They occur due to a malfunction of proteins that repair DNA damage in normal body cells. (sciencedaily.com)
Carlo Croce, a cancer researcher at Ohio State University in Columbus, and his colleagues created a diagram of interacting miRNAs for normal body cells by connecting them according to which genes they target and the function of those genes, in a way similar to analyses of human social networks. (newscientist.com)
Tumors go mostly unmolested by the body's natural defenses, partly because cancer cells are descendents of normal body cells. (sciencemag.org)