Study says THC reduces cancer risk
In an interview with Reuters, Melamede explained that while nicotine has several effects that promote lung and other types of cancer, THC acts in ways that counters the cancer-causing chemicals in marijuana smoke. "THC turns down the carcinogenic potential," he said. Melamede reviewed the scientific evidence in a recent issue of Harm Reduction Journal.
Lab research indicates that nicotine activates an enzyme in the body that converts certain chemicals in both tobacco and marijuana smoke into cancer-promoting form. But studies in mice suggest that THC blocks this enzyme activity.