Cancer

Abstract

In human history, cancer has been one of the most dreadful diseases because many cancer patients have died despite the intensive and extensive efforts. There are two factors known to play key roles in carcinogenesis. One is an environmental factor, and the other is a genetic factor. Various kinds of modalities, such as surgical treatment, radiation therapy, and chemotherapy, for cancer treatment have been developed and used for a long time. The trend for the development of antitumor chemotherapeutics is target therapy, in which the molecules involved in the oncogenic process are specifically blocked by inhibitory small molecules or blocking monoclonal antibodies raised against those molecules. The concept of a cancer vaccine has become the basis for a new trial to deal with the hurdles in the development of new immunotherapy technologies. Vitamin C levels in the peripheral blood of liver cancer patients were lower than those of healthy normal people. Vitamin C treatment has increased the numbers of lymphocytes and NK cells and production of IFN-$γ$ and granzyme B in cancer patients. A vitamin C concentration of at least 5--10 mM could kill the cancer cells directly through apoptosis or autophagy. Surprisingly, their killing was not carried out by the antioxidant activity of vitamin C but by its prooxidant activity. Besides the improvement in the sense of well-being of patients, there are many reasons why megadose vitamin C treatment should be recommended to cancer patients because it would have several beneficial effects. Conclusively, oral administration of a relatively high dose of vitamin C could prevent cancer formation by inhibiting the immune escape mechanism of cancer cells. A high dose of vitamin C up to 100 g could kill cancer cells directly. The treatment outcome could even be better if this modality is combined with several conventional treatment modalities.