Circadian clock and cancer therapy: an unexpected journey.

Chronotherapy of cancer is one of the oldest examples of the clinical application of biological rhythms. Growing understanding of the importance of biological timing in physiology and pathophysiology of many diseases including cancer reforms our views on the role of biological clocks in cancer and cancer treatment. In the present issue the current progress in circadian clock-dependent mechanisms of cancer, polymorphism and mutations of clock gene in cancer, cancer-associated clock disruptions, and novel chronotherapeutic approaches are discussed.