Total darkness at night key to success of breast cancer therapy
Exposure to light at night, which shuts off nighttime production of the hormone melatonin, renders breast cancer completely resistant to tamoxifen, a widely used breast cancer drug, says a new study by Tulane University School of Medicine cancer researchers. The study, “Circadian and Melatonin Disruption by Exposure to Light at Night Drives Intrinsic Resistance to Tamoxifen Therapy in Breast Cancer,” published in the journal Cancer Research, is the first to show that melatonin is vital to the success of tamoxifen in treating breast cancer!
"High melatonin levels at night put breast cancer cells to ‘sleep’ by turning off key growth mechanisms. These cells are vulnerable to tamoxifen. But when the lights are on and melatonin is suppressed, breast cancer cells ‘wake up’ and ignore tamoxifen," Blask says.
Robert T. Dauchy et al. Circadian and Melatonin Disruption by Exposure to Light at Night Drives Intrinsic Resistance to Tamoxifen Therapy in Breast Cancer. Cancer Research, July 2014 DOI: 10.1158/0008-5472.CAN-13-3156