Guillermo Velasco in 2009 at Complutense University in Spain has found that the active ingredient in marijuana, Tetrahydrocannabinol, causes brain cancer cells to undergo a process called Autophagy. Autophagy is when a cell breaks down and dies due to it cannibalizing itself.
Velasco's team administered THC to mice with human brain cancer cells and two people with brain tumors. The mice that received the THC caused their tumors to shrink tremendously. The two human patients received THC as an experimental treatment for a highly aggressive brain tumor called Recurrent Glioblastoma Multiforme. Biopsies of the tumor were taken before and after treatment to track its progress. After receiving the THC, the tumor showed increased autophagy activity. The human trial used a 30-day THC treatment regimen, where the researchers found that THC eliminated cancer cells while it left healthy cells intact. Velasco noted that it appears “to kill cancer cells, while it does not affect normal cells.”
The patients receiving this treatment did not have any toxic effects from the THC. Guillermo Velasco's findings appear in the April 1, 2009 issue of the Journal of Clinical Investigation. He says his findings could lead to new strategies for preventing tumor growth. “These results may help to design new cancer therapies based on the use of medicines containing the active principle of marijuana and/or in the activation of autophagy,” Velasco said.