I don't know. Who? It's really hard to tell. I think pharmaceutical companies produce a lot of them, but I wouldn't consider them a "health care system" as the

I don't know. Who? It's really hard to tell. I think pharmaceutical companies produce a lot of them, but I wouldn't consider them a "health care system" as they are typically public companies, nor would I consider their IP to be a "contribution". The large pharma companies are often in the US and Switzerland, but much of their revenues are not cancer related so it is hard to work out which one is doing the most.