Reviewed by: Kalisi Logan, Genetic Counselor
Written by: Gene Lazuta
For hundreds, maybe even thousands of years, people observed that offspring inherited certain traits from their parents. Whether it was the brown eyes of a child, or the short hair of a puppy, it was obvious that somehow newborn offspring were a mix of the attributes that made their parents unique.
In 1866, Augustinian monk Gregor Mendel published the results of the eight years he spent studying pea plants in his garden. The attributes he tracked, which included things like smooth or wrinkled pods, followed a predictable pattern, implying that there was some mechanism controlling how heredity worked. Exactly what that mechanism was remained a mystery until 1962, when James Watson, Francis Crick, and Maurice Wilkins shared a Nobel Prize for their work in discovering the famous “double helix” structure of DNA (deoxyribonucleic acid), the molecule that contains the hereditary “blueprint” for cells.
By 2003, the Human Genome Project, a 13-year global scientific effort coordinated by the U.S. Department of Energy, National Institutes of Health, and other research organizations around the world, identified all of the approximately 20,500 genes in human DNA. The project is estimated to have cost over three billion dollars, and the information it generated is still being studied by researchers to this day. Now, anyone can have portions of their genetic code mapped at a cost of a couple of hundred to a couple of thousand dollars, depending on how many genes are targeted.
While this three-event history of the science of genetics skips over thousands of important discoveries made by hundreds of thousands of researchers who contributed to this timeline, the crucial points of genetic heredity are:
1. People recognized that members of families shared certain attributes
2. Science helped us understand the fundamentals of how all living things are built and the importance of heredity
3. The combined observations of a family’s history with modern genetic testing reveals the likelihood that an individual may experience certain health issues, such as some forms of cancer, during their lifetime
This is where Kalisi Logan, MS, comes in. Logan is a genetic counselor in UT Health Austin’s LIVESTRONG Cancer Institutes, and it is her job to help patients understand their cancer risks by using carefully gathered family histories to help them better manage their health over time.
“A genetic counselor is a professional who has been trained both in medical genetics and in counseling,” Logan explains, “which means that we do more than just genetic testing. Though genetic counselors can work in many different areas, I specialize in cancer care. So after the genetic testing is done, there’s more work to do, especially for my patients who have tested positive for hereditary cancer. That means that they have an increased risk to develop a cancer, so working together, we can formulate a plan that will help them make changes to the way they manage their health care that may reduce that risk as much as possible.”
Logan is quick to point out that a positive result in a cancer screening does not automatically mean that a person is going to get cancer. Additionally, she stresses the difference between a hereditary risk of cancer and familial cancer as the distinction between the two is important. A hereditary risk of cancer is identified by certain genes or gene mutations, such as the famous breast cancer genes, BRCA1 or BRCA2, which are associated with higher risks of breast or ovarian cancer in women and prostate cancer in men. Familial cancer is cancer that seems to run in families, but that does not have any specific, identifiable gene or gene mutation—or at least not any that can be tested for today.
“In a typical appointment,” Logan says, “I go through a patient’s personal medical history, and I also take a very detailed family history. I will ask what cancers the patient and their relatives were diagnosed with and at what age. I will also ask about family members who never had cancer because this information still affects their risk assessment.”
Women who test positive for an elevated risk of breast cancer can begin mammograms at a younger age, request advanced imaging tests such as MRIs, and increase the frequency of routine screening tests to help better monitor their personal health trajectory. This will ensure that if a cancer should occur it is diagnosed and treated early, when the likelihood of a positive outcome is greatest.
“The more you know and the sooner you know it,” Logan concludes, “the more informed your decisions will be. Which is why, at the LIVESTRONG Cancer Institutes, we encourage women to think of their family history, and genetic testing (when it is appropriate), as important parts of an active preventive health strategy. We work with family medicine and other medical providers in the community to deliver this important service as a supplement to a comprehensive preventive approach that leverages a range of tools that focus on helping women and men better understand and address their own unique risk and circumstances. And medical researchers are discovering new genes, and new tests every day. As an oncology genetic counselor, I am here to help my patients access the information and the services they need to make the best decisions possible for themselves and their families.”
To make an appointment with Kalisi Logan to discuss how oncology genetic counseling could help you learn more about your individual risks as well as preventive and/or treatment approaches, please call 1-833-UT-CARES or visit us here.