Question

What does it mean to be predisposed to getting cancer? if you inherit a mutated cell cycle gene, does that automatically mean that you will get cancer some day? if you inherit a mutated cell cycle gene and participate in risky behaviors such as sunbathing, does that mean that you will automatically get cancer some day?

Answer 1

Predisposed mean increased the risk of developing cancer.  In most case, it doesn't mean that you will 100% develop cancer but your chance will be much higher than other people.
That risk also can be increased if you doing risky behavior like sunbathing. Again, that doesn't mean you automatically get cancer someday.