Why working the night shift can pose a cancer risk
A handful of large studies of cancer risk factors have found that working the night shift, as nearly 15 percent of Americans do, boosts the chances of developing cancer. MIT biologists have now found a link that may explain this heightened risk. In humans and most other organisms, a circadian clock governed by light regulates the timing of key aspects of human physiology, by controlling cellular activities such as metabolism and division. In a study of mice, the MIT team found that two of the genes that control cells’ circadian rhythms also function as tumor suppressors. Loss of these tumor suppressors, either through gene deletion or disruption of the normal light/dark cycle, allows tumors to become more aggressive. “It doesn’t matter how you disrupt the clock — both ways, loss of it seems to drive tumorigenesis,” says Thales Papagiannakopoulos, a former postdoc at MIT’s Koch Institute for Integrative Cancer Research and the lead...