While cannabis smoke has been implicated in respiratory dysfunction, including the conversion of respiratory cells to what appears to be a pre-cancerous state , it has not been causally linked with tobacco related cancers  such as lung, colon or rectal cancers. Recently, Hashibe et al  carried out an epidemiological analysis of marijuana smoking and cancer. A connection between marijuana smoking and lung or colorectal cancer was not observed. These conclusions are reinforced by the recent work of Tashkin and coworkers  who were unable to demonstrate a cannabis smoke and lung cancer link, despite clearly demonstrating cannabis smoke-induced cellular damage.
Furthermore, compounds found in cannabis have been shown to kill numerous cancer types including: lung cancer , breast and prostate , leukemia and lymphoma , glioma , skin cancer , and pheochromocytoma .