Cancer and Genetics: Who should be tested?

 
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Who should consider genetic testing?

The purpose of genetic testing for hereditary cancer syndromes is to identify if there is a genetic variant in an individual that increases their chance of developing cancer. Testing is targeted at certain genes that have been identified as having a link with cancer. As the field of cancer genetics expands, more genes have been found to be linked to particular cancers.

You should consider genetic testing if you have been diagnosed with cancer and have one of the following:

  1. Multiple cancers

  2. If you are less than 50 yo when you are diagnosed with breast, colon, or endometrial cancer

  3. Ovarian cancer

  4. Metastatic breast cancer

  5. Male breast cancer

  6. Metastatic prostate cancer, or a Gleason score of 7 or greater

  7. Pancreatic cancer

  8. If you have abnormal pathology with colorectal or endometrial cancer (MSI/ICH)

You should consider genetic testing if you have a strong family history of any of the following:

  1. Multiple individuals on the same side of the family with cancer

  2. A close relative with ovarian cancer

  3. A close relative with breast cancer diagnosed at age 50 or younger

  4. A close family member with colon cancer or endometrial cancer diagnosed at age 50 or younger

  5. A close relative with pancreatic cancer

  6. Multiple members on one side of the family with breast cancer (3 or more)

  7. Multiple members on one side of the family with prostate cancer (especially diagnosed at a younger age

  8. If a family member has been identified as having a genetic mutation that increases their risk of developing cancer.

Why should we test for genetics?

  1. If certain genes are identified, a targeted treatment option could be available for metastatic breast cancer, ovarian cancer, or prostate cancer patients

  2. Genetic testing can help identify if you were at increased risk for developing cancer

  3. Genetic testing can help determine if you are at risk for developing other cancers

  4. Genetic testing can help your family determine if they are at increased risk for cancer. 

  5. If you have a genetic variant that increases your risk of cancer, screening can be tailored to identify cancer early

What are hereditary cancer syndromes?

Hereditary cancer syndromes are genetic predispositions to cancer that are passed down through families.  Through sequencing the DNA, we can identify certain changes that are linked to an increased risk of cancer. 

Hereditary breast and ovarian cancer (HBOC): inherited mutations in BRCA1 and BRCA2 that increase the risk of breast and ovarian cancer as well as male breast cancer, prostate cancer, pancreatic cancer and melanoma

Lynch Syndrome: mutations in mismatch repair genes including MLH1, MSH2, MSH6, PMS2 that increase the risk of colorectal cancer. Mutations in these genes can also increase the risk of other cancers including endometrial, ovarian, breast, intestinal, pancreatic. 

Familial Adenomatous Polyposis (FAP): Mutations identified in the APC gene are associated with increased risk of colorectal cancer due to the formation of many polyps. Polyps usually start at an early age. The polyps are precancerous but develop into cancer over time. 

Cowden Syndrome: mutations identified in PTEN gene cause this syndrome which increase the risk of breast, endometrial and thyroid cancers. Individuals with cowden syndrome can also develop many benign tumors throughout the body.  

Li-Fraumeni Syndrome: a rare genetic condition caused by a mutation in TP53 which increases the risk of many cancers throughout a lifetime. Cancers may include breast cancer, sarcomas, leukemia, lung cancer, brain cancer, and/or adrenal cancer. 

Multiple Neuroendocrine Neoplasm (MEN) syndrome: this is a predisposition to developing tumors in endocrine glands (glands that secrete hormones).