Genetic Testing at Dana-Farber Cancer Institute

Frequently Asked Questions About Genetic Testing

What are genes?

Genes are individual units of inheritance made of DNA. We all have two copies of each gene; we inherit one copy from each of our parents and pass one copy on to each child. The exact DNA sequence of a gene is a code with instructions to make a functioning protein (like a recipe). Changes to the DNA code can cause the gene not to work and stop its protein from being made.

What is genetic testing?

Genetic testing is a process that looks for alterations in a person's genes. Alterations in certain genes may lead to an increased risk of cancer. Therefore, genetic testing results may be helpful in tailoring cancer screening recommendations.

Genetic testing involves sending a blood sample to a specialized lab for analysis. Results are returned to the ordering physician and genetic counselor, who then discloses them to the patient and arranges appropriate follow-up care.

Who is a genetic counselor?

Genetic counselors are trained licensed professionals who have earned a Master's degree in genetic counseling from an accredited program. Cancer genetic counselors specifically counsel patients about inherited cancer syndromes, the chance they might carry a gene in a form that confers increased risk of specific inherited cancer syndromes, the mechanics of genetic testing, the patient's chance of having an inherited susceptibility to cancer, and the implications of being found to carry or not carry a genetic risk for cancer.

The role of a genetic counselor is to assist individuals and families in understanding genetic disorders. Genetic counselors:

  • Gather a three-generation family history
  • Obtain informed consent for genetic testing when appropriate
  • Discuss options for risk management and family planning
  • Provide, or refer individuals for, psychosocial support as needed

Genetic counselors often help to interpret confusing or uncertain test results, and also educate patients and providers on new testing options. For this reason, genetic counselors may maintain contact with patients over time.

What should I expect from meeting with a genetic counselor?

During the visit, your genetic counselor will take a detailed family history in order to evaluate the likelihood that you could have an inherited predisposition to cancer. Features of a family history that suggest a hereditary susceptibility include:

  • Cancer diagnosed at young ages
  • Cancers spanning several generations in a family
  • Individuals with multiple cancer primaries (original sites, where cancer first starts to grow)

The genetic counselor may then discuss the option of testing and will explain the relevant gene(s) and associated syndrome in terms of cancer risks and medical management issues. Common concerns of genetic testing, including issues of insurance discrimination and confidentiality, will be discussed. Possible results of genetic testing, as well as the cost and logistics of testing, insurance coverage, or options if insurance does not cover, will also be reviewed. Your genetic counselor will help to guide you in making the best decisions regarding genetic testing for yourself, as a decision to undergo genetic testing or not is truly a personal decision.

What personal information is needed for my visit?

Information regarding personal and family cancer history – including the specific cancer(s), age(s) at diagnosis or information about pre-cancerous conditions such as colon polyps – and copies of personal or family genetic test results are requested for your visit. Other medical records such as pathology reports, surgical reports, or summary notes) are often useful. Also helpful are prior pathology reports.

Genetic Counseling for Cancer Risk: What to Expect

Genetics counselor Kathy Schneider, MPH, LGC, describes what to expect from a genetic counseling visit, who should consider genetic counseling, and how it can be helpful in understanding risk for certain types of cancer based on personal and family history.

How can I reduce my cancer risk?

We recommend general guidelines for a healthy lifestyle as endorsed by the American Cancer Society and the National Cancer Institute, as these may also help reduce your risk for developing cancer.

Many studies have shown the importance of physical activity for overall health, maintaining weight, and lowering the risk of many types of cancer and other conditions. Most experts recommend getting at least three to five hours of exercise per week, but any steps towards increasing activity level will provide some benefit. Aerobic exercise involves raising the heart rate; examples include brisk walking, climbing stairs, jogging, swimming, and taking an exercise class. Before beginning a new exercise program, it is a good idea to talk with your doctor.

Learn more about reducing your cancer risk through exercise

Stop smoking. It is never too late. For smokers, kicking the habit is one of the single most important steps to reducing the risk of cancer and other serious diseases. Quitting smoking can be a challenge, and having support is a key to success. We can provide information about smoking cessation programs that should be available in your area. Your doctor can give you guidance; we also recommend the QuitWorks program offered by the Massachusetts Department of Public Health.

The American Cancer Society recommends limiting alcohol intake to fewer than four servings per week. A serving is defined as 12 ounces of beer, 5 ounces of wine, or 1 1/2 ounces of spirits.

Sun Protection
Wearing protective clothing and using sunscreen provide protection against harmful ultraviolet (UV) rays. Some forms of skin cancer are very common, but protecting yourself from the sun will reduce the risk of even the most serious types. Other risk-reducing steps include avoiding the sun during the midday peak exposure hours (between 10 a.m. and 2 p.m.) and wearing sunglasses and a hat. Tanning booths are not safe for anyone.

One of the most important factors in maintaining overall health is to eat a nutritious, heart-healthy diet. This means consuming plenty of fruits and vegetables, whole grains, and lean protein – and limiting processed foods, saturated fats, and sugar. Saturated fats are found in meats, full-fat dairy products, and many processed foods. Following a heart-healthy diet will also help you maintain a healthy weight, lowering the risk of several cancers. Be sure to talk with your doctor about any specific dietary concerns or questions you may have. We recommend Dana-Farber's Nutrition Services web section as a great place to start for ideas and recipes.

Videos about Genetic Testing

In the videos below, Dana-Farber cancer genetics specialists provide answers to a variety of questions about specific genetic tests, interpreting test results, and genetic risk for cancer.

What is Panel Genetic Testing?

Genetic counselor Jill Stopfer, MS, LGC, describes panel genetic testing: what it is, how it compares to other types of testing, and how it may help individuals who may be at risk for certain types of cancer based on their personal and family history.

What Are Germline and Somatic Mutations?

Huma Rana, MD, Clinical Director of the Center for Cancer Genetics and Prevention describes the difference between germline and somatic mutations, and implications for cancer treatment.

What is Li-Fraumeni Syndrome?

Judy Garber, MD, MPH, Director of the Center for Cancer Genetics and Prevention, describes Li-Fraumeni syndrome, a hereditary disorder that increases the risk of developing several types of cancer, and ways that individuals and families can manage this diagnosis.

What is a Variant of Uncertain Significance (VUS)?

Genetics counselor Erica Vacarri describes what a VUS diagnosis means, and how this may or may not relate to risk for certain types of cancer.

What is Mosaicism?

Genetics counselor Kathy Schneider, MPH, LGC, describes mosaicism, and how genetic counselors assess the risk for cancer for individuals found to have mosaicism.

Mosaicism vs. Circulating Tumor Cells

Genetics counselor Kathy Schneider, MPH, LGC, describes the difference between mosaicism and circulating tumor cells.