CDK4 and aneurysmal bone cyst: The combination of ET with cyclin-dependent kinase 4/6 (CDK4/6) inhibitors has resulted in prolonged clinical benefit in patients with HR+, human epidermal growth factor receptor 2-negative (HER2−) ABC, and is now the recommended first-line treatment for these patients as per the ESO-ESMO and NCCN guidelines [10,11].