WASHINGTON (Reuters), Jun 20 - Researchers have found another breast cancer gene that can greatly raise the risk of the disease in women of European heritage, according to a report published on Monday.
They said the gene worked in tandem with the well-known BRCA1 and BRCA2 genes to raise the risk of breast cancer by as much as 80%.
The team, at Iceland's Decode Genetics, said their findings suggest women with certain mutations in two of the genes have an almost certain risk of breast cancer.
The new gene is called BARD1, Decode's team reports in the online journal Public Library of Science Medicine.
"The BARD1 variant works together with the BRCA2 mutation in Iceland and increases the likelihood of breast cancer from 45% in those who have only the BRCA2 mutation up toward 100% in those who also have the BARD1 variant," Decode chief executive Kari Stefansson said in a statement.
And women with the BARD1 variant who develop breast cancer are more likely to have tumors in both breasts, Stefansson said.
Breast cancer is known to run in families and has a genetic component, although most cases occur in people with no family history of the disease. Several genes are known to be involved, including the BRCA1 and BRCA2 genes, p53, and others.
The known BRCA1 and BRCA2 mutations only account for about 3% of all cases of the disease.
The Decode team is trying to find other genes that work with these genes.
They found 1,090 women in Iceland who had breast cancer, and compared them to 703 Icelandic women who did not. The company has a database carrying the genetic profiles of virtually everyone in Iceland.
A certain BARD1 mutation was found in 5.4% of breast cancer patients and 3.1% of women who did not have breast cancer -- an 80% increase in risk, the researchers said.
Simply having the BARD1 mutation was not especially dangerous to a woman, but women who had it and a specific mutation on BRCA2 had a "dramatic" risk of breast cancer, the researchers found.
It may be worth developing a test for that particular combination, the researchers and the company said.
This BARD1 mutation has been found in Italian and Finnish families with a history of breast and ovarian cancer.
It has not been found in people of Chinese, Japanese, African-American, and Yoruban descent, the researchers added.
"Therefore, the variant may be restricted to individuals with European ancestry and could contribute to the higher load of breast cancer seen in this group. However, other BARD1 variants have been discovered in African-American and Japanese individuals. The contribution of these variants to the risk of disease is still uncertain," they wrote.
Breast cancer is the second leading cause of cancer deaths among women after lung cancer, affecting 1.2 million women globally and killing more than 400,000 every year, according to the International Agency for Research on Cancer.
By Maggie Fox
Last Updated: 2006-06-20 9:11:19 -0400 (Reuters Health)
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![Examples of ultrasound findings and techniques. (A) Images in a 39-year-old male patient with a mass in the left thigh. The mass is heterogeneous on the B-mode US image (compared with the patient in D) and showed increased microvascularity (superb microvascular imaging [SMI]) and shear-wave elastography (SWE) values. Undifferentiated pleomorphic sarcoma was diagnosed at biopsy (with pleomorphic rhabdomyosarcoma in surgical specimen). (B) Images in an 18-year-old male patient with a mass in the left leg. The mass is hypoechoic on the B-mode image, with no other findings suggestive of malignancy. The lesion is in contact with the cortex of the tibia, which is slightly irregular. CT revealed a doubtful anteromedial tibial erosion. The microvascular study demonstrated high vascularization, suggestive of malignancy. Periosteal Ewing sarcoma was diagnosed with both histologic and immunohistochemical confirmation. (C) Images in a 69-year-old female patient with a lump growing on the outside of the left leg. Multiple SWE examinations were performed (please note the high values obtained in the measurements, whereas the color map highlights the stiffness relative to adjacent tissues). SMI showed areas of increased vascularization to target for sampling. Undifferentiated spindle cell sarcoma was diagnosed at biopsy, with residual leiomyosarcoma in the surgical specimen after neoadjuvant therapy. (D) Images in a 56-year-old female patient with a mass in the right thigh. The mass is heterogeneous at both B-mode ultrasound (similar to patient A) and MRI (coronal T2-weighted spectral attenuated inversion recovery [SPAIR]; T1-weighted pre-contrast and postcontrast imaging), which even shows uptake after the administration of paramagnetic contrast material, which is traditionally suggestive of malignancy. Low values at SMI and elastography are suggestive of benignity. Spindle cell lipoma was diagnosed at biopsy, with atypical spindle cell lipomatous tumor in the surgical specimen.](https://img.auntminnieeurope.com/mindful/smg/workspaces/default/uploads/2026/08/images-radiol250278fig2.APCFLSvX6p.jpg?auto=format%2Ccompress&dpr=2&fit=crop&h=167&q=70&w=250)
