CDK4/6 Inhibitor Biomarker Research: Are We Barking Up the Wrong Tree?

CDK4/6 inhibitors have emerged as a significant advance for the treatment of patients with advanced estrogen receptor–positive breast cancer. However, the identification of predictive markers that optimize their use is proving harder than expected. In this commentary we advocate for unbiased discovery and a collaborative approach across trials. See related article by Finn et al., p. 110