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What's in a name? Genetics vs genomics

October 06, 2015 | by CTCA

Genetics
The words “genetic” and “genomic,” for example, are often used interchangeably, even though they have very distinct meanings, especially when it comes to treating cancer. Learn the critical differences between the two and what they mean to cancer care.

Cancer care has made enormous strides over the past decade, driven in large part by DNA-related discoveries. But confusion persists among the general public over what it all means. That misinformation may cloud patients’ understanding of how available treatments can benefit them, and may even deter them from pursuing certain options. The words “genetic” and “genomic,” for example, are often used interchangeably, even though they have very distinct meanings, especially when it comes to treating cancer.

Genetics

Genetics refers to the inherited traits passed from one generation to the next through the gene pool. With genetic testing, scientists study the molecular makeup of a particular patient, identifying abnormalities or predispositions he or she may have been born with, and how they might affect the risk of disease and other health implications.

For instance, the BRCA1 gene has been linked to an increased risk for breast cancer. Genetic testing was thrust into spotlight in 2013, when actress Angelina Jolie announced she had undergone a preventive double mastectomy after discovering she carried the BRCA1 gene mutation. A person who inherits an altered version of the BRCA1 and/or BRCA2 gene(s) has a higher risk of developing breast and ovarian cancer.

Genetic testing is not for everyone. It is typically recommended for people with a family history of cancer or other illnesses, including a history of:

  • Breast, colon or uterine cancer diagnosed under age 50
  • An inherited gene mutation
  • Ovarian cancer diagnosed at any age
  • The same cancer type diagnosed in two or more close family members
  • The same type of cancer in several generations of the family

Genomics

While genetics involves the study of a patient’s molecular composition, cancer-related genomics involves decoding the DNA structure of tumor cells. Genomic testing, for example, can reveal the characteristics that are driving a tumor and telling it how rapidly to grow and where to spread. The tests can also uncover abnormalities in the cancer that may be influenced by certain drugs.  

Because both fields of study involve examining the influences of genetic abnormalities, people—even some doctors—often mix up the two terms. “What’s important here is to understand we are talking about two very different types of DNA,” says Dr. Maurie Markman, President of Medicine and Science at Cancer Treatment Centers of America® (CTCA). “I personally would use the term ‘genetic’ to refer to the genes that are present in an individual since birth, and I’d use ‘genomic’ to describe the genes that might be unique in a tumor. That is certainly not a convention that is used by everyone, and that adds to some of the confusion.”

As doctors use genetics to learn more about diseases caused by a single gene and genomics to better understand specific gene mutations and complex diseases like cancer, it can lead to earlier diagnoses, new interventions and targeted treatments. Think of it as fighting cancer with a missile rather than a bomb.

This is especially true in advanced genomic testing, which elevates the standard tumor test with gene-mapping analyses. The tests may be an option for patients with hard-to-treat cancers and those with tumors that did not respond adequately to conventional therapies. This type of personalized care, often called precision cancer care, examines the tumor’s molecular makeup to identify whether more appropriate treatments may be available. “By finding the abnormalities present in the cancer, you may be able to hone in on that abnormality and make the treatment more precise,” says Dr. Markman.