New laboratory findings at the University of Illinois at Chicago suggest that what lies outside cancer cells is at least as important as the genes inside in explaining a tumor’s malignancy. The molecules that surround a cell play a crucial role in altering the packaging of its genome, opening it up to the machinery that allows genes to be expressed, or closing it down, according to a study published in the April issue of the American Journal of Pathology. An editorial in the same issue of the journal says the study represents what it calls a paradigm shift in our understanding of how malignant cells operate. The findings are expected to yield new diagnostic and therapeutic tools in the battle against cancer. Initial experiments at UIC found that the genetic material of cancer cells is knotted-up so that sections of DNA are highly protected from outside interference, unlike the DNA of healthy tissue. An enzyme that snips DNA at certain sequences that recur throughout the genome thoroughly chewed up the DNA from normal cells. In contrast, the enzyme only partially broke up the DNA from less aggressive tumors, and it barely touched the DNA from aggressive cancers like melanoma.
