Bright Lights, Big Cancer

Melatonin-depleted blood spurs tumor growth

In late 1987, Richard G. Stevens, then at Pacific Northwest Laboratories in Richland, Wash., typed up a short letter and mailed it to Walter Willett at Harvard Medical School in Boston. The two epidemiologists had met just once, and Stevens wasn’t confident that his 209-word note, or the suggestion that it contained about a possible contributor to breast cancer, would inspire any action.