Frequently Asked Questions

 

What is deCODE BreastCancer ™?
The deCODE BreastCancer™ test is a novel, DNA-based reference laboratory test for the first common genetic risk factors to be indentified that contribute to a substantial proportion of female breast cancers arising in the general population. The test assesses relative genetic risk for the individual tested and the calculated lifetime risk based on the relative risk results and the background population lifetime risk (12.3% in the United States).
deCODE BreastCancer™ looks at 7 markers (SNPs) in the DNA isolated from an inner cheek or a blood sample.  The risks associated with each marker allele are multiplied together to define risks of 0.4- to 4.0-fold relative to the general population.   It is estimated that these 7 markers together account for 60% of breast cancer occurrences (population attributable risk).  According to the test results, only about 5% of women have an average 2-fold risk for breast cancer compared to the general population and about 1% have an average 3-fold risk. This translates for white women to a lifetime risk of 24% and 36%, respectively, versus the average lifetime risk of 12%. These common genetic variants do not explain risk due to family history of breast cancer, in fact, numerous studies have shown that the risk is independent of family history. Therefore, the test is useful for the 70 to 80% of the population that does not have a family history of breast cancer as well as those that have a positive family history for breast cancer.
Some of the genetic markers also seem to influence the penetration of BRCA1 and BRCA2 mutations when present, and, therefore, may have relevance in clinical decision making for individuals carrying BRCA mutations.
The test also predicts the likelihood of the cancer being estrogen receptor positive (ER+), if it occurs.  It is thought that tamoxifen only has effects on ER+ tumors.

Why take deCODE Breast Cancer™?
There are 3 reasons for using the deCODE BreastCancer™ test for defining a patient’s genetic risk for breast cancer.
1) According to the American Cancer Society (ACS), high-risk women with a 20% lifetime risk (or  a relative risk of 1.65 based on the deCODE BreastCancer™  test) should have a yearly breast MRI added to the usual yearly mammography beginning at age 40.   MRI can detect many more early tumors before they spread than standard mammography, but it is only recommended for higher-risk women. The ACS also recommends that physicians consider breast MRI for patients who have a modestly high risk for breast cancer based on lifetime risks of 15 to 20% (relative risks of 1.25 to 1.65).
2) According to the American Society of Clinical Oncology (ASCO), higher-risk women (defined as having greater than a 1.66% 5-year risk) should consider with their physicians whether to use tamoxifen (or similar drugs that also block the effects of estrogen, which can drive small tumors into larger tumors) as a preventive measure.  The average 55-year-old woman has a 1.2% risk of developing breast cancer over the next 5 years.  If her deCODE BreastCancer™ result showed a genetic risk of 1.4, her total 5-year risk of 1.7 would make her a candidate for preventive therapy, whereas based on conventional risk factors, she would be considered to have an average risk. 
3) Patients who have a strong family history of early-onset breast cancer in multiple first-degree relatives are often tested for mutations in the BRCA1 and BRCA2 genes.    Several of the genetic variants used in the deCODE BreastCancer™  test increase the lifetime risk for breast cancer in women positive for the BRCA1 or BRCA2 gene mutations. The test is also useful in parallel to BRCA1 and BRCA2 testing since it may reinforce that patients who are negative for BRCA1 and BRCA2 may still be at increased risk for later-onset breast cancer.

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What is this test based on?
The validity of the 7 variants tested as common risk factors for breast cancer has been confirmed in a number of large, multi-national studies including more than 10,000 patients and 30,000 controls. According to these studies, the risks associated with the markers are independent of each other and, to a large extent, also of other conventional risk factors used in risk assessment tools such as the Gail model. This has the implication that risks identified manually or by models that do not take into account the possible presence and effect of multiple genes of differing penetrance can be multiplied by the relative genetic risk results of deCODE BreastCancer™ test.

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What is a genetic risk factor for a common disease and why is understanding inherited risk important?
A genetic risk factor for a common disease is a specific version of a marker in the sequence of the genome that correlates with an increased likelihood of developing a given disease. Common diseases such as breast cancer occur at the interface of genes and the environment, as inherited as well as environmental and other health-risk factors play important roles in the disease process. As a result, it is important to understand what carrying an inherited risk variant for a common disease means, and how that information can be used to develop and implement disease prevention strategies that can effectively reduce the likelihood of an individual ever developing the disease, or effectively manage the consequences of the disease.
In basic terms, carrying a genetic risk variant for a common disease does not mean that one will necessarily develop the disease; and not having a certain risk variant does not eliminate the possibility of getting the disease. Rather, for the common diseases, genetic risk variants impact the likelihood that one may develop the disease. Understanding this inherited risk is empowering information with potentially important clinical utility. By understanding inherited risk, it is possible to take preventive action against breast cancer in concordance with recommended screening guidelines through lifestyle modification, or by taking certain medications (like tamoxifen in the case of breast cancer).

