Mendelspod Podcast

Molecular residual disease, or MRD, has been part of oncology’s vocabulary for decades. But knowing something is there and being able to measure it precisely are two very different things. In today’s show, we explore how MRD testing moved from a long-standing clinical suspicion to one of the most consequential tools in modern oncology.
Joining us on the program are Chris Hourigan, Director of the Fralin Biomedical Research Institute Cancer Research Center (DC) at Virginia Tech, bringing the academic and clinical AML lens, and Gary Pestano, Chief Scientific Officer at Biodesix, offering the industry and diagnostic development perspective.
Hourigan reminds us that MRD itself isn’t new. What was missing were the tools. From counting cells under a microscope to flow cytometry and now highly sensitive molecular techniques including droplet digital PCR, MRD has evolved into a quantitative, actionable signal.
Coming from the side of commercializing and scaling assays, Pestano underscores the central challenge of distinguishing meaningful signal from background noise. “There is a lot circulating in our blood. The key is what is meaningful, what is not meaningful,” he explains. Sensitivity alone isn’t enough. Target selection, bioinformatic filtering, validation at scale, and real-world reproducibility all determine whether MRD can truly guide care.
The field is very much still work in progress, say both.
Looking ahead, they point toward quantification as the next frontier. MRD is no longer just about detecting what remains. It’s about deciding what happens next.
“We’ve been talking about MRD as if it’s a binary concept” says Hourigan. “I can imagine in the future, there’s going to be windows, and we will tune therapy to what comes next.”
Thank you to Bio-Rad for sponsoring today’s show. Bio-Rad is your trusted partner for absolute quantification and reproducible results in oncology research. Bio-Rad helps you move from data to confident decisions. Learn more at bio-rad.com/oncology.


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For two decades, tests like Oncotype DX have helped oncologists decide which early-stage breast cancer patients should receive chemotherapy. But those tools were designed mainly to predict early recurrence, leaving physicians with far less clarity about the risk that cancer might return years later.
For today’s program, George Sledge, Chief Medical Officer at Caris Life Sciences, discusses new findings from the TAILORx trial showing how multimodal AI—combining molecular sequencing, digital pathology, and clinical data—can improve long-term prediction of breast cancer recurrence.
Sledge explains that breast cancer recurrence may actually reflect two different biological processes unfolding over time. Molecular signals captured through RNA analysis appear most informative for predicting recurrence in the first five years, while computational analysis of digital pathology images becomes especially powerful for predicting recurrence later in the disease course.
“The best results come from looking at multiple omic levels,” Sledge says, describing a shift away from single biomarker tests toward integrated biological analysis.

We began this podcast back around the time the ENCODE project announced that much of the genome was biochemically active. The big science project was undoing the tidy idea of “junk DNA,” and not without controversy. But activity is not the same as purpose. On today’s show, we move past the question of whether the non-coding genome does something and ask a more ambitious one: why has evolution retained so much genomic material unless it carries adaptive potential?
Theral speaks with Sudhakaran Prabakaran, computational biologist at Northeastern University and founder of NonExomics, about his provocative new book, “Eclipsed Horizons: Unveiling the Dark Genome.” Drawing on his lab’s work cataloging more than 250,000 non-canonical proteins, Prabakaran argues that regions outside traditional gene definitions are constantly generating novel open reading frames—previously unrecognized proteins that may shape adaptation, speciation, and disease.
Chapters:
(00:00) Identical Genomes, Wildly Different Fish
(04:00) The Dark Proteome Wakes Up
(10:00) Protein Pop-Up Shops
(20:00) Homo Minimus and the Space Thought Experiment
(30:00) Precision Medicine Beyond the Exome
From rapidly diversifying cichlid fishes to human accelerated regions (HARs) of the human genome linked to schizophrenia, he makes the case that protein birth and death is continuous, cheap, and exploratory. In his framing, the “dark genome” functions less like debris and more like a flexible evolutionary sandbox—capable of producing latent biological parts that can be deployed under stress or even extreme environments like spaceflight.
The book goes beyond ENCODE’s demonstration of activity and asks what that activity is for, crossing into that taboo in biology, teleonomic analysis. Weaving together proteomics, evolutionary biology, information theory, and even speculative extensions into space biology, Prabakaran suggests that genomes may be structured not just to preserve past adaptations, but to enable future ones.
For those of you staying put on the ground, the implications are very tangible for precision medicine. His company NonExomics is using non-canonical protein signatures to stratify cancer patients and refine difficult diagnoses, arguing that the next wave of biomarkers may lie outside the exome.
Provocative? Certainly. Grounded in emerging proteomics tools and real clinical cases? Also yes. This conversation probes directly into that mysterious future of biology.


