Although benefit from the addition of palbociclib to endocrine therapy seems particularly relevant in patients with sensitivity to endocrine therapy[30] (which certainly our patient has), the long-term disease control obtained in this case with endocrine therapy alone questions the need for using CDK4/6 inhibitors in all patients with HR-positive advanced breast cancer, highlighting the need to better study predictors of treatment benefit. This evidence concerns the gene CDK4 and breast carcinoma.