Hence, with the rapid development of small-molecule drugs such as tyrosine kinase inhibitors (TKIs) and CDK4/6 inhibitors, additional chemo-free strategies are being developed for the treatment of HER2+/HR+ breast cancer (Gianni et al., 2018; Pascual et al., 2021; Saura et al., 2014). This evidence concerns the gene CDK4 and breast cancer.