Guillermo Velasco and colleagues, at Complutense University, Spain, have provided evidence that suggests that cannabinoids such as the main active component of marijuana (THC) have anticancer effects on human brain cancer cells.

In the study, THC was found to induce the death of various human brain cancer cell lines and primary cultured human brain cancer cells by a process known as autophagy. Consistent with the in vitro data, administration of THC to mice with human tumors decreased tumor growth and induced the tumor cells to undergo autophagy. As analysis of tumors from two patients with recurrent glioblastoma multiforme (a highly aggressive brain tumor) receiving intracranial THC administration showed signs of autophagy, the authors suggest that cannabinoid administration may provide a new approach to targeting human cancers.