Physician Search Results

Colin C. Pritchard, MD, PhD

Dr. Pritchard works in the Department of Laboratory Medicine of UW Medicine, where he has helped develop UW-OncoPlex, an important test that benefits Seattle Cancer Care Alliance patients.

Dr. Pritchard's Resume


  • Assistant Professor, Laboratory Medicine, University of Washington School of Medicine
  • Associate Director, Clinical Molecular Genetics Laboratory, UW Medicine

Clinical Expertise

Cancer molecular diagnostics development for precision medicine and microRNA as blood-based biomarkers

Education And Training

  • Medical Education (MD &  PhD): University of Washington School of Medicine

More Information

  • Dr. Pritchard was recognized as a 2015 "Top Doctor" in Seattle magazine's annual survey. 
  • Read more about Dr. Pritchard's work at the University of Washington.

Dr. Pritchard's Story

For many cancer patients, one of the most important members of their treatment team is a doctor they will probably never meet: Colin C. Pritchard, MD, PhD. Dr. Pritchard works in the Department of Laboratory Medicine of UW Medicine, where he has helped develop an important test that benefits Seattle Cancer Care Alliance (SCCA) patients.

The test is called UW-OncoPlex. It allows oncologists to see which specific genetic mutation is causing a patient’s cancer. Armed with this diagnostic information, oncologists can then prescribe the treatment that is known to work best against that particular subtype of cancer. In this way, UW-OncoPlex can sometimes help spare patients from suffering the side effects of unnecessary treatments. And it enables oncologists to deploy the most effective agent before the cancer has additional time to grow.

A life-long quest

Dr. Pritchard’s interests grew naturally from his personal experiences with cancer. One of his grandfathers suffered from prostate cancer; the other died of leukemia. His father had metastatic prostate cancer for 15 years, and was also a colon cancer survivor before he passed away in 2008. And two of Dr. Pritchard’s cousins were diagnosed with breast cancer at a young age. “Clearly there’s a cancer predisposition in my family,” he reflects. “It weighed on my mind and influenced my decision to go to medical school.”

Dr. Pritchard enrolled in University of Washington’s demanding Medical Scientist Training Program, which resulted in both PhD and MD degrees—after nearly a decade of study.

A clarifying moment occurred early in the program, in 2000. Dr. Pritchard attended a lecture by Dr. Steve Friend, who at the time was co-director of an advanced drug discovery institute at Fred Hutchinson Cancer Research Center. “I got really excited,” Dr. Pritchard recalls. “He spoke about finding molecular signatures that could differentiate between types of breast cancer. It was the first time I'd heard of anything like that. That lecture influenced the whole direction of my career: I knew that developing this kind of precision approach to diagnosing cancer was exactly what I wanted to do.”

Another life-changing event occurred around that time. Dr. Pritchard met his wife-to-be, Heather Cheng. She was also a student in the Medical Scientist Training Program, and also interested in treating cancer patients. Today, her area of focus is on the disease that has played such a prominent role in Dr. Pritchard’s family history—prostate cancer.

Today, Heather Cheng, MD, PhD is a medical oncologist at SCCA, known for her great rapport with patients. “At home,” says Dr. Pritchard, “we have this back and forth where I'm on the lab side and she's on the clinical side with patients. We complement each other really well.”

Tinkering in the garage

After completing the PhD part of his program in 2005, Dr. Pritchard felt drawn to the importance of connecting research with the needs of both doctors and patients in the clinic. In graduate school, he built complicated diagnostic tools—quantitative profiles of multiple RNA expression levels—along the lines suggested by Dr. Friend’s lecture. But he noticed that much of this highly sophisticated tinkering wasn’t immediately useful. “I recognized,” says Dr. Pritchard, “a lack of true ‘translators’—people who can bring new technologies from the research realm into the clinic.”

Fortunately, there’s a discipline called Laboratory Medicine, which develops the skill set needed to make these translations. University of Washington has one of the strongest residency programs in Laboratory Medicine in the country, and that was how Dr. Pritchard opted to complete his residency and fellowship training.

Precision Medicine comes of age

In 2011, Dr. Pritchard joined the faculty at UW Medicine, making him part of the SCCA family. From this point to the launch of UW-OncoPlex was less than two years—an astonishingly short period of time for the development of such an important breakthrough. The truth is, key forces and trends were culminating at this particular time. These include:

Medically, doctors were learning that certain solid tumors such as lung cancer, colon cancer, and melanoma were caused by specific mutations that made them susceptible to treatment with newly approved targeted drugs.

Technologically, next-generation DNA sequencing was becoming available, making it much easier and more affordable to identify mutations that cause cancer.

Institutionally, SCCA recognized the importance of Precision Medicine and supported the development of new diagnostic tools.

Collegially, the faculty at UW Medicine includes Mary-Claire King, professor of Genome Sciences and Medicine, who discovered important genetic markers for breast cancer, thus proving that cancer is an inherited disease. Dr. King and her close colleague, Dr. Tom Walsh, shared their expertise in next-generation sequencing and building diagnostics that identify inherited mutations. Dr. Walsh partnered closely with Dr. Pritchard to develop the UW-OncoPlex assay. The test uses parallel technology to the BROCA assay, a pioneering achievement developed by Dr. Walsh and Dr. King, which they have used to test for inherited mutations in over 2,000 cancer patients and their family members.

Clinically, oncologists at SCCA, including Dr. Renato Martins and Dr. Keith Eaton worked closely with Dr. Pritchard, helping to define which genes UW-OncoPlex would profile and how the interpretative report should be presented.

At its debut in August 2012, UW-OncoPlex was capable of identifying 194 mutations—each with an available therapy with proven beneficial results for patients. However, Dr. Pritchard says it is still “early days” for the test. The UW-OncoPlex panel will keep expanding as new mutations are discovered and new therapies are developed.

After Hours

Outside of work, they enjoy their family life. Dr. Pritchard enjoys playing bridge. Dr. Cheng’s a big reader. Together they enjoy the performing arts, going for day hikes, and taking weekend trips to places like Eastern Washington or Palm Springs in search of sunshine during the depths of the Seattle winter.

However, helping patients is never too far off their radar. As Dr. Pritchard describes it, “Most weekends we go out to breakfast. Part of our routine is to work through the New England Journal of Medicine’s ‘Case of the Week.’ Heather and I take turns reading the clinical case history to each other and then think through the diagnosis…” Clearly, this is a couple that shares a passion for their profession.