The Little Brown Reader

The study by Manuel Guzmán of Madrid Spain found that cannabinoids, the active components of marijuana, inhibit tumor growth in laboratory animals. They do so by modulating key cell-signalling pathways, thereby inducing direct growth arrest and death of tumor cells, as well as by inhibiting the growth of blood vessels that supply the tumor.

The Guzman study is very important according to Dr. Ethan Russo , a neurologist and world authority on medical cannabis: "Cancer occurs because cells become immortalized; they fail to heed normal signals to turn off growth. A normal function of remodelling in the body requires that cells die on cue. This is called apoptosis, or programmed cell death. That process fails to work in tumors. THC promotes its reappearance so that gliomas, leukemias, melanomas and other cell types will in fact heed the signals, stop dividing, and die."