Transitioning from Germline to Somatic Genetics

Heather Mikesell, MS, CGC
Heather Mikesell, MS, CGC

Heather Mikesell is a licensed and certified genetic counselor. She graduated from the University of Pittsburgh Graduate School of Public Health with MS of Science in 1991. She worked for 20 years as a clinical genetic counselor in a variety of areas including cancer, general, prenatal genetics, and specialty clinics. She began an industry career at Myriad Genetics in 2011 and now works at Guardant Health.

Germline genetics is the basis of what we learn as genetic counselors. I have fond memories of completing Punnett squares, learning about chromosome translocations, uniparental disomy, and mitochondrial genetics. Where would I be without pedigrees demonstrating how diseases are being passed through families and without having discussions with patients and healthcare providers? These were some of my concerns when I switched to somatic cancer genetics one year ago.  

I did not know much about the world that awaited me. I only knew after 30 years in the field, I was ready for a new challenge. I also knew that liquid biopsy is like prenatal testing, but instead of analyzing fetal DNA in maternal blood it analyzes DNA shed from tumors (circulating tumor or ctDNA) in the blood. When the opportunity to work at Guardant Health came, I jumped at it. Head-first. Into the deep end.

The Challenges

I have a love of learning and diving into the world of somatic cancer genetics certainly fostered this love, but it has been challenging. It required me to learn about lung cancer – not my bread and butter cancers of breast, ovarian, and colon. It required me to focus my knowledge on how gene mutations drive cancer by altering the biochemical pathways in a cell. I also had to learn how new treatments target these mutations to give patients with advanced cancer a longer life. Some days the most challenging part of the job is trying to pronounce the drug names! You would think after learning complex names like trichilemmoma I could easily wrap my mouth around names like “panitumumab” and “larotrectinib”, but it took a while for this to feel normal.  

The biggest challenge was letting go (a little bit!) of germline cancer genetics. Every time I saw a lab report with an ATM or BRCA mutation I would wonder – is this patient a germline carrier? Have they been tested? What is their clinical history? Luckily, the somatic world does not ignore the germline world. In many somatic labs, when a mutation is identified that could be germline, the healthcare provider is alerted and testing at a validated germline lab is suggested.

The Benefits

Working in somatic genetics has broadened my view of how genetic information may be used to treat disease. I now have an additional lens to use when applying genetics knowledge. I have learned a new way to speak about genetics and apply it to patient care. I also have a new way to educate healthcare providers. Genetics isn’t just about recurrence risks and family planning, it is also about treating patients to improve their outcomes. This is by far the best part of my job. When I help a provider understand how next generation sequencing of a tumor may dictate treatment of a patient’s cancer, and how liquid biopsy may shorten a patient’s time to treatment and possibly save them from another biopsy, it is as rewarding as helping a family understand their genetic disease or helping a provider realize the benefits of genetic testing in their practice.  

I view myself as a genetics ambassador. One of my roles is to educate others about the benefits of understanding the genetics of disease. I have seen genetics transform healthcare, and I am seeing it transform treatment for cancer. Every time I work with a provider and they explain how our testing changed the quality of life for a patient, my cup gets filled. Even though I’m still early in my journey to fully understand cancer somatic genetics, I wonder where this new way of looking at genetics will take me in the future.  

If you are looking for a new challenge, want to explore how genetics knowledge may be used to treat more common diseases, and don’t mind remembering some of the pathways from biochemical genetics, exploring a role in somatic genetics could be right for you. There are many labs in the somatic cancer space  who employ genetic counselors and have great career opportunities. Working in somatic genetics is not abandoning all you have learned; it is the opposite. It helps you truly understand how genetics affects disease. It is a fascinating world, and I am grateful I took the chance to explore it.

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