First of all im posting this here so you will all read this. (Sorry) Marijuana shrinks tumors and the government have known since 1974, and not told anyone. Here is the link: http://www.mapinc.org/newscc/v01/n572/a11.html
Well, i head about this in the news on WebMD a while ago. So here's a more credible link to where the information came from. http://www.webmd.com/lung-cancer/news/20070417/marijuana-may-fight-lung-tumors
I don't believe marijuana shrinks.. but actually inhibits the growth of tumors.. meaning it stops tumors from growing larger.. but not shrinking