Additional Information

NBN gene

Associated Syndrome Name: NBN-associated Cancer Risk

NBN Summary Cancer Risk Table

Cancer Genetic Cancer Risk
Female BreastElevated Risk
ProstateElevated Risk

NBN gene Overview

NBN-associated Cancer Risk 1, 2, 3, 4, 5
  • Women with NBN mutations have a risk for breast cancer that is thought to be increased over the 12.5% lifetime risk for women in the general population of the United States.
  • Men with mutations in the NBN gene are thought to have an increased risk for prostate cancer.
  • NBN mutations are most common in patients of Slavic ancestry, where a single founder mutation (c.657_661del) is estimated to be present in 1:167 individuals. Current female breast cancer and male prostate cancer risk estimates are based primarily on studies of individuals of Eastern European ancestry with this specific mutation, and may not apply to other NBN mutations or patients of other ancestries.
  • It has been suggested that patients with NBN mutations have an increased risk for cancers other than breast and prostate cancer. In particular, there is evidence for an association with pediatric leukemias and lymphomas. The data for this are not conclusive at this time and there are no current medical management recommendations associated with pediatric cancer risk for carriers of NBN mutations.
  • Although there are increased risks for cancer in men and women with mutations in NBN, there are interventions that may reduce these risks. Guidelines from the National Comprehensive Cancer Network (NCCN) that may apply are listed below. Since information about the cancer risks associated with NBN mutations is relatively new, and there is still some uncertainty about the best ways to reduce these risks, it may be appropriate to interpret these results in consultation with cancer genetics experts in this emerging area of knowledge.

NBN gene Cancer Risk Table

Cancer Type Age Range Cancer Risk Risk for General Population
Female BreastTo age 801, 2, 6Up to 30%10.2%
ProstateTo age 803, 5, 6Increased risk10.9%

NBN Cancer Risk Management Table

The overview of medical management options provided is a summary of professional society guidelines as of the last Myriad update shown on this page. The specific reference provided (e.g., NCCN guidelines) should be consulted for more details and up-to-date information before developing a treatment plan for a particular patient.

This overview is provided for informational purposes only and does not constitute a recommendation. While the medical society guidelines summarized herein provide important and useful information, medical management decisions for any particular patient should be made in consultation between that patient and his or her healthcare provider and may differ from society guidelines based on a complete understanding of the patient’s personal medical history, surgeries and other treatments.

Cancer Type Procedure Age to Begin Frequency
(Unless otherwise indicated by findings)
Female BreastBreast awareness - Women should be familiar with their breasts and promptly report changes to their healthcare provider. Periodic, consistent breast self-examination (BSE) may facilitate breast awareness.9IndividualizedNA
Clinical encounter, including clinical breast exam, ongoing risk assessment and risk-reduction counseling9When genetic risk is identifiedEvery 6 to 12 months
Mammography with consideration of tomosynthesis and consideration of breast MRI with contrast8Age 40, or modified to a younger age based on the family history of breast cancerAnnually
Consider additional risk-reduction strategies.8, 9IndividualizedNA
ProstateCurrently there are no specific medical management guidelines for prostate cancer risk in mutation carriers. However, the possibility of an increased risk for prostate cancer can be incorporated into the risk and benefit discussion about offering screening with digital rectal examination (DRE) and Prostate Specific Antigen (PSA).745 years, or youngerIndividualized

Information for Family Members

The following information for Family Members will appear as part of the MMT for a patient found to have a mutation in the NBN gene.

A major potential benefit of myRisk genetic testing for hereditary cancer risk is the opportunity to prevent cancer in relatives of patients in whom clinically significant mutations are identified. Healthcare providers have an important role in making sure that patients with clinically significant mutations are informed about the risks to relatives, and ways in which genetic testing can guide lifesaving interventions.

In rare instances, an individual may inherit mutations in both copies of the NBN gene, leading to the condition Nijmegen Breakage Syndrome (NBS). Individuals with NBS will have growth retardation, immunodeficiency, and a greatly increased risk for varied types of cancer diagnosed at young ages. The children of this patient are at risk of inheriting NBS only if the other parent is also a carrier of an NBN mutation. Screening the spouse/partner of this patient for NBN mutations may be appropriate, particularly if they are of Eastern European ancestry, since NBN mutations are more common in this group.4


  1. Steffen J, et al. Germline mutations 657del5 of the NBS1 gene contribute significantly to the incidence of breast cancer in Central Poland. Int J Cancer. 2006 119:472-5. PMID: 16770759.
  2. Zhang B, et al. Genetic variants associated with breast-cancer risk: comprehensive research synopsis, meta-analysis, and epidemiological evidence. Lancet Oncol. 2011 12:477-88. PMID: 21514219.
  3. Cybulski C, et al. An inherited NBN mutation is associated with poor prognosis prostate cancer. Br J Cancer. 2013 108:461-8. PMID: 23149842.
  4. Varon R, et al. Nijmegen Breakage Syndrome. 2017 Feb 2. In: Pagon RA, et al., editors. GeneReviews® [Internet]. Available from http://www.ncbi.nlm.nih.gov/books/NBK1176/ PMID: 20301355.
  5. Cybulski C, et al. NBS1 is a prostate cancer susceptibility gene. Cancer Res. 2004 64:1215-9. PMID: 14973119.
  6. Fast Stats: An interactive tool for access to SEER cancer statistics. Surveillance Research Program, National Cancer Institute. https://seer.cancer.gov/faststats. (Accessed on 1-2-2017)
  7. Carroll PR et al. NCCN Clinical Practice Guidelines in Oncology®: Prostate Cancer Early Detection. V 1.2018. March 12. Available at http://www.nccn.org.
  8. Daly M et al. NCCN Clinical Practice Guidelines in Oncology®: Genetic/Familial High-Risk Assessment: Breast and Ovarian. V 2.2019. July 30. Available at http://www.nccn.org.
  9. Bevers TB, et al. NCCN Clinical Practice Guidelines in Oncology®: Breast Cancer Screening and Diagnosis. V 2.2018. May 18. Available at http://www.nccn.org.
Last Updated on 09-Jul-2019