Is cancer hereditary?

Around 5–10% of cancers are driven by inherited mutations such as BRCA1/2 or Lynch syndrome. A strong family history — several affected relatives, young ages at diagnosis, or the same cancer across generations — is a reason for genetic counselling.

Two first- or second-degree relatives with breast cancer is a reasonable trigger for genetic counselling, especially if either was diagnosed before 50.

Counselling before testing matters — results affect screening schedules, preventive options and other family members, so the implications should be understood first.