THC as a treatment for breast cancer?

UPDATES

It's by now fairly well known that marijuana has been used as an adjunct to chemotherapy. Patients who don't respond well to manufactured pain killers have found marijuana a particularly helpful remedy.

What is less well known is the possibility that a component of marijuana, THC ((delta)-9-Tetrahydrocannabinolmay) be an effective anti-cancer agent in its own right. In other words, some studies have found that THC actually kills tumor cells.

What is shocking to me are two facts. First, those rat studies that have been done on THC, mainly in Spain, are promising. Second, just how little research has been carried out on THC. I mean we are talking about a substance that's abundant, easy to produce, and shows some promise in the fight against cancer. Most of the serious research on THC and breast cancer is very recent.

Wast there a cover-up?
http://www.alternet.org/story/9257/

Note date of publication!
http://www.jci.org/articles/view/37948

Also very recent:
http://www.ncbi.nlm.nih.gov/pubmed/19428940?ordinalpos=1&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_RVDocSum

http://www.ncbi.nlm.nih.gov/pubmed/18454173?ordinalpos=2&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_RVDocSum

A study on human patients:
http://www.asco.org/ASCOv2/Meetings/Abstracts?&vmview=abst_detail_view&confID=47&abstractID=33960

Now, there has been some speculation in medical literature that marijuana could cause cancer.

However, having done some a quick survey, I can't find any studies that amount to anything more than speculation. Most of these discussions seem to relate to the notion that inhaling marijuana smoke might have negative effects on lung cells. We're not talking about actual studies, just theoretical speculation with regard to lung cancer. For example, Tashkin (2005):

The THC in marijuana could contribute to some of these injurious changes through its ability to augment oxidative stress, cause mitochondrial dysfunction, and inhibit apoptosis. On the other hand, physiologic, clinical or epidemiologic evidence that marijuana smoking may lead to chronic obstructive pulmonary disease or respiratory cancer is limited and inconsistent.

The main concern I have with THC is the appalling lack of research, but the good thing is that it has a long history of use -- something that can be said for few modern drugs. Relative to many pharmaceutical substances, the components of marijuana don't appear to pose especially high risk. Although a study done a couple of years ago seemed to link marijuana to schizophrenia in susceptible young people, the finding does not appear to hold up to scrutiny.

If you want to know how to make your own THC oil, some Canadians have produced a how-to guide:

http://www.phoenixtears.ca/diy.html

Update
I came across a US study of mice that appears to indicate that THC contributes to cancer growth in the breast under certain conditions. The authors try to explain the paradox, because it seems to contradict other research.

. . . findings suggest that marijuana exposure either recreationally or medicinally may increase the susceptibility to and/or incidence of breast cancer as well as other cancers that do not express cannabinoid receptors and are resistant to (delta)-⁹-THC-induced apoptosis. . . . .

Although direct epidemiological data linking marijuana exposure to increased incidence of breast cancers is not currently available, it is intriguing to speculate that immunocompromised individuals may become increasingly susceptible to MMTV-like infection and to the subsequent development of breast cancers. Therefore, the possibility exists that exposure to marijuana, either through recreational or medicinal use, may lead to increased incidence of immunogenic tumors.

http://www.jimmunol.org/cgi/content/full/174/6/3281

Update 2
I came across another article , that reviews the findings of the previously cited contradictory study (update 1) and other research on the topic. The athors conclude:

Cannabinoids are proving to be unique based on their targeted action on cancer cells and their ability to spare normal cells. Variation in the effects of cannabinoids in different cell lines and tumor model could be due to the differential expression of CB₁ and CB₂ receptors. Thus, overexpression of cannabinoid receptors may be effective in killing tumors, whereas low or no expression of these receptors could lead to cell proliferation and metastasis because of the suppression of the antitumor immune response. It is also reported that low doses of cannabinoid administration accelerate proliferation of cancer cells instead of inducing apoptosis and, thereby, contribute to cancer progression. Till date, very little is known about the mechanism of action of cannabinoids. There is need for further in-depth studies to elucidate the precise mechanism of cannabinoid action in cancer cells. Safety of (9)-tetrahydrocannabinol administration has been determined, and a dose escalation regimen showed that cannabinoid delivery was safe and could be achieved without overt psychoactive effects. In view of the fair safety profile of most cannabinoids together with their antiproliferative action on tumor cells, clinical trials are required to determine whether cannabinoids could be used for the inhibition of tumor growth in a clinical setting.

http://cancerres.aacrjournals.org/cgi/content/full/68/2/339

So what are they waiting for? Get those clinical trials underway!

Update 3
Here are some webpages linking to various studies about the potential of marijuana/thc in the treatment of various diseases listed here and more here.