About 5% to 10% of breast cancers are thought to be hereditary, caused by abnormal genes passed from parent to child.
Genes are particles in cells, contained in chromosomes, and made of DNA (deoxyribonucleic acid). DNA contains the instructions for building proteins. And proteins control the structure and function of all the cells that make up your body.
Think of your genes as an instruction manual for cell growth and function. Abnormalities (also called mutations) in the DNA are like typographic errors. They may provide the wrong set of instructions, leading to faulty cell growth or function. In any one person, if there is an error in a gene, that same mistake will appear in all the cells that contain the same gene. This is like having an instruction manual in which all the copies have the same typographical error.
Many inherited cases of breast cancer are associated with two abnormal genes: BRCA1 (BReast CAncer gene one) and BRCA2 (BReast CAncer gene two). But changes in other genes also are linked to breast cancer.
A study has found that abnormalities in the RECQL gene are linked to a higher risk of breast cancer in Polish and French-Canadian women.
The study was published online on April 27, 2015 by the journal Nature Genetics. Read the abstract of “Germline RECQL mutations are associated with breast cancer susceptibility.”
The RECQL gene provides instructions for making RecQ helicases. RecQ helicases are enzymes that help cells fix DNA damage. Other studies have found that mutations in the RECQL gene are associated with a higher risk of several cancers, including larynx, brain, and pancreatic cancer.
In this study, researchers at the University of Toronto looked at about 20,000 different genes from 195 women diagnosed with breast cancer. The women had a strong family history of breast cancer, but none of the women had an abnormal BRCA1 or BRCA2 gene.
The women came from two ethnic groups -- a Polish group and a French-Canadian group. Each group was genetically very homogenous. This means that each group had very similar genetics.
The researchers also looked at the genetics of 25,000 more people from the two populations, some who had been diagnosed with breast cancer and some who had not.
Within the Polish group of women, women who had one type of RECQL abnormality were five times more likely to be diagnosed with breast cancer than women who didn’t have the abnormality.
In the French-Canadian group of women, another RECQL abnormality occurred 50 times more often in women with a strong family history of breast cancer compared to women who didn’t have a strong family history of breast cancer.
The researchers said that in the general population, RECQL abnormalities are quite rare. Still, for the women in this study who had an abnormal RECQL gene, the risk of breast cancer was much higher than average.
The researchers expect to start studying groups of women from other countries to see if RECQL gene abnormalities are linked to a higher risk of breast cancer in other ethnic groups.
If you have a strong family history of breast cancer, yet you and your family members have tested negative for an abnormal BRCA1 or BRCA2 gene, you may want to talk to your doctor about this study and ask if being screened for a RECQL abnormality makes sense for you.
A strong family history of breast cancer usually means that you have a higher than average risk of breast cancer. The Gail score is a standard breast cancer risk assessment tool that assesses breast cancer risk based on a series of personal health questions that women and their doctors answer together. The questions ask about risk factors such as age, child-bearing history, family history of breast cancer, and breast biopsy results. The Gail score estimates the risk of developing invasive breast cancer in the next 5 years. If you think you may be at high risk for breast cancer, you might want to talk to your doctor about your personal and family medical history. You also may want to ask your doctor to consider calculating your Gail score and then talk about what it means.
For more information on genetics and breast cancer risk, visit the Genetics page in the Breastcancer.org Lower Your Risk section.
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