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Should test results be interpreted differently for different ethnic groups?
The results are at this time only applicable to white European females since research data are not currently available for other ethnicities for all the genetic variants.

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Why is understanding genetic risk important for breast cancer?
The deCODE BreastCancer™ test provides new information on the genetic risk contribution of 7 highly significant DNA variants, risk information that seems in general to be an addition to the currently used risk-assessment tools, but is not a replacement. It seems to be specifically important for the group of women who will be moved up or down in risk category by multiplication of their basic or modeled risk with the deCODE BreastCancer TM results.
The deCODE BreastCancer™ test makes a significant contribution to modifying basic or modeled risks since it is to a great extent independent of the individual factors currently used in attempts to estimate future breast cancer risk in individuals.   Validations of the significance and magnitude of association for each of the 7 SNPs evaluated in the deCODE BreastCancer™ test are based on studies of 4,500 to 26,000 breast cancer cases and between 17,500 and 32,000 controls. deCODE and others have shown that the markers used are independent of immediate family history, breast density, menarche, age of first pregnancy, and nulliparity. The deCODE BreastCancer™ test results represent an independent, validated set of risk factors that is an important addition to the currently recognized risk factors for breast cancer. 

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Is deCODE Breast Cancer™  an FDA approved test?
No, deCODE BreastCancer™ is a reference laboratory test that has not been cleared or approved by the FDA. The laboratory that conducts the test is registered as a high-complexity laboratory under the Clinical Laboratory Improvement Amendments (CLIA). The clinical utility of this test as a means of assessing inherited susceptibility to breast cancer, as presented on this site and elsewhere, is based upon published studies by deCODE and independent researchers demonstrating the correlation of carrying at-risk deCODE BreastCancer™ genotypes and the increased likelihood of breast cancer.

What scientific publications support the value of this test?

deCODE is widely recognized as the world leader in the discovery of genes contributing to the risk of common diseases. deCODE has also led the way in publishing its discoveries, a commitment that not only drives ongoing research but also enables independent researchers from around the globe to validate the company’s discoveries. deCODE has published its discoveries of breast cancer risk variants on chromosomes 2, 5, and 16, as well as discovering that many of the common variants are preferentially associated with ER+ breast cancer. These and other studies incorporated into the deCODE BreastCancer™ test have been published extensively in the international scientific press.

Stacey SN et al, Common variants on chromosomes 2q35 and 16q12 confer susceptibility to estrogen receptor-positive breast cancer.Nat Genet. 2007 Jul;39(7):865-9. Epub 2007 May 27.PMID: 17529974

Stacey SN, et al. Common variants on chromosome 5p12 confer susceptibility to estrogen receptor-positive breast cancer. Nat Genet. 2008 Jun;40:703-6.

Hunter DJet al.A genome-wide association study identifies alleles in FGFR2 associated with risk of sporadic postmenopausal breast cancer.Nat Genet. 2007 Jul;39(7):870-4. Epub 2007 May 27.PMID: 17529973

Fletcher O, Johnson N, et al.Cancer Epidemiol Biomarkers Prev. 2008 Mar;17(3):702-5. PMID: 18349290

Gold Bet al. Genome-wide association study provides evidence for a breast cancer risk locus at 6q22.33.Proc Natl Acad Sci U S A. 2008 Mar 18;105(11):4340-5. Epub 2008 Mar 7. PMID: 18326623

Raskin L, et al. FGFR2 is a breast cancer susceptibility gene in Jewish and Arab Israeli populations.Cancer Epidemiol Biomarkers Prev. 2008 May;17(5):1060-5. PMID: 18483326

Garcia-Closas Met al. Heterogeneity of breast cancer associations with five susceptibility loci by clinical and pathological characteristics.PLoS Genet. 2008 Apr 25;4(4):e1000054. PMID: 18437204

For a complete list of relevant and referenced publications, click here.

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How can I order the test?
You can have any licensed physician order your deCODE Breast Cancer ™ following the simple steps outlined in Ordering deCODE Breast Cancer™.

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Payment and Reimbursement
Payment can be made by any major credit card by the individual or by the ordering physician or clinic, by including the card details on the test request form. Samples submitted anonymously must be accompanied by a valid credit card number from the respective doctor or affiliated healthcare institution.

deCODE plans to make the deCODE BreastCancer™ test as widely available as possible and is working with physicians, patients, and their insurers on reimbursement. For more information, contact customer service at diagnostics@decode.com, or by phone at 1-877-222-6510.

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How can I get additional information?
If you would like additional information on deCODE BreastCancer ™, you can contact deCODE at diagnostics@decode.com, or by phone at 1-877-222-6510, and a deCODE representative will respond promptly to your questions.

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