Mutations in the BRCA1 and BRCA2 genes are linked to a dramatically increased risk of breast and ovarian cancers but did you known that pancreatic cancer is the third most common cancer associated with such mutations?
Although there is good awareness of the links between genetic mutations and breast or ovarian cancer, the genetic component of pancreatic cancer is less well known. World Pancreatic Cancer Day was recently on 21 November – we are looking at role played by BRCA1 and BRCA2 in pancreatic cancer and considering how genetic testing might help people at increased risk to manage their health more proactively, as well as influencing treatment if they become ill.
Why do BRCA mutations increase your risk of pancreatic cancer?
The genetics of pancreatic cancer are complex and it is not possible to predict with absolute certainty whether someone will develop the condition or not. The normal function of BRCA genes is to repair damage to DNA. BRCA1 and BRCA2 are tumour suppressor genes, acting to prevent normal, healthy cells from becoming cancerous. However, when the genes fail to function properly, DNA damage can build up, leading to unregulated cell growth. In some people, this can result in pancreatic cancer.
Does everyone with BRCA mutations go on to develop the disease?
No. Genes occur in pairs so you may have one healthy and one mutated BRCA gene. In this case, although your risk of cancer is heightened, it is not inevitable that you will develop the disease. You may go on to develop pancreatic cancer if you are exposed to certain environmental factors like cigarette smoke or alcohol, or if the second BRCA1 or BRCA2 gene starts to mutate.
How common are BRCA genetic mutations?
If you are of Ashkenazi Jewish descent, the chances of carrying a BRCA1 or BRCA2 mutation are as high as one in 40. However, for the general population, BRCA mutations occur in around approximately one in 400-800 people.
Can genetic testing determine my risk of pancreatic cancer?
Genetic testing can’t predict whether or not you will develop pancreatic cancer, but it can show whether you are at increased risk of the disease. The Myogenes hereditary cancer test – which is one of the most comprehensive tests currently available – analyses 98 genes from your DNA (including BRCA1 and BRCA2) and can identify your risk of 25 types of hereditary cancers, including pancreatic, breast, ovarian, prostate and colon. It uses a simple saliva test which is analysed at a CLIA-certified laboratory. The test can be particularly helpful for people with a family history of cancer or those in ethnic groups that have an increased risk of certain types of cancer.
Will knowing that I have BRCA mutations make a difference to my treatment?
Knowing that you have BRCA mutations can help you to make informed decisions about your health, such as having regular screening to detect cancer early or avoiding alcohol and red or processed meat, both of which are known to increase your risk of the disease. You may also wish to quit smoking or lose weight, as these too are risk factors.
If you do develop pancreatic cancer, you may be given a form of targeted therapy called PARP inhibition. Recent phase III clinical trials of PARP inhibitors showed promising results in patients with BRCA mutations who had pancreatic cancer. Undergoing molecular profiling of a pancreatic tumour can provide even more tailored treatment.