(HealthDay News) -- Family cancer syndrome is caused by an abnormal gene that is passed down from the preceding generation.
Only about 5 percent to 10 percent of all cancers are thought to be caused by genetic mutations, the American Cancer Society says.
It may be difficult to determine if a cancer is caused by an inherited mutation. The ACS mentions these factors that indicate the possibility of family cancer syndrome:
- Multiple cases in the same family of the same type of cancer (especially if the cancer is rare).
- Cancer that occurs in family members who are younger than usual (such as colon cancerin a 20-year-old).
- More than one type of cancer in the same person (such as a woman who has developed both breast and ovarian cancer).
- Cancer that develops in both sets of the same organ (such as both eyes, both kidneys or both breasts).
- More than one childhood cancer that develops in siblings (such as sarcoma in both a brother and a sister).
- Cancer that develops in a gender that is not typically affected (such as breast cancer in a man).
- Cancer that develops in multiple generations (such as a grandfather, father and son).