August 12, 2021

Research Spotlight: Alessandro Leal, and Jillian Phallen.

Mark Foundation Momentum Fellows Team Up to Develop Blood Test for Cancer Detection


Cancer biologist, Jillian Phallen, PhD, and Alessandro Leal, MD.

By detecting trace amounts of tumor DNA from the blood, physician scientist, Alessandro Leal, MD and cancer biologist, Jillian Phallen, PhD hope to develop a blood test for cancer detection that is minimally invasive, cost-effective, and able to detect tumors before even the faintest of symptoms arise.

Growing tumors in the body are constantly turning over, casting off dead cells and spilling their contents, including small fragments of DNA, into the bloodstream. Scientists are increasingly interested in harnessing this DNA to develop diagnostic tests for cancer that are as easy as a standard blood draw. However, the challenge they are facing is that tumor DNA is only a fraction of the total extracellular DNA in the blood. So, separating the tumor DNA from that of healthy cells remains a challenge.

In 2018, Leal and Phallen, both conducting research in the lab of Victor Velculescu at Johns Hopkins University, received a Momentum Fellowship from the Mark Foundation in order to further their methods of detecting tumor DNA in the blood. Using a combination of artificial intelligence and next generation sequencing, they developed a novel approach that uses whole genome sequencing to identify tumor DNA through differences in DNA fragment size and morphology. The technique is unique in that it focuses on physical characteristics of the tumor DNA rather than specific cancer mutations. In 2019, they published a paper in Nature showing the test worked to identify seven different types of cancer. 

Later that year, Leal, Phallen, and their partners at Johns Hopkins launched a company, called DelfiDiagnostics, to continue developing these tests, working to optimize sensitivity and specificity across various types of cancer. The company has recently started recruiting patients into clinical trials and hopes to have results next year. Phallen and Leal are most excited about bringing these tests into the clinic to aid in early detection.

”There are a lot of amazing ways to combat cancer, but I am most excited about moving detection from late to early stages where the disease is much more manageable and oftentimes curable,” said Phallen.

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