Breast cancer biomarkers may guide immune-response therapies

New biomarkers for breast cancer outcomes and response to treatment have been presented at the 4th IMPAKT Breast Cancer Conference in Brussels. In a study led by Institut Jules Bordet in Brussels, a team of researchers looked at gene expression data, focusing on groups of genes, from a number of studies of women treated with anthracyclines before surgery, with or without taxane chemotherapy. The groups of genes, or gene modules, had already been linked with tumor growth or immune response to the cancer. The analysis found that the breast tumors expressing high levels of immune response genes were more likely to be destroyed by the chemotherapy than those with low expression, and this was more common in HER2-positive cancers. This finding could help to select those patients most likely to respond to drugs that target the immune response.

"The role of agents that modulate immune response in breast cancer should be studied, and in these trials patients should be optimally stratified based on their immune response," said Dr. Michail Ignatiadis from Institut Jules Bordet. "Moreover, future studies should investigate whether the efficacy of anti-HER2 agents in HER2-positive early breast cancer patients is also associated with tumor immune response."

A second study at the same conference could lead to a biomarker to identify those patients who could benefit the most from everolimus, a treatment that suppresses the immune system. Everolimus is already used in renal cell cancer, and is being studied in other cancers, including breast cancer.

In the study, led from the Centre Leon Berard in Lyon, France, a team analyzed data from the TAMRAD study, which compared everolimus and tamoxifen with tamoxifen alone. The study showed that adding in everolimus delayed cancer progression in some patients, and the researchers found that women who had low levels of phosphatidylinositol 3-kinases (PI3Ks), enzymes that are involved in cell growth and proliferation, and low levels of a protein called LKB1 were more likely to respond.

More research is needed, but this biomarker could help select those patients who might respond to the addition of everolimus, improving their quality of life and avoiding extra treatment for women who were unlikely to improve. Dr. Thomas Bachelot, from Centre Leon Berard explained: "This is of great importance, as everolimus is quite toxic and you don't want to give this drug if you're not sure the patient will benefit from it."

- read the press release on immune response genes
- see the press release on immunosuppressant treatment