Most cancers occur by chance, and can be the result of lifestyle choices such as smoking, or environmental conditions such as exposure to ultraviolet rays from sunlight or chemicals in the home or workplace. However, in some families, cancer occurs more often than can be blamed on chance.
If there is an inherited gene mutation in the family, cancer risks are much higher than in the general population. There are several clues that may show whether an inherited factor is causing cancer in a family:
- Multiple cases of an uncommon type of cancer such as pancreatic cancer
- Cancer that occurs at an earlier age than in the main population, such as breast or colon cancer in a 30-year-old
- More than one type of cancer occurring in one person, such as a woman experiencing both breast and ovarian cancers
- Cancer that occurs in both of a pair of organs—both eyes, kidneys, or breasts, for example
- Childhood cancer that appears in siblings, such as sarcoma in both a brother and sister
Research has identified many types of cancer that can be inherited. Take the heredity cancer quiz to understand your risk.