The relatively higher use of PARP inhibitors in the TNBC subgroup compared with the HR+/HER2-negative subgroup likely reflects that there are limited nonchemotherapy treatment options for patients with triple-negative disease, whereas patients with HR+/HER2-negative ABC have other nonchemotherapy-targeted treatment options, such as CDK4/6 inhibitors, PIK3CA inhibitors, and mTOR inhibitors, combined with endocrine therapy that can be utilized in the second and third lines. This evidence concerns the gene CDK4 and aneurysmal bone cyst.