Chronically Alternating Light Cycles Increase Breast Cancer Risk in XXXX .

@entity1 @entity73158 @entity0 @entity28 @entity5 @entity899 @entity19 @entity2493 @entity1442 @entity25 @entity560
Although epidemiological studies in shift workers and flight attendants have associated chronic @entity1442 ( @entity1442 ) with @entity0 risk, causal evidence for this association is lacking. Several scenarios have been proposed to contribute to the shift work- @entity5 connection: (1) internal desynchronization, (2) light at night (resulting in @entity2493 suppression), (3) sleep disruption, (4) lifestyle disturbances, and (5) decreased @entity560 levels due to lack of sunlight. The confounders inherent in @entity1 field studies are less problematic in animal studies, which are therefore a good approach to assess the causal relation between circadian disturbance and @entity5 . However, the experimental conditions of many of these animal studies were far from the reality of @entity1 shift workers. For example, some involved xenografts (addressing @entity5 growth rather than @entity5 ), chemically induced @entity5 models, or continuous bright light exposure, which can lead to suppression of circadian rhythmicity. Here, we have exposed @entity0 -prone @entity899 ( @entity73158 /+)WAPCre conditional mutant @entity19 (in a FVB genetic background) to chronic @entity1442 by subjecting them to a weekly alternating light-dark (LD) cycle throughout their life. Animals exposed to the weekly LD inversions showed a decrease in @entity5 suppression. In addition, these animals showed an increase in body weight. Importantly, this study provides the first experimental proof that @entity1442 increases @entity0 development. Finally, our data suggest internal desynchronization and @entity25 as mechanisms linking shift work with @entity5 development and @entity28 .
