Most cancer cases begin with a mutation in the DNA. Most incidences of pancreatic cancer seem to be caused by sporadic (non-hereditary) or environmental factors such as smoking, obesity and increased age. While only about 10 percent of pancreatic cancers are considered familial or hereditary, researchers are interested in specific inherited genes. The following are disorders that are being studied for connections to pancreatic cancer.
BRCA 1 and 2 mutations are often related to inherited breast and ovarian cancer. However, the BRCA1 mutation may also cause a small increased risk of developing pancreatic cancer.
Mutations in the BRCA2 gene are associated with a 3 to 10 fold increased risk of developing pancreatic cancer. A mutation in this gene can be found in approximately 1% of individuals of Ashkenazi Jewish descent. This is higher than in other populations. People with BRCA2 mutations have a 10% lifetime risk of developing pancreatic cancer.
Cystic fibrosis affects the pancreas by causing pancreatic insufficiency and chronic pancreatitis. The risk of developing pancreatic cancer is 5 to 6 times greater in people who have cystic fibrosis compared to average risk.
Familial Adenomatous Polyposis (FAP)
FAP is a rare, hereditary form of colon cancer in which a person develops hundreds to thousands of noncancerous polyps in the colon that eventually become malignant. It is associated with higher rates of thyroid, small bowel, stomach and pancreatic cancers.
Familial Atypical Multiple Mole Melanoma (FAMMM)
FAMMM is characterized by younger age of melanoma diagnosis, many skin moles and multiple primary melanomas. People with FAMMM have a 13 to 22 fold increased risk of developing pancreatic cancer.
Hereditary Nonpolyposis Colorectal Cancer (HNPCC) or Lynch Syndrome
It is an inherited condition that is associated with 5% of colon cancer cases. Patients with HNPCC have approximately a 9 fold increased risk of developing pancreatic cancer.
Hereditary pancreatitis is a rare, inherited condition that usually starts before age 20. It is characterized by recurrent episodes of severe inflammation of the pancreas that can lead to chronic pancreatitis and approximately a 40-55% lifetime risk of developing pancreatic cancer. Individuals with hereditary pancreatitis who also smoke may develop earlier onset pancreatic cancer.
About 1-3% of patients with familial pancreatic cancer have inherited mutations in the PALB2 gene. Mutations in the PALB2 gene have also been associated with an increased risk of breast cancer.
Peutz-Jeghers Syndrome is characterized by polyps in the small intestine and pigmented spots on the lips and nose. Patients with this syndrome have a 11-36% risk of developing pancreatic cancer.
Having one or more of the genetic conditions listed above does not mean an individual will develop pancreatic cancer. Some individuals who develop pancreatic cancer do not have any of these risk factors. Individuals who think they may be at risk for pancreatic cancer should discuss this with their doctor and/or genetic counselor.
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