Chance? Behavior? I've had 3 close relatives die from cancer (Grandpa, Grandpa, Grandma - Lung, Lung, Brain). Adding 3 more people to a list like that isn't far fetched. In developed countries - Cancer is a huge killer, worldwide - it kills 13% of people.
Also note that the poster said close family members fought cancer a double-hand number of times. That could mean over 5 people, though it could also mean one or more family members had multiple run-ins with cancer, surviving at least the first few times.
