What is hereditary (or inherited) cancer?
Most of the time, cancer develops by chance. There are a number of factors that can increase the chance that a person will get cancer; these are called risk factors. Different cancers have different risk factors. Aging is the biggest risk factor for all types of cancer. Another risk factor is having a family member with cancer. If one person in a family has cancer, close relatives of that person are often at increased risk of developing the same kind of cancer.
Most people with cancer have no family history of the same type of cancer. However, in some families there are several people who have the same type of cancer, often at young ages. These families may have a “hereditary” or “inherited” risk. About 10% of all cancers are hereditary. Hereditary cancers occur when a change in a particular gene (known as a mutation) is passed down from parent to child. Different gene mutations cause an increased risk of developing different types of cancer. In families that have a gene mutation, family members who inherit the mutation will often develop the same or related types of cancer, typically at earlier ages than usual. These families are said to have “hereditary cancer syndromes.”Back to top
What causes hereditary cancer syndromes?
Hereditary cancer syndromes are caused by mutations in certain genes. Genes are in every cell in our bodies. Genes come in pairs. One member of each pair comes from our fathers, and the other from our mothers. Genes are made of DNA and contain carefully spelled-out instructions for making substances called proteins, which help our bodies work properly. A change in the spelling of the gene can cause the gene to stop working correctly. Changes in the spelling of a gene are called mutations.
Each person has about 20,000 genes in every cell. Some genes are involved in cell growth, division, and repair of damaged DNA within cells. If someone has a mutation in one of these types of genes, he or she may have an increased risk of developing certain cancer(s) over his or her lifetime.Back to top
How are hereditary cancer syndromes inherited?
Both men and women can pass down genetic mutations that cause hereditary cancer syndromes. For most of these genes, it only takes a mutation in one copy of the gene to cause an increased risk for cancer. If you have a parent with a gene mutation that predisposes him or her to developing cancer, you may or may not inherit it. You have a 50% chance to have inherited the mutated gene from your parent. You also have a 50% chance not to have inherited the mutated gene.Back to top
How are gene mutations found?
It is possible to test for mutations in genes that cause hereditary cancer syndromes. Genes are made up of “bases,” which are like letters. These bases are arranged in a particular order, or sequence, much like the way letters are arranged in a particular order to form words. Genetic testing “reads” the bases in your genes, and compares them to what is known to be the normal spelling. Mutations are differences from the normal spelling of a gene.
Gene mutations can be found through a blood or saliva sample. It is best to start testing with a family member that has had a cancer type associated with the hereditary cancer syndrome of concern. Once a mutation has been found, other family members can be tested for that same mutation to learn their personal cancer risks. Sometimes stored samples from deceased relatives can be used to test for gene mutations.Back to top
What are the possible risks and benefits of genetic testing?
Risks and benefits should be considered before genetic testing. There are no risks of physical harm from testing other than that of a blood draw. However, genetic testing can have emotional effects, especially if a mutation is found. If a mutation is found, it can impact other family members. Some may not want to know these results.
There is a chance that someone could use your genetic test results against you. This is considered discrimination. The federal government and some states have laws that forbid using genetic test results against you. Under these laws, insurance companies cannot use your test results to deny you health insurance. They also cannot use your test results to raise the cost of your current health insurance. Some laws also prevent employers from using your test results as a reason to fire or not hire you.
Despite these laws, we cannot promise that no one will ever try to use your genetic test results against you. We do not know of any insurance or work problems for those who have had gene testing at MSK. Most insurers have covered the costs of genetic testing with no penalty to those being insured.
There are many possible benefits of genetic testing. It can give you and your family members a better understanding of your cancer risk. The results can help your doctor design a personal cancer screening program. They can also help you to decide about options for reducing cancer risk, including surgery to prevent it.
This is a personal choice, but your doctor, genetic counselor, and other healthcare professionals can help you make your decision. Regardless of whether you decide to have genetic testing, please feel free to contact us at the number below with any questions that you may have.Back to top
If someone does not want to have genetic testing, how can he or she manage his or her risk of cancer?
If a person does not want to have genetic testing, we recommend a personalized cancer risk assessment and screening plan. The cancer screening recommendations would depend on a number of factors, including family history of cancer and other risk factors.Back to top
Will the information about my genetic testing be kept private and confidential?
Yes, your genetic test results and your medical record will be kept private and confidential. When you registered at MSK, you were given a Notice of Privacy Practices. That document explains who has access to your medical record and what reasons they have to access to your record. If you would like to know more about MSK’s privacy practices, or if you would like another copy of the privacy notice, please let us know.Back to top
Will my insurance cover genetic counseling and testing?
Many insurance companies and managed care plans pay for both genetic counseling and testing. Check with your insurance provider before having genetic testing to see what they will cover.Back to top
Who should I call if I have questions?
If you have any questions or concerns, please contact MSK’s Clinical Genetics Service at 646-888-4050.Back to top