Genetic link for Ovarian Cancer
Christina S. Chu, MD
Last Modified: January 6, 2002
Dear OncoLink "Ask The Experts,"
Please can you tell me if there is a known genetic link for ovarian cancer? My daughter- in-law is concerned because her mother died with the disease. She lives in the UK. Is there any way of calculating the risk? As far as I know there have not been other affected family members.
Thank you in anticipation.
Christina S. Chu, MD, Assistant Professor of the Division of Gynecologic Oncology at the University of Pennsylvania Health System, responds:
About 5-10% of ovarian cancer cases arise in families with multiple members affected by ovarian, breast, colon, or uterine cancer. In many of these families, cancer susceptibility appears to be an inherited genetic trait, passed down to succeeding generations in a dominant fashion.
Hereditary breast-ovarian cancer syndrome is usually seen in families with a history of cancer affecting first- and second-degree relatives. Women from these families tend to develop breast and/or ovarian cancer at a young age, and breast cancer may occur in both breasts. A woman who develops both breast and ovarian cancer has a very high likelihood of carrying a hereditary cancer syndrome. About 80-90% of these cancers are caused by mutations in the BRCA1 gene, with mutations in the BRCA2 gene being linked to most of the remaining cases. Patients carrying mutations in BRCA 1 have a risk of breast and ovarian cancer that may be as high as 80% and 60%, respectively. Recent evidence has shown that patients with ovarian cancer associated with genetic mutations in BRCA1 may have a better prognosis.
Lynch II syndrome, or HNPCC, occurs in families with a combination of hereditary colon cancer and cancers of the ovary, breast, endometrium, and other gastrointestinal sites. This syndrome is a less common cause of ovarian cancer, accounting for only about 2% of familial cases.
In your sister-in-law's case, there is no simple way to calculate her risk of developing ovarian cancer. If she is concerned, I would recommend she seek out a cancer risk evaluation program in her area, or speak to her gynecologist. In genetic screening programs, trained genetic counselors take very detailed family histories to determine a patient's particular risk for carrying a genetic problem. If the risk is determined to be sufficiently high, a patient may elect to undergo testing for genetic mutations in genes associated with hereditary ovarian cancer.
OncoLink has joined forces with the National Colorectal Research Alliance to help their scientists study the risk factors associated with colorectal cancer and identify potential preventive and treatment therapies. You and your family may be interested in taking our survey. This confidential survey was developed by cancer experts as an interactive way to help our leading scientists study families with a history of colorectal, breast, and ovarian cancers.