Circadian rhythms and breast cancer: from molecular level to therapeutic advancements.

BACKGROUND AND OBJECTIVES: Circadian rhythms, the endogenous biological clocks that govern physiological processes, have emerged as pivotal regulators in the development and progression of breast cancer. This comprehensive review delves into the intricate interplay between circadian disruption and breast tumorigenesis from multifaceted perspectives, encompassing biological rhythms, circadian gene regulation, tumor microenvironment dynamics, and genetic polymorphisms. METHODS AND RESULTS: Epidemiological evidence underscores the profound impact of external factors, such as night shift work, jet lag, dietary patterns, and exercise routines, on breast cancer risk and progression through the perturbation of circadian homeostasis. The review elucidates the distinct roles of key circadian genes, including CLOCK, BMAL1, PER, and CRY, in breast cancer biology, highlighting their therapeutic potential as molecular targets. Additionally, it investigates how circadian rhythm dysregulation shapes the tumor microenvironment, fostering epithelial-mesenchymal transition, chronic inflammation, and immunosuppression, thereby promoting tumor progression and metastasis. Furthermore, the review sheds light on the association between circadian gene polymorphisms and breast cancer susceptibility, paving the way for personalized risk assessment and tailored treatment strategies. CONCLUSIONS: Importantly, it explores innovative therapeutic modalities that harness circadian rhythms, including chronotherapy, melatonin administration, and traditional Chinese medicine interventions. Overall, this comprehensive review emphasizes the critical role of circadian rhythms in the pathogenesis of breast cancer and highlights the promising prospects for the development of circadian rhythm-based interventions to enhance treatment efficacy and improve patient outcomes.