Abstract: The regulatory mechanism of cell cycle plays an important role in the occurrence and development of tumors. In recent years, a number of studies have shown that cyclin-dependent kinase 4/6 (CDK4/6) inhibitors have good efficacy in patients with estrogen receptor-positive, human epidermal growth factor receptor-negative breast cancer, but their efficacy in patients with triple-negative breast cancer is still controversial. Cyclin D-CDK4/6 -INK4-Rb-E2F signaling pathway is considered as a potential therapeutic target for breast cancer due to its role in regulating cell cycle check points. It is of great significance to explore the molecular markers related to CDK4/6 inhibitors for triple-negative breast cancer, guide rational drug combination, and screen the population of triple-negative breast cancer patient who can benefit from this drug. In this article, we reviewed the research progress of CDK4/6 inhibitors in triple-negative breast cancer, and discussed their application prospects and optimization methods.

Key words: Cyclin-dependent kinase 4/6, Cyclin D/E, Triple-negative breast cancer, Retinoblastoma protein, Androgen receptor