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“We have been talking now for 15, 20 years about the diagnostic odyssey. That shouldn’t exist anymore. The new odyssey is the therapeutic odyssey.”
That’s Stephen Kingsmore, president and CEO of Rady Children’s Hospital (he just announced his retirement), explaining the impact of a new genome mapping technology from Illumina.
Whole-genome sequencing has transformed diagnosis, but some of the hardest pediatric cases persist because the structure of the genome has remained difficult to resolve. Today on Mendelspod, we cover Illumina’s newly launched proximity mapped reads, showing how long-range genomic context can be captured directly on existing Illumina sequencers and integrated into the lab workflow. The conversation traces how this added structural clarity is already improving diagnostic confidence and, critically, enabling highly precise n-of-1 therapies such as antisense oligonucleotides (ASOs).
Olivia Kim-MacManus, a pediatric neurologist and ASO trial leader, shows how the new diagnostic precision directly feeds therapeutic design.
“All of these genetic therapy approaches hinge on precise diagnostics,” she notes, emphasizing that allele-specific and haplotype-aware targeting is essential for ASOs and other emerging gene-based interventions.
From the product and workflow side, Ali Crawford joins us as Senior Director of Science Research at Illumina, detailing how the technology works without requiring new instruments or complex workflows, eliminating the need for separate library preparation steps.
“You just order the kit and go,” she says, highlighting how preserving spatial information on the flow cell unlocks variant calls and structural insight that were previously inaccessible with their standard short-read sequencing.
When genome structure comes into better focus, treatments are no longer theoretical.


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CareDx is a company on the move. For years, they have been a bellwether in molecular diagnostics. Their early bet on gene expression testing in transplant medicine, their bruising fight over Medicare coverage, and their pivot into cell-free DNA monitoring have all reflected the growing pains of precision medicine itself.
Now, under CEO John Hanna, the company looks less like a single-test diagnostics firm and more like a clinical ecosystem.
Hanna brings an unusual vantage point. He began his career in health insurance before moving into molecular diagnostics—giving him insight into both innovation and reimbursement. That dual perspective shaped CareDx’s recent evolution: focus tightly on a defined clinical niche—transplantation—while expanding horizontally into the tools, software, and services that surround it.
Today, CareDx operates across three segments: lab products (including high-resolution HLA typing kits using PCR, NGS, and nanopore), a growing software and patient solutions business, and its flagship genomics portfolio led by AlloSure, its donor-derived cell-free DNA assay. What distinguishes the company now is its “solution selling” approach—engaging transplant centers not just with a test, but with workflow software, quality reporting tools, specialty pharmacy, and EMR integration.
“Our solution selling strategy is working,” he says today.
At the scientific core remains the effort to replace invasive biopsies with molecular monitoring. AlloSure’s innovation—detecting donor-derived cell-free DNA without requiring donor genotyping—made routine blood-based rejection monitoring scalable. Yet adoption is not purely technical.
“The biggest challenge with our space is building belief that molecular testing can replace tissue biopsy.”
Clinician education, clinical trials, and guideline inclusion remain central to shifting standards of care. CareDx has leaned heavily into this, hiring medical leadership specifically to translate data into practice. The company is also layering AI on top of its molecular assays. AlloSure Plus integrates genomic results with EMR-derived clinical variables to generate a rejection risk score. CareDx’s operational mantra has been to put the burden of complexity on the company, not the clinician.