Clock genes vs. Breast cancer

Abstract

Clock genes (C G) are responsible for adapting body to diurnal changes in environmental conditions (circadian cycles, C C) . Discordances caused by changes in both environmental CC (shift work, excess light at night, or jet lag) and bodily C C, in particular due to changes in CG expression, increase the risk of cancer, the breast being the most vulnerable site. The present discussion is based on the reviews of relevant epidemiological and experimental findings, including meta-analyses, mainly published within the last five years. The conclusions related to translational medicine are, with regard to prevention, that shift work is a significant risk factor of breast cancer and, with regard to treatment, that melatonin properties make it feasible to develop regimens of its administration able to synchronize tumor and body CC so that cancer becomes most sensitive to treatment when body is least vulnerable to its side effects.