The results of 2 international studies were published recently providing new insights into the inherited / family risk of breast cancer. DNA samples from hundreds of thousands of people worldwide, including some of those collected through our DietCompLyf Study, were analysed to compare the genes of women with and without breast cancer. This work may lead to improved screening, earlier detection and better treatments against breast cancer.
One of the studies, led by Professor Douglas Easton and colleagues, was published in the journal Nature and discovered 65 new genetic regions linked to risk. The second study, led by Dr. Roger Milne and colleagues and published in Nature Genetics, compared the genes of women with a specific type of breast cancer called oestrogen receptor negative (ER-) with those of women with a gene mutation already known to increase risk of breast cancer called BRCA1, and to those of women without breast cancer as a control group. They identified 10 new gene variations linked to ER- breast cancer risk and noted a strong link between the breast cancer risk for BRCA1 mutation carriers and the risk of ER- breast cancer in the general population.
Rebecca became aware that there was a genetic mutation passed down in her family when her paternal grandmother was enrolled into one of the earliest BRCA genetic studies in Australia back in 1995. She and her older sister saw a genetic counsellor who explained that they had a 50% chance of carrying the BRCA mutation that was present in their grandmother and father, and that this mutation increased one’s chance of getting breast cancer up to 80% over a lifetime. Rebecca explained “I knew that if my result was positive then I would be pro-active,
I would do whatever it took to reduce my risk as much as possible and that I wouldn’t want to wait around. This is the opportunity that my grandmother and her mother and sisters didn’t have.
Doctors can currently test family members for BRCA1, BRCA2 or other known gene mutations if increased inherited risk of breast cancer is suspected, which gives affected individuals the opportunity to reduce their risk by making changes to their diet and lifestyle and perhaps choosing preventative surgery. However, when these tests return a negative result it doesn’t rule out that inherited factors are at work because we haven’t yet defined all of these types of genetic mutations. This large scale research defines many new inheritable mutations which will help identify more individuals who are at a higher risk of developing breast cancer, and may shed more light on the differences between breast cancer types, facilitating diagnosis and treatment.
Some people are more susceptible to certain types of cancer because they have inherited a mutated version of a gene from one of their parents, which is why generations of some families experience many cancer diagnoses. Like a recipe, a gene encodes for proteins which a cell needs to function correctly, including to control cell growth. When a cell loses control of its growth, it can become cancerous. For example, when new DNA is made during normal cell growth, BRCA1 or BRCA2 proteins check the DNA to correct any mistakes made before a cell is allowed to divide into 2 cells. People with mutated versions of the BRCA1 or 2 genes are known to have an increased risk of breast, ovarian, pancreatic and prostate cancer because mutated BRCA1 or 2 proteins do not function correctly, or may not be produced at all. Without a fully functioning error-correcting system, cells are more likely to become cancerous because damaged DNA will accumulate as the cells divide over time, which can eventually allow cell growth in an uncontrolled manner, leading to cancer. For further reading, the full research papers are available in the journals Nature and Nature Genetics.
By making available to other research groups the data and biological samples collected during our Diet & Lifestyle study, supporters of Against Breast Cancer can be reassured that we are committed to sharing our own research and resources with other groups and academic establishments. It is a privilege to contribute to such important work and we anticipate supporting other similar research projects in future. Read more about our Research Strategy here.