It has been reported that some people have taken Beta Glucan and been cured of their cancer. I believe (12 years experience with alternative cancer support via the largest such web site on the Internet) that such people had marginal body systems that were almost able to deal with their cancer and only needed a little help.
Beta Glucan does boost the immune system, but the immune system is designed to deal with such things as bacteria that are not made by your body. Cancer tumors are created by the body. Therefore, the immune system is not going to destroy cancer cells. Disregard those studies that claim that laboratory experiments have shown that immune system "killer T cells" kill cancer cells. These experiments are performed in test tubes not in the body and that is a tremendous difference.
With that said, strengthening the immune system has helped cancer patients. This apparent contradiction is understood when you consider that bacteria and parasites
damage the body where they reside and cause the body to go into repeated healing mode. Repeated healing can eventually lead to cancer if secretions from the pancreas fail to stop trophoblast cells (used in healing) from multiplying. If the immune system can be boosted sufficiently to remove most of the bacteria and parasites
in the body, the amount of healing happening in the body is greatly reduced. This removes the strain on the pancreas caused by all that healing activity. Now the limited output (due to modern diet) of the pancreas can concentrate on the tumor which is just a large collection of trophoblast cells.
So Beta Glucan can help, but it is not a frontline cancer fighter. If you would like more on Beta Glucan, you can visit my free Beta Glucan
web page. I do not sell supplements.