Epigenetic study explains differences in response to breast cancer treatment

Kathleen Blanchard's picture
Breast cancer DNA methylation types

Researchers discover how epigenetics influences response to breast cancer treatment.

The scientists note the importance of the study. They looked at estrogen positive and estrogen negative breast cancer types, finding distinctly different DNA methylation profiles in the subgroups of breast cancer, both of which are epigenetically controlled.

The study investigators, from the European Society of Medical Oncology, explain methylation is a chemical modification that takes place within DNA. Epigenetics is the term used to describe those modifications.

Dr Sarah Dedeurwaerder, from Université Libre de Bruxelles, in Brussels, explained the findings at the IMPAKT Breast Cancer Conference.

Dr Dedeurwaerder said. “Indeed, several patients displaying the same known sub-type of breast cancer can respond differently to a given drug. An epigenetic difference between the tumors of these patients might explain the difference observed in terms of treatment response. Therefore, DNA methylation profiling could help to refine the current breast cancer classification and thus might help to stratify patients within a particular sub-type both in terms of prognosis and prediction to treatment response.”

DNA methylation differs in same breast cancer types


For the study, the researchers first looked at the type of breast cancer, sorting tumors as estrogen positive or negative. Next they looked at DNA methylation profiles, finding a “reverse correlation between methylation and expression status of the majority of these genes”, explained Dedeurwaerder.

The findings could improve breast cancer treatment. Dedeurwaerder says DNA methylation markers can be profiled from analysis of body fluids, helping diagnose breast cancer sooner. She also says understanding which markers are present can predict breast cancer treatment response and outcomes.

“Lastly, an epigenetic therapy of cancer, alone or in combination with conventional therapies, is conceivable. Indeed, several drugs have been developed and several clinical trials have already shown promising results, in particular for leukemia.”

The finding explains differences breast cancer outcomes among women receiving the same treatment and lays the groundwork for personalizing care of women with the disease.

The study is the largest analysis of epigenetic breast cancer changes. In the study, the researchers looked at 400 genes to find very different methylation profiles in women with the same type of breast cancer.