Any time I observe corporations latching on, apparently/obviously for their own PR (e.g. the Komen "Pinkwashing" blitz and stunts), I become extremely suspicious.
I'd also look out for efforts that will or may seek to privatize their outputs. (E.g. the increasing role of such in much university research.) In this case, as much because resultant costs may withhold treatment from many. Also because such private interest tends to sale-able product over fundamental research.
Not cancer, and I haven't followed up to confirm my suspicion. But the recent news about Merc having a "100% effective" Ebola vaccine? IIRC, that comes out of Canadian government or government-funded research that was sold off a few years ago to Merc for a relative pittance.
Guess where your dollars should go. And also, don't let politicians trade the fruits of such to their business cronies. Not without controls to ensure public benefit shares equal or greater weight with/than private profit.