Another phase III trials, PENELOPE-B (NCT01864746), is designed to demonstrate that in the background of standard anti-hormonal therapy palbociclib provides superior invasive disease-free survival (iDFS) compared to placebo in premenopausal and postmenopausal women with HR-positive, HER2-normal early breast cancer at high risk of relapse after showing less than pathological complete response to neoadjuvant taxane-containing chemotherapy. This evidence concerns the gene ERBB2 and breast cancer.