CALML5 and breast cancer: Misawa et al., 2020 reported that the methylation of CALML5 led to its downregulation, and this showed a correlation with HPV-associated oropharyngeal cancer. Moreover, the ubiquitination of CALML5 in the nucleus was found to play a role in the carcinogenesis of breast cancer in premenopausal women (Debald et al., 2013). Our results suggested that the high expression of CALML5 in HER2+HR+ breast cancer patients may lead to the resistant of pyrotinib combined with tamoxifen and the introduction of dalpiciclib might overcome this drug resistance and offer better therapeutic effects.