In addition, CDK4/cyclin D inhibition may be additionally beneficial for the treatment of human epidermal growth factor receptor 2 (HER2) and RAS‐driven breast cancers (Yu et al, 2001; Goel et al, 2016) and potentially many other cancers because cyclin D1 displays most frequent somatic copy number aberrations of all cancer genes (Leiserson et al, 2015). Here, ERBB2 is linked to breast cancer.