Scientists discover why some breast cancers are drug resistant

Feb 13 2008

Research by British scientists has revealed how cancer cells which have a faulty gene can become resistant to treatment.

In a new study funded by Breakthrough Breast Cancer and Cancer Research UK, researchers examined cancer cells which contained a faulty version of the gene BRCA2.

Women who inherit this faulty gene are at a much higher risk of developing breast and ovarian cancer.

BRCA2 is involved in repairing damaged DNA but cells containing faults in this gene accumulate even more genetic damage as they grow and multiply.

It is this feature which renders them extremely sensitive to cancer drugs that damage DNA, such as PARP inhibitors and carboplatin; BRCA2 cancers can become resistant to these therapies very quickly and is one of the main reasons why treatment fails.

When the research team examined the condition of the BRCA2 gene in cells that had become resistant, they found that the BRCA2 gene had re-activated itself and this in turn allowed the cancer to repair its damaged DNA and survive.

The researchers believe their discovery could lead to new treatments that make resistant cancer cells sensitive to treatment once more.

Professor Alan Ashworth from Breakthrough Breast Cancer says this genetic mechanism allows cancer cells to survive by changing the way treatments affect them.

Professor Herbie Newell, the executive director of translational research for Cancer Research UK, says drug resistance is a problem common to all types of cancer which is poorly understood and by understanding this process patient treatment can altered to counteract the problem of resistance.

The researchers believe this particular mechanism of resistance might be a common way by which many other types of cancer become resistant to treatment.

The Breakthrough Breast Cancer Research Centre at The Institute of Cancer Research is Europe's leading cancer research centre.