May 7, 2021 • 4 Min

Studying a New Approach for the Liquid Biopsy

Allyson Ocean, M.D. and Ying-Hsiu Su, Ph.D.

The so-called “liquid biopsy,” the use of bodily fluids instead of tissue to detect cancer, is the subject of much research in the field of oncology.

That’s due in no small part to the process being more patient-friendly than a traditional biopsy that uses tissue samples from a tumor. One of the major research efforts showing promise in pancreatic cancer is using this liquid biopsy approach to aid earlier diagnosis. The idea is to provide more patients a pathway to surgical intervention which, at this time, is the only potentially curative treatment. Studies are also ongoing to see if liquid biopsies can help in identifying prognostic biomarkers and disease management.

But blood is not the only liquid researchers are studying. Urine may provide some of the same information as blood—possibly even more. A pilot study at Weill Cornell Medicine in New York is researching whether pancreatic cancer can be detected earlier by using a urine test for mutated KRAS DNA. Mutated KRAS is present in about 95 percent of pancreatic cancers and is a driver of pancreatic cancer growth.

This clinical trial is for men and women diagnosed with metastatic pancreatic cancer. The study will also recruit a control group of healthy individuals. Eligible patients will have urine and blood collected for correlative reference.

The process of collecting urine is just as simple as you may think: Patients just void into a cup, explains gastrointestinal oncologist and principal investigator Allyson Ocean, M.D., Associate Professor of Medicine at Weill Cornell Medical College of Cornell University (New York). “Very simply, KRAS proteins should not be found in a patient’s urine. Urine is a filtrate of blood and if KRAS is found in the urine, that tells us something is going on with that individual,” she says, adding that positive results will be confirmed with imaging or with a known pathology report.

The goal, Ocean explains, is to one day have a noninvasive test to detect a KRAS-mutated cancer like pancreatic cancer or another one like colorectal cancer. Validating a potential screening test like this is a long process, since thousands of samples are needed over time. This pilot study is the first step to see if the mutated KRAS DNA can be picked up in the urine sample for pancreatic cancer detection.

“Although the process of collecting urine is very easy, the technology behind this approach is very sophisticated,” says Ocean. “Pancreatic cancer is a disease that desperately needs earlier detection. We need to explore all avenues and this approach is very interesting.”

An Easier Test

The study is sponsored by JBS Science (Doylestown, Pennsylvania). The company’s focus is translating its circulating cell-free DNA (cfDNA) in urine technology into improved cancer screening and management, to reduce cancer morbidity.  “At first, people didn’t believe it was feasible to find tumor DNA in urine,” explains Ying-Hsiu Su, Ph.D., of JBS Science and Professor of Translational Medical Science at the Baruch S. Blumberg Institute (Doylestown). “Everyone thought it was just urine and who cares, but once we showed that it can be done, people started to take notice,” says Su, who is also an Associate Member of the Early Detection Research Network of the National Cancer Institute.

Su is a leader in the field of transrenal DNA for cancer detection. She and a multi-institution team showed that human urine was a source of circulating DNA for molecular diagnosis and prognosis. Now, among other efforts, she is working with colleagues at JBS to commercialize its first liquid biopsy product to screen for the early detection of hepatocellular carcinoma.

“There have been significant advances in technology that allow for the study of cancer genetics using liquid blood biopsies, and these advances led to biopsy tests already being used for cancer management,” she explains. “But there have also been other advances in research, particularly in molecular biomarker research, along with our findings that tumor-derived DNA in the circulation can be detected in urine. It’s those efforts that are now providing a very important opportunity to use urine to detect cancer-related molecular markers present in the circulation.”

Although blood is the most direct fluid for detection of ctDNA, and currently has the most ongoing research, “urine is unique,” says Su.  “It really is the most noninvasive approach. There is absolutely no discomfort for a patient. It can be collected at home, and it ships and stores easily.” It also contains fewer contaminating proteins.

“This (pancreatic cancer) study is very early stage,” she adds. “But ultimately, what we hope for in pancreatic cancer, colon cancer, liver, and others is to find a way to more easily monitor those at higher risk of disease and really to find a way to detect cancer when it can be more easily treated, giving patients a chance at a better life.”