@Icon,
250 is the MENSA registered cap as of the mid 80's.
It might also interest everyone to know that the average IQ was dropped from 130 to 100-110 which is a tad bit frightening.
As far as curing cancer, I hate biology and quarks can't be modified with mere thought since thought cannot create that much energy. Brain waves are only so powerful.
I challenege anyone to push their minds to the limit and see what can be done. As a being, we have not even touched on our abilities. The trick is to clear the mind, not fill it.
IQ is truly nothing more than how you manage to intake and relate data. For instance, when I look at things, I don't see a single picture. I pull in each object in view, calculate approximate distance, angle in relation to my POV, weight, mass in 0g, friction related to my mass, speed in which it travels, potential energy in newtons and then combine it all into a single image. Basically my IQ has done nothing more than allow me to become a GREAT estimator and read at about 760 per minute with a 98% retention rate. I still play chess like a child and have a hard time telling up from down after a good night of drinking.