[Light-induced disruption of the circadian clock and risk of malignant tumors in laboratory animals: state of the problem].

There were obtained sufficient experimental evidence of the stimulating effect on the development of tumors (transplanted, spontaneous and induced by various carcinogenic agents), disorders of circadian function of the pineal gland (light-induced desynchronosis) caused by knockout or mutation of clock genes, pinealectomy, content in conditions of constant light or natural light regime of the North, as well as jetlag modeling in laboratory rodents. In experiments on various models of carcinogenesis it was found that sympathectomy (removal of the superior cervical ganglion), light deprivation, hibernation and application of melatonin, the natural hormone of the pineal gland, had an inhibitory effect on the development of transplanted, spontaneous and induced tumors of different histogenesis.