The Deadly Cancer That Grows for Two Decades

This news could leave you gasping: Lung cancer—which kills more people than any other cancer—can develop slowly for 20 years before it becomes aggressive enough to detect, finds new research from University College London.

Scientists studied 25 regions of seven lung tumors surgically removed from patients. They found that certain genetic mutations occur early in a tumor’s development, probably as a result of carcinogen exposure, especially in smokers and ex-smokers. Later—likely years later—a DNA-editing protein called APOBEC mutates DNA within the tumor, and that’s when the cancer really starts to progress, says study author Elza De Bruin, Ph.D.