Breast cancer. Scientists at Pacific Medical Centers in San Francisco found that THC and other plant cannabinoids inhibited human breast cancer proliferation and metastasis and shrank breast cancer tumors. 1.3 million worldwide are diagnosed yearly with breast cancer and a half a million succumb to the disease (347).

Cannabidiol (CBD) reduces human breast cancer cell proliferation, invasion, and metastasis. Best results were obtained when CBD was utilized in conjunction with THC... [further] CBD strengthened the inhibitory effect of THC on human brain cancer cells, and that CBD offers hope of a non-toxic therapy that could treat aggressive forms of cancer without the painful side-effects of chemotherapy. - Martin A. Lee, Smoke Signals