Understanding Genetic Testing for Breast Cancer

The Comprehensive Breast Center at Staten Island University Hospital offers genetic counseling services to individuals who may be at risk for a hereditary cancer syndrome based on their personal and/or family history of cancer.  Our experts provide personalized risk assessments, education and the opportunity for genetic testing when appropriate.  

Sporadic vs. Hereditary Cancer

Cancer is a disease of the genes.  Most cancers develop as a result of genetic damage sustained over a lifetime. When genes acquire defects that impact the cells ability to grow and divide properly or to repair damaged DNA, cells are permitted to divide uncontrollably to form tumors.  Cancers that occur due to genetic changes acquired over time are considered to be sporadic and are usually associated with an older age of onset (greater than 45 years old).  Approximately 70 to 80 percent of all breast cancers are considered to be sporadic and, therefore, are not thought to be associated with the genes we inherit from our parents.    

Cancer that results form genetic changes that are passed on from one generation to the next is considered hereditary.  Approximately 5 to 10 percent of all breast cancers fall into this category.  Factors that may indicate a cancer is hereditary may include, young age at the time of diagnosis (less than 45 years old), family history of cancer and ethnicity.  

Genes Associated with Increased Risk for Breast Cancer

A number of genetic defects have been found to be associated with hereditary breast cancer.  These inherited genetic changes can result in an increased risk for developing breast cancer, but do not guarantee if or when cancer will develop.

The most common genes known to be associated with hereditary breast and ovarian cancer are the BRCA1 (breast cancer gene 1) and BRCA2 (breast cancer gene 2) genes.  Abnormalities in these genes account for approximately 80 percent of hereditary breast and ovarian cancer cases.  The discovery of the breast cancer genes in the early 1990s has greatly influenced our understanding of the genetic basis of inherited breast and ovarian cancer.  Scientists continue to work to understand the significance of different alterations in the BRCA genes as well as other genes known to be associated with hereditary breast cancer. 

Deciding on Genetic Testing for Breast Cancer

Genetic testing should be considered for individuals at high-risk due to a personal and/or family history of cancer.  You might fall into this high-risk category if:

  • You or a close relative developed breast cancer before age 45
  • You have 2 or more close relatives with breast cancer on the same side of the family
  • You have breast cancer in more than one generation in your family
  • You have a personal and/or family history of ovarian cancer
  • You have family members who have had pancreatic or early onset prostate cancer (diagnosed before age 50)
  • You are of Ashkenazi (Eastern European) Jewish ancestry
  • You have a relative who has a known alteration in a gene associated with hereditary cancer

The Genetic Counseling Process

If you are considering genetic testing due to a personal and/or family history of cancer, you may have many complex questions and concerns you would like to discuss prior to moving forward.  A genetic counselor specializing in cancer genetics can meet with you to address your concerns and determine whether your family history suggests the presence of a hereditary cancer syndrome.  

The genetic counselor will collect a detailed cancer-focused personal and family history.  Using this information the counselor will work with you to:

  • Assess your risk for developing cancer
  • Discuss the option of genetic testing when appropriate
  • Review the risks, benefits and limitations of genetic testing including:
    • Accuracy of the test
    • Implications of test results 
    • The turn-around time for results
    • Financial aspects of the testing
    • Concerns regarding genetic discrimination
  • Provide you with educational materials and emotional support

To make an appointment or for more information on cancer genetic counseling, please contact us at 718-226-6230.