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Ashkenazi Jews and Cancer Risk

Jewish Ancestry and Breast/Ovarian Cancer
Variations in the genetic sequence of particular genes can result in increased cancer risk. These variations are inherited from our parents and passed on to our children. The frequency and type of such changes (mutations) differs in different populations and ethnic groups. For example, researchers have found that there are three specific mutations in genes associated with breast and ovarian cancer that are especially common in Jewish women, especially Ashkenazi Jewish women. Two are alterations in the BRCA1 gene, and one is an alteration in the BRCA2 gene. The alterations in the BRCA1 gene and BRCA2 gene are present in approximately 1 in 40 individuals of Eastern European Jewish descent. Three well characterized mutations account for about 30% of cases of breast cancer in Jewish women younger than age 42, and for about 40% of ovarian cancer in Jewish women at any age. Genetic tests for these three mutations can be obtained from clinical laboratories at a cost of $300-$500. Individuals however should receive genetic counseling before undergoing genetic testing.

Genetic counseling and cancer risk assessment is appropriate for any person concerned about their personal or family history of cancer and how it relates to their risk for developing cancer in the future. For an accurate assessment, it is helpful to obtain information about the cancers that have occurred in the family (on both the maternal and paternal sides) including age of cancer onset, age of death and cause of death in all affected family members. Pathology records or death certificates confirming all cancers are very helpful. Based upon the information that is available, a cancer risk assessment can then help determine whether genetic testing is appropriate for a specific individual or family. During genetic counseling, the risks, benefits, and limitations of genetic testing for BRCA mutations are extensively discussed so that an informed decision can be made about moving forward with testing.

Patients electing to undergo genetic testing may benefit from the information provided since they will have a more accurate assessment of their risk to develop breast and ovarian cancer. They may avail themselves of options such as taking Tamoxifen, a chemoprevention agent that has been shown to reduce risk for breast cancer, or they may choose to undergo more intensive surveillance with clinical breast exams, mammograms, and breast MRI. In addition, some patients may be eligible to participate in research studies that may improve upon the early detection of cancer. Of course if an individual tests negative for a known mutation in the family, their risk will likely be the same as that of the average person, and they can follow general cancer screening guidelines for average risk individuals. It is important for patients who are concerned about their risk for cancer or who are considering the option of genetic testing, to be seen in a comprehensive cancer risk clinic that offers expertise in managing cancer risk and has clinical research trials available to eligible patients. In a comprehensive cancer risk clinic, patients can be advised by specialists, offered appropriate cancer risk management and follow-up, and be informed about clinical research trials that are likely to advance the field for future generations. A list of research trials at the University of Chicago can be found at www.uchicago.edu, www.cancer-risk.bsd.uchicago.edu, and the National Cancer Institute website (www.cancer.gov/clinical trials).

Jewish Ancestry and Colon Cancer
Colorectal cancer is a common cancer in the United States, affecting approximately 156,000 individuals yearly. Colon cancer has an average age of onset of 65 years and generally, there is no family history of this condition... However, there are several inherited forms of colon cancer that are characterized by the location of the cancer, the presence or absence of polyps, the age of onset and the occurrence of other cancers in multiple family members. Because colon cancer is a fairly common occurrence in the United States, it can be difficult to determine whether two cases of colon cancer have occurred in one family by chance or whether they represent an inherited type of colon cancer.

There are two known inherited colorectal cancer syndromes that occur in both Jewish and non-Jewish families. These syndromes are Hereditary Non-Polyposis Colorectal Cancer (HNPCC) and Familial Adenomatous Polyposis (FAP). Individuals who have HNPCC usually develop colon cancer by age 50 and often have other affected family members. Individuals who have FAP develop numerous polyps at a young age and frequently have a history of colon cancer occurring in family members by age 40.

In addition to the two genetic syndromes described above, a specific inherited mutation called I1307K, located in the Adenomatous Polyposis Coli (APC) gene, was identified in 1997. This mutation is found in approximately 6% of individuals of Ashkenazi Jewish ancestry. Individuals who have the I1307K mutation are at increased risk of developing colorectal polyps and cancer. Having this mutation does not itself cause colon cancer but does make the APC gene more susceptible to additional genetic changes that can cause colon cancer. A person who has this mutation has a 10-20% risk of developing colorectal cancer in his or her lifetime, compared to the general population risk of 6%. Individuals who test positive for this mutation should begin having routine colonoscopy at age 35, or 5 to 10 years before the earliest age of occurrence of colon cancer or colon polyps in the family. Individuals who have this mutation will have a 50% chance to pass it to each of their children.

Individuals of Ashkenazi Jewish ancestry with a personal history of colon cancer or colon polyps and a family history of at least one first-degree relative (mother, father, child, sister, brother) who had colon cancer or colon polyps may be appropriate for genetic testing. Individuals without a significant family history may still benefit from genetic counseling and cancer risk assessment to learn whether genetic testing may benefit them and to obtain cancer screening recommendations based upon personal and family history information.

Testing for the I1307K mutation is available clinically and there is ongoing research at various medical centers to better understand the risk associated with the I1307K mutation and the psychosocial aspects of having a mutation that most of the time will not lead to colon cancer. Eligible patients for these research studies are often provided with genetic counseling and genetic testing free of charge.

It is important for patients who are concerned about their risk for cancer or who are considering the option of genetic testing, to be seen in a comprehensive cancer risk clinic that offers expertise in managing cancer risk and has clinical research trials available to eligible patients. In a comprehensive cancer risk clinic, patients can be advised by specialists, offered appropriate cancer risk management and follow-up, and be made aware of clinical research trials that are likely to advance the field for future generations. A list of research trials at the University of Chicago can be found at www.uchicago.edu, www.cancer-risk.bsd.uchicago.edu, and the National Cancer Institute website (www.cancer.gov/clinical trials).

For more information about genetic counseling, cancer risk assessment, genetic testing, and research studies please contact the Chicago Center for Jewish Genetic Disorders

This article is courtesy of:

Melody White, MS, CGC
Genetic Counselor, Cancer Risk Clinic
The University of Chicago Medical Center

Marion Verp, MD
Associate Director, Cancer Risk Clinic
The University of Chicago Medical Center

Funmi Olopade, MD
Director, Cancer Risk Clinic
The University of Chicago Medical Center

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