There can be mutated DNA that pre-disposes people to get certain cancers. I'm going in for my hereditary test in a couple weeks to start to see if I have that. It's not the PC causes other cancers or other cancers cause PC, but bad DNA can just be allowing cancers to appear in the first place, at least according to modern science.

The only reason I really want the test is to know if I have mutated DNA and if I should warn my brother to get checked, otherwise it is what it is and there's nothing I can do about it. I also see this as an "egg scenario" where today eggs are good, but they've been bad, then good, then bad, then good - the point being that science is always changing their viewpoints on these things so absolutely anything is possible.