Whoever posted this is ignorant. Bill Gates has been donating money for medical research and specifically towards cancer research for a long long time.
When I was at UW in the early 90s, Gates donated a bunch of money to build a biotechnology center there and recruited the top scientist in biotech up to the Seattle area to try to establish Seattle as the world's foremost center of biotech research. I don't remember the specific details but it was a big deal in the news back then (I also remember the Seattle Times lamenting that Gates would spend his money on biotech labs but wouldn't buy the Seattle Mariners to keep them out of the hands of Japanese owners...one of the more lame things I've ever read in a newspaper).
One person cannot fund cancer research. It will take trillions and a lot of time to cure cancer. Bill Gates has already done more than all of us combined. We should just hope that he doesn't get cancer and keeps investing his money in good causes. Once Gates is out of the picture the guy who takes his place is more likely to buy private jets and mansions for himself. Why not ask Larry Ellison to sell off some of his yachts and pitch in?