could increase the predictive value of the test to almost 100%."