Pancreatic cancer: arguably the most haunting pair of words in the medical world. Numerous high-profile people have succumbed to pancreatic cancer and brought awareness to the disease. These cases have demonstrated a stealthy disease, which is often discovered with few treatment options available.
Between 1% and 2% of people will be diagnosed with pancreatic cancer in their lifetime. Most cases are diagnosed after the age of 50 years, with an average at-diagnosis age of 70 years. The five-year survival rate remains among the lowest of all forms of cancers. And, unfortunately, many cases are identified when the cancer has already spread outside of the pancreas and into other parts of the body, which makes treatment more difficult.
Naturally, people wonder why pancreatic cancer occurs. There are many different factors that can influence one’s risk for pancreatic cancer: smoking tobacco, chronic pancreatitis and diabetes among others. Similarly, family history and genetics can play a role in some cases of pancreatic cancer. Approximately 10% of individuals diagnosed with pancreatic cancer have a blood relative with pancreatic cancer. Thus, we suspect that some individuals are born with genetic risk factor(s) for pancreatic cancer.
Do our genes play a role in pancreatic cancer?
In case you need a refresher on genetics: our bodies are composed of billions of tiny cells. Every single cell contains a copy of our genetic makeup that comes from our parents. Our genetic makeup provides recipes/instructions for every task our cells need to complete. Each recipe or instruction is called a gene.
There are thousands of different genes that help determine traits such as height, hair color and eye color to name a few. Each gene is a long chain of chemicals that the cells use to create a protein, just as a recipe provides instructions to create a food. These proteins carry out various jobs within the cell. Everyone inherits two copies of every gene: one copy of every gene from their mother and one copy of nearly every gene from their father. The cells typically use both copies of a gene interchangeably to complete tasks in the cell. Genes are named with three to six letters and/or numbers, i.e. BRCA1, STK11 or CDKN2A many others.
We now understand that some genes protect us from cancer. For instance, the BRCA1 and BRCA2 genes are very important genes that constantly protect people from developing breast cancer, ovarian cancer, prostate cancer, pancreatic cancer and possibly other types of cancer. These genes are constantly being used by cells throughout the body, particularly in specific parts of the body.
Hereditary predispositions to cancer
Researchers have established that we all inherit genes from our parents, which defend us from cancer. Scientists and researchers have also established that some families develop more cancer than other families. By studying families with increased rates of cancer, we have learned that some families are impacted by a hereditary predisposition to cancer. People with a hereditary predisposition to cancer are more susceptible to certain types of cancer because of a single genetic risk factor. Individuals with a hereditary predisposition to cancer don’t usually show any obvious signs or symptoms of the cancer risk; they can grow and learn just as anyone else. Oftentimes, people with a hereditary predisposition to cancer are unaware of the condition until they (or their family members) undergo genetic testing.
It is important to understand that most people with cancer do NOT appear to have a hereditary predisposition to cancer. As I stated earlier, approximately 10% of individuals with pancreatic cancer will be found with a genetic mutation associated with a hereditary predisposition to cancer. This implies that we do not identify a hereditary predisposition to cancer in the remaining 90% of cases of pancreatic cancer.
Genetic testing and pancreatic cancer
Genetic testing is available to identify individuals with these uncommon hereditary predispositions to cancer. This testing is designed to read through an individual’s genetic code and look for changes in the genes. This testing can usually be performed on blood or saliva and focuses on genes associated with cancer.
The results of genetic testing can provide information about someone’s cancer risk and guide their cancer screening options. If genetic testing identifies a gene mutation, we provide them with risk estimates for various cancers. These risk estimates are based on families with similar mutations in the same genes. For instance, if genetic testing identifies that someone carries a mutation in the BRCA1 gene, we know that their risk for breast, ovarian, pancreatic and prostate cancer is higher than the average person’s risk for those cancers.
| Gene name | Lifetime pancreatic cancer risk | Other cancer risks |
| BRCA1 | ~5% | breast, ovarian, prostate |
| BRCA2 | 5%-10% | breast, ovarian, prostate |
| STK11 | 15% or greater | colon, small intestine, breast and others |
| CDKN2A | 15% or greater | melanoma and others |
| PALB2 | 2%-5% | breast, ovarian |
| MLH1 | 5%-10% | colon, rectal, uterine and others |
| MSH2 | 5%-10% | colon, rectal, uterine and others |
| MSH6 | 5%-10% | colon, rectal, uterine and others |
| ATM | 5%-10% | breast |
| MEN1 | 20% or greater (neuroendocrine type) | pituitary gland, parathyroid gland and others |
Why perform genetic testing for pancreatic cancer susceptibility?
Many patients ask if there’s any benefit to genetic testing for pancreatic cancer. Thanks to recent advances, individuals with specific gene mutations may be candidates for pancreatic cancer screening. For instance, people with mutations in certain genes (STK11, CDKN2A, ATM and BRCA2) can consider pancreatic screening tools such as contrast-enhanced MRI/magnetic resonance cholangiopancreatography (MRCP) and/or endoscopic ultrasound (EUS). Individuals with mutations in some of the other genes associated with pancreatic cancer may also consider screening for pancreatic cancer and can discuss options with their health care providers.
Genetic testing also provides information regarding risks for other cancers may prompt more intensive cancer screening for other parts of the body. Importantly, genetic testing may also provide information for family members. If a significant gene mutation is identified in an individual, we always make an effort to identify other relatives who may share the same genetic risk factor. Lastly, individuals with a diagnosis of pancreatic cancer and specific gene mutations might be eligible for specialized therapies targeting the gene mutation.
Thus, if you have a family history of pancreatic cancer in a close relative (parent, sibling or child) you can consider asking a doctor for referral to Northside Hospital Cancer Institute Cancer Genetics Program for a genetic counseling appointment.
Key points
Genetic testing cannot determine if or when someone will develop cancer. It will not determine what type of cancer someone will develop. However, genetic testing can provide critical risk information in approximately 10% of cases of pancreatic cancer, which is useful for patients and family members facing pancreatic cancer. With more time and research, we hope that more and more people will be able to identify pancreatic cancer earlier and receive life-saving treatments.
Learn more about pancreatic cancer treatment at Northside.
