[sandworm101]

Isn't cancer predicated on mutations that result in uncontrolled cell growth? I imagine there are a great many mutations that result in cell death or an inability to properly divide. Those mutations wouldn't contribute to cancer risk. So maybe you need 3-6 but only amongst those bits of DNA that actually matter.

[nonbel]

Yes, that is correct. It would only be some "special" combinations of mutations, not just any set.