If cancer research is a government charity why is it not funded enough by the government?

They're pretty well paid (the scientists) and they do a lot of expensive research..

If cancer research is a government charity why is it not funded enough by the government?
A cure for Cancer was found in the late 70's...but was soon Hushed up...The Government makes a Billion Pounds a year from Cancer Research...also if the cure was leaked then there would be over population all over the world.