Ashkenazi Jews and cancer

ALSO KNOWN AS: German or Eastern European Jews

DEFINITION: Although the major cancer risk factors in all populations are socioeconomic status, diet, lifestyles, and environment (which Jews in general share with other ethnic and racial groups), Ashkenazi Jews, originally from central, northern, and Eastern Europe, have some specific gene mutations that increase their susceptibility to certain forms of cancer.

Description of the population: In the ninth or tenth century, Ashkenazi (meaning "German" in Hebrew) Jews began settling in northern France and western Germany. At the beginning of the sixteenth century, their community became centered in Poland-Lithuania. For centuries, the religious and political isolation of the Ashkenazim (plural of Ashkenazi) within the larger host communities ensured their genetic purity, all the more so as they tended to intermarry. This means that the term "Jewish," in addition to religious and cultural denotations, can also refer to a common biological background distinct from that of others.

There are about ten million Jews in the world, the majority of whom are Ashkenazi rather than Sephardic Jews. Sephardic Jews, also known as Spanish or Oriental Jews, hail from Spain, Portugal, and North Africa and are in a minority in the United States as in most parts of the world.

Although American Jews, mostly Ashkenazim, are generally health conscious and respect medical science and its providers, so they tend to practice preventive health care, they are nevertheless more affected by specific disorders than members of other ethnic groups. Cancer researchers, starting in the 1990s, began to discover that particular gene mutations leading to cancers of the breast, ovaries, colon, and rectum were more prevalent among Ashkenazi Jews than in the population at large. This suggested a genetic origin.

Cancers of genetic origin: Ashkenazi Jews can trace their roots back to a small number of founders, several hundreds or thousands of them who originally lived in a confined environment and tended to intermarry. Geneticists theorize that if even a few of these founders had a gene mutation, this mutation would have been amplified in later generations of Ashkenazim, primarily because of intermarriage. This theory is confirmed by the fact that people of Ashkenazi Jewish descent have a higher incidence of several specific mutations, including those that increase the risk of developing certain types of cancer. Gene mutations cause such childhood neurological dysfunctions as Tay-Sachs disease and Bloom syndrome and are more prevalent among Ashkenazi Jews.

Breast and ovarian cancer: Isolated in 1994, BRCA1 is a major gene that, when one of its two copies is inherited in an altered form, predisposes individuals to breast (and ovarian) cancer. A different breast cancer gene, BRCA2 (for breast cancer 2), was also discovered to have greater prevalence among the Ashkenazim, bringing the overall risk factor among them even higher. In 2024, the Susan B. Komen Foundation published that 1 in 40 Ashkenazi inherits BRCA1 /2. Also, three distinct mutations in the BRCA1 and BRCA2 genes were found in 1 out of 40 Ashkenazi Jewish women, increasing their odds of getting breast or ovarian cancer. When these mutated genes are inherited from both parents rather than one, the disease risk is increased even further. According to 2020 figures from the National Cancer Institute, about 13% of all women will develop breast cancer in their lives.  

A study by the Journal of the American Medical Association (JAMA) published in June 2007 pointed out that in the case of breast cancer, the gene mutation may have originated from a woman's father rather than from her female antecedents. Half of genetic mutations for breast cancer are inherited from a father, not a mother. However, unless the father has female relatives with breast cancer, the faulty gene may have passed down unnoticed and without causing cancer (because breast cancer among men is rare). Accordingly, when a woman has few aunts or older sisters, a gene mutation can hide in a family tree so that it appears that her breast or ovarian cancer struck out of nowhere when it really originated from a mutation handed down by her father. In 2019, the British Journal of Cancer added that a family history of certain diseases, such as pancreatic, breast, and colorectal cancer, was linked with increased risk.

A woman with breast cancer who has a BRCA1 or BRCA2 gene mutation has a four times greater chance of developing cancer in the other breast and a ten times greater risk of developing ovarian cancer than a woman with breast cancer who has no BRCA gene alteration. This finding argues that women at greater risk, such as the Ashkenazim, should have genetic testing because three commonly used predictive methods do not accurately estimate the genetic breast cancer risk without a family history of such carcinomas. However, Orthodox Jewish rabbis may oppose genetic testing because it might cause couples to refrain from marriage and procreation. It must be borne in mind, too, that the Ashkenazim, like others, are subject to breast cancer risks independent of genetic causes.

Colorectal cancer: Ashkenazi Jews have a lifetime risk of colorectal cancer of 9 to 15 percent, one of the highest in the world, according to the Johns Hopkins Oncology Center. Although rare in the general population, the A636P mutation is detected in up to 7 percent of Ashkenazi Jews with early-onset colorectal cancer. Hereditary nonpolyposis colorectal cancer (HNPCC) is a dominantly inherited syndrome attributable to mutations in one of several deoxyribonucleic acid (DNA) mismatch repair genes, most commonly MLH1 and MSH2. Although rare in the general population, among Ashkenazi Jews, the MSH2 mutation is found to a greater degree with early-onset colorectal cancer. It may account for up to one-third of HNPCC.

Pancreatic and other cancers: Pancreatic cancer is the most fatal of all gastrointestinal cancers. Its survival rate is only 1 to 3 percent in the West, and the disease disproportionately affects the Ashkenazim. Men who inherit the altered BRCA1 gene are slightly more at risk of experiencing prostate cancer as well. Similarly, carcinomas of the stomach and non-Hodgkin lymphoma have a higher incidence among the Ashkenazim.

Interpreting statistics: Although Ashkenazi Jews have one of the highest lifetime colorectal cancer risks of any ethnic group in the world, carcinoma of the uterine cervix occurs very infrequently among them, and lung cancer among the Ashkenazim is also low, probably because of decreased tobacco use. The interpretation of statistics that portray variations in the incidence of cancer in any ethnic or religious group, including Ashkenazi Jews, must be carefully considered.

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