Dr. O’Regan on Biomarkers of Response to CDK4/6 Inhibitors in Breast Cancer

Ruth O’Regan, MD, professor, division head, Hematology and Oncology, Department of Medicine, University of Wisconsin School of Medicine and Public Health, associate director, Clinical Research, University of Wisconsin Carbone Cancer Center, discusses biomarkers of response to CDK4/6 inhibitors in breast cancer.

Extensive research regarding potential biomarkers of response to CDK4/6 inhibitors has been done in breast cancer, says O’Regan. Despite looking at proteins involved in the retinoblastoma pathway and the CDK4/6 pathways, researchers have not been able to validate a biomarker of response apart from the estrogen receptor (ER).

Moreover, emerging evidence suggests that cancers that are ER negative may benefit from CDK4/6 inhibitors, says O’Regan. However, more research is needed to determine exactly which subtypes benefit the most as well as understand the nuances of response in the early and metastatic settings, concludes O’Regan.