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Connection Between A-T and Breast Cancer

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April 2001

"1% to 2% of the population may be at increased breast cancer risk because they carry a single copy of an ataxia telangiectasia gene mutation.[4] Since cancer susceptibility is increased by having only 1 copy of the gene, susceptibility is inherited as an autosomal dominant trait."
Reader’s Digest Health, provided by the National Cancer Institute (NCI)
Genetic Testing for Cancer Risk
April 11, 2025
(full text available at http://rdhealth.com/kbase/nci/306287.htm )

"Further, the ages of onset of breast cancers are important, with younger ages of onset being more likely associated with a deleterious mutation, especially a mutation in BRCA1.[32] Women who carry an abnormal AT (ataxia telangiectasia) gene may be at increased risk of breast cancer,[33] but it is not clear that these women are at increased risk of early-onset breast cancer (diagnosed at age 40 or younger."
Reader’s Digest Health, provided by the National Cancer Institute (NCI)
Prevention of Breast Cancer
April 11, 2025
(full text available at http://rdhealth.com/kbase/nci/304730.htm )

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November 2000

"This (Sloan-Kettering Institute for Cancer Research) work involves Ataxia-Telangiectasia (AT), which is an autosomal recessive disorder characterized by neurologic and other abnormalities as well as an approximately 100-fold increase in cancer incidence. A single gene, ATM, appears to be mutated in the majority of AT families. ATM functions as a central component of the cellular response to DNA damage. It has been postulated that heterozygotes for ATM mutations have an increased susceptibility to radiation-induced breast cancer. To test this hypothesis, a study is performed to test the frequency of ATM mutations in woman with breast cancer after therapeutic radiation therapy for Hodgkin's disease. Cases are compared to matched controls treated for Hodgkin's disease with no breast cancer. No truncating mutations of ATM are observed in either group, and no difference is found in the rate of missense mutations (37% controls vs 21% cases). Some missense mutations are observed at polymorphic (>1%) frequencies. Further studies analyzing the frequencies of these mutations in the general population, as well as functional studies, will be necessary to resolve their potential role as susceptibility alleles for lymphoid cancers. (Order the full report from InfoTeam Inc., P.O. Box 15640, Plantation, FL 33318-5640; Phone (954) 473-9560, Fax (954) 473-0544)" from www.findarticles.com

Germline Mutations Of The Ataxia-Telangiectasia Gene (Atm) As A Risk Factor For Radiation-Associated Breast Cancer.
Life Sciences & Biotechnology Update, November 01 2000

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November 1999

"A new study published in the Journal Science in November of 1999 identifies a probable explanation of the A-T gene’s role in breast cancer. The A-T gene was found to be critical in phosphorylating the breast cancer gene, thereby protecting it from radiation damage. The importance of this discovery, which had long been suspected but never confirmed, is not only that the A-T breast cancer link is more clear, but also that a broader understanding of the A-T gene’s role in other cancers is occurring.

"As a result of this and other findings, worldwide A-T research is further intensifying. Because breast cancer is of such general interest, we can expect an exponential rate of A-T discoveries that will in turn lead to many more."

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August 1998

"Genetic predisposition accounts for 5-10% of breast cancer, and two genes BRCA1 and BRCA2 have attracted most attention as high risk factors. However, these two genes probably account for only a small proportion of the genetic risk while other more common but less penetrant genes may explain the remainder of genetically predisposed breast cancers. One such candidate is the gene, ATM, mutated in the human genetic disorder ataxia-telangiectasia (A-T). A-T heterozygotes (estimated to be 1% of the population) do not show any of the major symptoms of the disease, though there is good evidence that they have an underlying cellular radiosensitivity, but to a lesser extent than observed in A-T homozygotes. These observations, together with earlier epidemiological studies, reveal a raised incidence of mortality from cancer among blood relations of patients with ataxia-telangiectasia, with the greatest relative risk for breast cancer (5.1) in female relatives of patients. "

Role of the ataxia-telangiectasia gene (ATM) in breast cancer
Martin Lavin, Ph.D.
British Medical Journal 1998;317:486-487 ( 22 August 2025 )
(full text available at http://www.bmj.com/cgi/content/full/317/7157/486 )