HR and breast cancer: The role of some of those hub genes that we identified in our study has been verified in breast cancer, such as UBE2C whose overexpression plays a critical role in the incidence and development of breast cancer, and such a therapeutic strategy that combines palbociclib with tamoxifen might be promising in patients with HR+/HER2-breast cancer overexpressing UBE2C (Mo et al., 2017; Kim et al., 2019).