Meet our doctors: Thomas Slavin on genetic testing

August 27, 2015 | by Jeanne Kelley

Thomas Slavin, M.D. Thomas Slavin, assistant clinical professor in the Division of Clinical Cancer Genetics at City of Hope, discusses genetic testing and why he chose genetics as a career.

People with a family history of cancer often want, or need, to know whether they have a gene mutation linked to that cancer. For that, they seek genetic testing, involving a blood sample that is analyzed for specific gene abnormalities.

Thomas Slavin, M.D., a geneticist and assistant clinical professor at City of Hope, typically works with patients – primarily breast, ovarian or colorectal cancer patients – who have a hereditary predisposition to cancer. Most are part of City of Hope's large Hereditary Cancer Registry and are working with a genetic counselor. Slavin, the counselor and the patient use the patient's history and genetic information to inform testing and make treatment plans.

Here, Slavin explains why he chose such a complex and rapidly involving field.

Why did you choose the field of genetic testing?

It has been an interest of mine since I was very young.  When I was in middle school, I wrote to the American Society of Human Genetics requesting information about careers in genetics because I’ve always found it intriguing that one little mutation in a single gene can be life-changing for a family. After pursuing residencies in both pediatrics and medical genetics and completing a board certification in molecular diagnosis, I became particularly interested in the rapid advances in genetics sequencing and the newfound ability to make detailed molecular diagnoses on individuals.

What inspires you to do the work you do?

Genetics is a unique field, in that the whole family is treated, not just a patient. The research community is continually learning about molecular pathways, and altering pathways and the potential for gene therapy is inspiring. Understanding how to use this new powerful genetic information to reduce or remove disease burden in the affected individual and their family members is exciting and rewarding. In other words, my job boils down to two things: Can we find the cause of the cancer predisposition, and if so, how can we keep an individual free from developing cancer once we’ve identified genes linked to cancer? If a genetic change is found early on, the potential exists to reverse destiny.

Genetic testing is still fairly new. How has it changed the most over the past five years?

Things have drastically changed in the past five years. It’s 98 percent different. I attribute this to two things – one is the low cost, high throughput, next-generation sequencing techniques, and two is the Supreme Court’s ruling that genes cannot be patented. Combined, they 've created an explosion in hereditary cancer genetics testing, since now all labs can offer testing with affordable next-generation sequencing and there are no restrictions on patenting genes like BRCA1 or BRCA2.

This launched the next era of multigene panels, and now we routinely test  15 to 40 genes for hereditary cancer susceptibility in most individuals that we counsel. This has therefore led to many new discoveries and cancer associations that we have yet to understand.

What are the most exciting developments underway?  

The most exciting new developments in my field involve better understanding of all the cancer types associated with particular gene changes, tailoring screening to individuals based on their family history and genetic susceptibility, and learning how to manipulate pathways in those carrying a mutation (on the horizon).

Since coming to City of Hope, I have been collaborating with Jeffrey N. Weitzel, M.D., and Susan Neuhausen, Ph.D., to develop new tools for assessing hereditary cancer predisposition. Our team is looking for new hereditary susceptibility markers for pancreatic and gastrointestinal cancer by sequencing patients with large family histories of these cancers with no known explanation. This endeavor will leverage the large hereditary cancer registry (data on more than 14,000 families) developed by Weitzel.

Extraordinary new developments are always underway at City of Hope. I believe this is the best clinical genetics research program in the world. I look forward to making substantial contributions to the clinical research arms of the Division of Clinical Cancer Genetics.

What are your goals and priorities for your work at City of Hope?

My main goal and priority is to be a clinical expert in hereditary cancer genetics and to educate others in the area. City of Hope offers a yearly genetic cancer risk assessment course developed by Weitzel and Kathleen R. Blazer, M.S., that teaches clinicians to practice genetic cancer risk assessments. It’s an intensive course in which attendees develop expertise in evaluating people and families for cancer genetic susceptibility, as well as screening and management to keep people free from cancer. The program has now trained more than 500 national and international physicians, genetic counselors, Ph.D.s and nurses from around the world.


Learn more about becoming a patient or getting a second opinion at City of Hope by visiting our website or by calling 800-826-HOPE (4673). You may also request a new patient appointment online. City of Hope staff will explain what's required for a consult at City of Hope and help you determine, before you come in, whether or not your insurance will pay for the appointment.


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