Genetic Testing

What is the BRCA gene?

Genes are pieces of DNA that form the code for our bodies much like the code written for computer programs. If something in the code is altered, the program will not work. Scientists discovered the BRCA1 gene in 1994 and the BRCA2 in 1996. Everyone (men and women) has a BRCA gene.

A functioning BRCA gene suppresses or keeps cancer cells from forming. When there is a break or mutation in the gene, cancer forms easier and at an earlier age. BRCA gene mutations are associated with an increased risk of breast, ovarian, prostate and pancreatic cancers. Abnormalities in the BRCA gene account for 7-10% of breast cancer. Another 15% is familial meaning there is an increased number of men or women with breast or ovarian cancer but the BRCA mutation is not found. The cause of the remaining 75% of breast cancer cases is not fully understood and called “sporadic.”

Who needs DNA testing?

Several factors in the family history make a person a candidate for genetic testing:

  • Breast cancer diagnosis before the age of 50
  • A family history of ovarian cancer at any age
  • A male family member with breast cancer
  • A family member with a breast cancer in both breasts (the same time or at two separate times)
  • A family member with breast and ovarian cancer
  • Ashkenazi or Eastern European Jewish ancestry

How is genetic testing done and are there any drawbacks?

Any DNA testing for possible genetic disorders is done with a simple blood test. The single tube of blood is sent to a specialized lab (Myriad Genetic Laboratories). A complicated series of tests are performed and rechecked over a 2 to 3 week period before the information is returned to my office.

I cannot tell this information to anyone, including the insurance company, unless you allow. The insurance cannot increase your premiums and cancel your policy because of this information. There are several state and federal laws that protect this information.

Why does the information matter?

BRCA1 mutation gives up to an 85% chance of breast cancer and a 45% chance of ovarian cancer. BRCA2 mutations give up to a 65% chance of breast cancer and a 26% chance of ovarian cancer. Having a second breast cancer after surviving the first cancer can occur in up to 65% of patients. Males with the BRCA abnormality have a 6% chance of breast cancer which is times the general male population. Men also have an increased risk of earlier prostate cancer.

This information is very important in planning surgery because the planned lumpectomy might significantly change. If a woman has the BRCA gene mutation, a bilateral or double mastectomy would be recommended due to the high risk of a second breast cancer. Surgery to remove the ovaries might also be considered to decrease the ovarian cancer risk. It has been found that removing the ovaries cuts the chance of breast cancer in half. All of this information will be discussed in the office visit.

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Medical Center of Plano

3801 West 15th Street
Suite 150B
Plano Texas 75075 214.501.5427 - Office
214.501.5429 - Fax