Palbociclib is a selective cyclin-dependent kinase (CDK) 4/6 inhibitor approved for use in postmenopausal women with hormone receptor-positive, human epidermal growth factor 2-negative (HR+/HER2-) advanced/metastatic breast cancer (ABC/MBC).
Dovitinib was then evaluated in a phase II trial that included 4 groups of patients with human EGF receptor 2-negative metastatic breast cancer on the basis of FGFR1 amplification and hormone receptor (HR) status.
High tumor levels of ER, PgR, AR and pS2 predict a relatively good response to endocrine therapy, while EGF-R positively, HER2/neu positivity, aneuploidy, high proliferation indices and possibly high uPA levels indicate a high chance of poor response to endocrine therapy in metastatic breast cancer.