Stockholm breast cancer discovery could improve care

Researchers from Sweden say that a handful of genes can determine how patients respond to breast cancer therapy, opening the door to methods that could make treatment more effective.

In an article in the current issue of Breast Cancer Analysis, scientists at Stockholm’s Karolinksa Institute say that using DNA microarray technology that focuses on particular genes could help predict a breast cancer patient’s potential response to therapy. This genetic information could be used to tailor make therapy to prevent patients from having to endure painful, unsuccessful therapies, the researchers argue.

They identified a group of 64 genes that can be used to predict a breast cancer patient’s five-year response to adjuvant therapy, which is the additional treatment given to lower the chance of a cancer coming back.

They used so-called microarray analysis to examine the gene expression profiles in tumour tissue samples from 159 patients. Microarray analysis permits scientists to detect thousands of genes in a small sample simultaneously and to analyze the expression of those genes.

Of these 159 patients, 38 had a poor prognosis; relapse or death from any cause within five years. The study found that using the expression patterns of the 64 genes gave much better prediction rates than histological grading, tumour stage and age, all accepted prognostic indicators for breast cancer.

Identifying patients whose breast tumours express these genes could potentially be used to predict which patients would not benefit from adjuvant therapy, and avoid patients being given therapies with the potential of causing more harm than good.

The present lack of criteria to help tailor breast cancer treatment to individual patients indicates a need to develop new techniques for better prediction of how patients will respond to adjuvant treatments. The team of researchers was led by Jonas Bergh, Professor in Clinical and Molecular Oncology at the Karolinska Institute.

The remaining 121 patients were defined as the ‘good prognosis’ group. The researchers also used gene expression profiling to separate patients who did well with and without adjuvant therapy, and those whose tumours failed to respond to treatment.