Cannabinoids, the active components of cannabis, have been shown to exhibit anti-tumor properties. Multiple studies have found that cannabinoids inhibit tumor growth in laboratory animals. In other studies, injections of synthetic THC eradicated malignant brain tumors in one-third of treated rats, and prolonged life in another third by as much as six weeks.
Italian research teams reported that the endocannabinoid anandamide, which binds to the same brain receptors as cannabis, "potently and selectively inhibits the proliferation of human breast cancer cells in vitro" by interfering with their DNA production cycle. Cannabis has been shown in recent studies to inhibit the growth of thyroid, prostate and colorectal cancer cells. THC has been found to cause the death of glioma cells. And research on pituitary cancers shows cannabinoids are key to regulating human pituitary hormone secretion.
More recently, investigators at the California Pacific Medical Center Research Institute reported that the administration of THC on human glioblastoma multiforme cell lines decreased the proliferation of malignant cells and induced apoptosis (programmed cell death) more rapidly than did the administration of an alternative synthetic cannabis receptor agonist.