The way I read the article was that cancer is caused by deficiencies in the body's repair mechanism. It appears as if some have a more robust mechanism than others, depending on genetics.

My mom had 14 siblings and only one of them got breast cancer (she was a nun and never breastfed which drastically increases a woman’s odds of breast cancer). But prior to that, her mother’s family, which was also large never had a case of cancer. My mom’s siblings also had around 30 kids between them some now in their 60s. There hasn’t been a single case of cancer amongst the kids either. So it’s something like 150 people with only one instance of cancer over the last 3 generations. There is definitely a strong genetic component to this.