New study boasts 90% accuracy when using PARR to diagnose canine lymphoma


Article originally published in NEWStat, an American Animal Hospital Association Publication 

Written by Tony McReynolds

Who measures the measurements? Who diagnoses the diagnostics? In short, who assays the assays?

Veterinarians have been using polymerase chain reaction for antigen receptor rearrangement (PARR), a readily available molecular assay that helps diagnose some kinds of canine lymphoma, for years. But no one really knew how accurate those assays were—because none have undergone a truly rigorous benchmarking study to determine the accuracy of PARR assays in general, regardless of the manufacturer.

Until now.

In a study published in the Journal of Veterinary Internal Medicine, Ethos Veterinary Health, Ethos Discovery, and the Translational Genomics Research Institute (TGen) found that their version of the test, called ePARR, was more than 90% accurate among a range of lymphoma sample types.

The results of the ePARR test study are based on an analysis of 180 dogs with cancer. The researchers used ePARR to confirm whether the dogs in the study had lymphoma and then to determine what type they had.

“We’re very excited about it,” Chand Khanna, DVM, PhD, DACVIM (Oncology), DACVP (Honorary), told NEWStat. Khanna is chief science officer of Ethos Veterinary Health, president of Ethos Discovery (a 501(c)3 independent not-for-profit incubator of scientific innovation), and co-senior author of the study.

Khanna emphasized that ePARR is not a new kind of assay but rather a new brand of assay, and the way it works to diagnose lymphoma isn’t different from what’s currently out there. He said the big takeaway here is the accuracy of the new study, which he calls “very rigorous.” He pointed out that the sheer number of dogs tested “well exceeds what has been done” in previous studies.

“What’s new is that doctors can offer [PARR assays] with a greater confidence in the performance of the assay than was possible before,” Khanna said.

Most dogs with lymphoma can be easily diagnosed using a simple microscopic evaluation of cells taken from the lymph node, so PAAR isn’t a first-line diagnostic test. However, a small minority of dogs yield tissue samples that display unusual features under the microscope, which makes some clinicians hesitant to begin treatment for lymphoma. In those cases, Khanna said, “you need a much more rigorous confirmatory test.”

PAAR, for example.

NEWStat asked Barbara Biller, DVM, DACVIM, retired associate professor of oncology at the Flint Animal Cancer Center at Colorado State University and practicing veterinarian at Boulder Road Veterinary Specialists in Lafayette, Colorado, what the study meant for veterinarians dealing with suspected cases of canine lymphoma.

“It’s further validation of [PARR],” Biller said. “We don’t need it to diagnose most cases of lymphoma but when we do need it, it can be really helpful. [The study clears up] some of the questions we have as far as how accurate it is for different samples.”

“This is the kind of data we need in this profession,” Biller added. “You have an organized, systematic evaluation of a technique. And it’s really good to see that kind of research.”


Read the article on NEWStat

TGEN-Ethos Study Underscores Need for Setting High Standards in Veterinary Cancer Diagnostics

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Written by Steve Yozwiak

PHOENIX, Ariz. — May 21, 2019 — Ethos Veterinary Health, Ethos Discovery, and the Translational Genomics Research Institute (TGen), an affiliate of City of Hope, announced today that they have developed a highly accurate test for the diagnosis of canine lymphoma.

In a study published in the Journal of Veterinary Internal Medicine (JVIM), Ethos and TGen found that their test, called ePARR, was more than 90 percent accurate among a range of lymphoma sample types (link to the complete JVIM article is below).

TGen conducted genetic analysis of more than 180 dogs with naturally occurring cancer to confirm if they had lymphoma, and then determine exactly what type of lymphoma, which is a common and aggressive cancer in dogs.

“An ongoing need exists for robust validation of molecular diagnostics in veterinary medicine. This study is an example of exhaustive validation of one such molecular test,” said Dr. Will Hendricks, an Assistant Professor in TGen’s Integrated Cancer Genomics Division, and one of the study’s co-senior authors. “Overall, ePARR is more than 90 percent accurate across sample types and diagnostic settings.”

The study authors suggest that such tests could be even more accurate if testing facilities adopted more uniform testing techniques, established uniform high performance standards, and made their results more readily available to the general research community.

“In the veterinary diagnostic area, there is a need for methodological consistency and transparency. Each lab has their own methods for how to run the same test,” said Dr. Chand Khanna, Chief Science Officer of Ethos Veterinary Health, and also a co-senior author of the study. “Our validation of ePARR included over 180 dogs and a broad diversity of sample types, including cell pellets, air dried aspirates, and formalin-fixed paraffin-embedded tissues.”

Shukmei Wong, who is a TGen Senior Research Associate in the Hendricks Laboratory, who conducted the study experiments, and is a co-author of the study, said: “I hope this paper will inspire more reporting of assay methods and metrics, and help drive the creation of reference standards and more consistent protocols in diagnostics in veterinary medicine.”

Dr. Sam Stewart, Science Commercialization Fellow at Ethos Veterinary Health, agrees:

“It is truly unique to see such complete rigorous validation of a molecular assay in this field, and we hope this standard of transparency and quality will be followed by others. As a Critical Care doctor, I am proud to offer this high level of quality in a diagnostic assay to my patients.”

Molecular level investigations into dog DNA could someday not only improve the health of dogs with cancer, but also help contribute to a better understanding of cancer in humans, as well.

This study was funded by non-profit Ethos Discovery, which is evaluating options to make the ePARR test available to veterinarians and pet owners.

The study — Polymerase Chain Reaction for Antigen Receptor Rearrangement (PARR): Benchmarking performance of a lymphoid clonality assay in diverse canine sample types — was published April 2 in the Journal of Veterinary Internal Medicine.

No dogs were harmed during this research. Only tissue samples from pet dogs with naturally occurring cancers were examined.


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About Ethos Veterinary Health

Ethos is a veterinary health company with hospitals across the U.S. providing advanced medical care for pets. Our approach includes a focus on transformative science, continuous learning, growth for team members, and the development of collaborative relationships. For more information, visit

About Ethos Discovery

Ethos Discovery is a 501(c)(3) non-profit incubator of scientific innovation that seeks to improve health outcomes in pets and humans with complex medical problems, including cancer. For more information, please visit

About TGen, an affiliate of City of Hope

Translational Genomics Research Institute (TGen) is a Phoenix, Arizona-based non-profit organization dedicated to conducting groundbreaking research with life-changing results. TGen is affiliated with City of Hope, a world-renowned independent research and treatment center for cancer, diabetes and other life-threatening diseases: This precision medicine affiliation enables both institutes to complement each other in research and patient care, with City of Hope providing a significant clinical setting to advance scientific discoveries made by TGen. TGen is focused on helping patients with neurological disorders, cancer, diabetes and infectious diseases through cutting-edge translational research (the process of rapidly moving research toward patient benefit). TGen physicians and scientists work to unravel the genetic components of both common and complex rare diseases in adults and children. Working with collaborators in the scientific and medical communities worldwide, TGen makes a substantial contribution to help our patients through efficiency and effectiveness of the translational process.

For more information, visit: Follow TGen on Facebook, LinkedIn and Twitter @TGen

Media Contact at TGen:
Steve Yozwiak
TGen Senior Science Writer