Circadian Cycle and Chronotherapy: Role in the Treatment of Various Biological Disorders

Circadian clocks can be defined as endogenous molecular time-keeping systems that are involved in triggering daily fluctuations in various physiological and biochemical processes. Since early times, the circadian clock has been pragmatic in behavioral and physiological patterns in plants and animals. The circadian clock in humans has a genetic background and many circadian genes have been identified. Important functions of our body such as sleeping, hormone production, digestive secretion and immune activity take place under the influence of the circadian clock in such a way that they occur at times that are most energetically favorable to us. Many studies have suggested that the dysfunction of the circadian system may be associated with an increased incidence of cancer. Cancer chronotherapy is one of the latest developments in the treatment and management of cancer patients. The foundation of cancer chronotherapy lies in utilizing the body's own circadian (Biological) clock to help the patient maximise the efficacy of their treatment. This brief review substantiates the important role played by circadian clocks in the development and the therapeutic efficacy of anticancer agents.