Review of research on the relationship between circadian rhythms and carcinogenesis using animal models

Purpose of the study: to review in vivo studies on the relationship and role of various molecular genetic components of the circadian rhythm system in the initiation and development of malignant neoplasms. in contrast to clinical and epidemiological studies, animal models, including transgenic animal models, can model various changes and disturbances in the activity of clock genes and track the results of these changes. Material and Methods. The review includes data from studies carried out over the past 10 years in animal models, studying the mechanisms and effects of disturbances in the system of circadian rhythms related to the formation and development of tumors. The data sources for the review were the Medline, Embase and Scopus databases. Results. Analysis of the literature has shown that interference with the work of the «biological clock» by changing the light cycle, disrupting the expression of clock genes and other manipulations is a factor predisposing to the development of tumors. in tumors of various types, the expression of clock genes is often mismatched, and it is unclear at what stage of their formation this occurs. in addition, the development of tumors disrupts the circadian homeostasis of the body. There are three key areas of research aimed at studying the role of circadian rhythms in tumor development: disturbance of circadian rhythms as a carcinogenic factor, disturbances in the clock gene system in a tumor, disturbances in the clock gene system of the whole organism, provoked by tumor development. Conclusion. The results of studies on animal models demonstrate that the relationship between the disturbance of circadian rhythms and the tumor process is complex since the causal relationship has not yet been studied. in this regard, the prospect of targeted pharmacological correction of circadian rhythms in clinical practice in cancer patients does not seem to be the nearest one.