What are Familial Cancers?
Some cancers run in families. About 10% of cancers are hereditary in nature. Examples are cancer of the breast, ovaries, colon, prostate, etc.. Here Many people have relatives who have had cancer, but most of the time this is due to chance or environmental factors. In a familial cancer syndrome, an inherited genetic mutation causes a person to be at increased risk for cancer and other physical symptoms. There are many different familial cancer syndromes, and each one has a specific set of characteristic cancers and physical symptoms associated with it. For example, BRCA1 and BRCA2 gene mutations are associated with an increased risk for breast and ovarian cancer. Examples of other familial cancer syndromes include von Hippel-Lindau syndrome,Peutz-Jeghers syndrome, and Li-Fraumeni syndrome.
Following are the features of hereditary cancers:
- Two or more close relatives with the same type of cancer (on the same side of the family).
- Cancer diagnosed at an earlier age than usual.
- Cancer diagnosed more than once in the same person (more than one primary cancer, not a cancer recurrence).
- Cluster of cancers associated with a known familial cancer syndrome (such as breast and ovarian).
- Many cases of cancer in a family, more than can be accounted for by chance.
- Cancer in a person who also has birth defects.
- Evidence of autosomal dominant inheritance, which is when a gene from one parent overrides that of the other parent. When one parent has a dominant abnormal gene, offspring each have a 50% chance of inheriting that gene.
