Breast cancer therapy boost

AN IRISH research team has found a way to switch off a patient’s resistance to breast cancer treatments. The findings may also help spot women likely to develop resistance to the most often used therapies.

The research group at the Education and Research Centre at St Vincent’s University Hospital in Dublin is trying to develop a way to treat women with HER2-positive breast cancer. These patients, about one in five breast cancer cases, are resistant to treatment using Trastuzumab, better know as Herceptin, explained team leader Dr Patricia McGowan.

She is an Irish Cancer Society research fellow and received €230,000 from the society to pursue the research. She in turn is part of a wider research group headed by Prof Joe Duffy.

While HER2-positive patients tend to respond well to Herceptin and chemotherapy initially, the cancer develops resistance to the therapy over time, Dr McGowan said.

Her research project involves targeting a protein called Notch, a substance known to support the growth of cancer cells.

The team used cancer cell cultures to test a mix of already available drugs that when combined were able to interfere with the Notch protein, suppressing its activity.

The drugs effectively switched the protein off and may block other pathways used by the cancer cells to develop resistance, Dr McGowan said.

“Our results also apply to resistance to certain chemotherapies and other drugs and so there are a number of different avenues that we are exploring at the moment,” Dr McGowan said.

The initial findings were “good news” for those with HER2-positive breast cancer, she said.

Dr McGowan cautioned that the research did not represent a treatment yet. “It is very early stages,” she said, and it could be five years or more before the results can be confirmed and treatments tested.

“We need to find out exactly how these drugs work and how long they will work,” Dr McGowan said.

About 500 women are diagnosed with HER2-positive breast cancer here each year. The preliminary results suggest that those who develop resistance may still be successfully treated by blocking the Notch protein.

The work should also yield a way to diagnose those likely to become resistant to the therapy.

The Irish Cancer Society provided €700,000 in funding for breast cancer research during 2011, according to the society’s head of research, Prof John Fitzpatrick.