One of the key components in Matcha is the amino acid L-theanine, which is found almost exclusively in shade-grown green teas like Matcha. When L-theanine is combined with the natural caffeine in tea, it metabolizes more slowly, releasing the caffeine over a longer period of time and providing a stable three to six hour long energy boost (versus coffee caffeine at an hour to an hour and a half).
Studies on green tea’s impact on cancer have been mixed. But green tea is known to aid healthy cells in all stages of growth. There are some clues that green tea may help destroy cancer cells, but that research is still in its early stages, so you shouldn’t count on green tea to prevent cancer. In fact, the National Cancer Institute's web site says it "does not recommend for or against the use of tea to reduce the risk of any type of cancer."