Imagine this: Two children diagnosed with leukemia share the identical genetic mutation, yet one battles a relentless, treatment-resistant disease while the other responds well to standard care. It's heartbreaking, and it raises a crucial question – what makes the difference? A groundbreaking study from Mount Sinai suggests the answer lies in timing, potentially revolutionizing how we approach childhood leukemia. But here's where it gets controversial – could this discovery lead to broader debates about prenatal screening and medical ethics? Stick around, because this insight might just change how we view cancer in kids.
Press Release
Groundbreaking Mount Sinai Research Reveals How the Timing of Genetic Mutations in Leukemia Influences Disease Severity, Paving the Way for Targeted Treatments
New York, NY
(December 08, 2025)
Scientists at the Icahn School of Medicine at Mount Sinai have made a fascinating discovery: kids with the same leukemia-triggering gene alteration can experience vastly different results based on when that mutation happens during their development. For beginners, leukemia is a type of blood cancer where abnormal cells multiply uncontrollably, and it's one of the most common cancers in children. This new research highlights a crucial factor often overlooked in cancer studies.
Led by Elvin Wagenblast, PhD, an Assistant Professor in Oncological Sciences and Pediatrics at the Icahn School of Medicine at Mount Sinai, the team published their findings in Cancer Discovery, a prestigious journal from the American Association for Cancer Research. Their work demonstrates that leukemia starting before birth tends to be more ferocious, spreading quickly and resisting treatments more fiercely. This insight adds an essential layer to personalized medicine for pediatric leukemia, helping doctors tailor approaches beyond just looking at genes.
Dr. Wagenblast and his colleagues in the Wagenblast Lab tackled a fundamental puzzle: how a healthy blood stem cell – the building blocks of our blood system – turns into a cancerous one. They used advanced CRISPR/Cas9 technology, a gene-editing tool that acts like molecular scissors to cut and modify DNA precisely, on real human blood stem cells. This allowed them to mimic various stages of acute myeloid leukemia (AML), a particularly aggressive blood cancer. To make this clearer, think of CRISPR as a smart editor that can rewrite specific parts of our genetic code, helping researchers simulate diseases without harming patients.
The researchers introduced a specific cancer-causing protein called the NUP98::NSD1 fusion – formed when two genes mistakenly join together – into blood stem cells at different life stages, from before birth through infancy, adolescence, and into adulthood. This created the first human-based model to observe how the exact same genetic change behaves differently depending on timing, offering a realistic window into leukemia's development.
The outcomes were eye-opening: stem cells from prenatal stages easily morphed into aggressive leukemia, forming a more basic and primitive type of the disease. In contrast, those from later stages resisted transformation and needed extra mutations to turn cancerous. Prenatal leukemia stem cells, which are faulty blood stem cells that emerge before birth and can spark certain childhood leukemias, stayed mostly inactive (or quiescent) and depended on unique energy sources tied to their cancerous state – features absent in later-onset cases. And this is the part most people miss: even though these prenatal cells seem dormant, their quiet nature makes them tough to eradicate with usual therapies, explaining why these leukemias act so fiercely despite matching genetics.
By examining gene activity in individual cells from their models, the team spotted a 'prenatal signature' – a pattern of gene expression that can predict if a child's leukemia originated before birth. In real patients, this signature linked strongly to poorer outcomes, like harder-to-treat disease and higher relapse risks. For those new to this, gene expression is basically how genes are turned on or off, influencing cell behavior, and this signature acts like a fingerprint for identifying high-risk cases.
'This research shows that age matters right down to the cell level,' explains Dr. Wagenblast. 'The identical mutation acts so differently based on when it occurs. Grasping this opens up fresh strategies to spot at-risk patients and customize treatments that go further than traditional genetic checks.'
The group also explored treatments on the toughest leukemia stem cells and found them particularly sensitive to venetoclax, an FDA-approved medication already in use. Combining venetoclax with standard chemotherapy greatly lessened the disease's intensity in their lab models. As an example, venetoclax works by blocking a protein that helps cancer cells survive, and pairing it with chemo is like a double-team attack that could save lives.
'These results provide solid evidence for doctors to try venetoclax mixes in NUP98-rearranged AML, especially for young patients where the illness likely started prenatally,' notes Dr. Wagenblast.
Knowing the leukemia's start time could empower physicians to select better therapies sooner, cutting down on guesswork, preventing drug resistance, and lowering relapse chances. Conceptually, this study flips our understanding of pediatric cancer – the moment the first mutation appears isn't just a detail; it shapes everything from how the disease grows to how it fights back against treatment.
The research unlocks possibilities for new diagnostics to detect prenatal leukemias, venetoclax-centered combo treatments that hit vulnerable cancer stem cells spot-on, and trials that factor in developmental timing for better risk evaluations. And here's where it gets controversial – as we develop these tools, should we consider widespread testing during pregnancy to catch potential cancer risks early? It raises ethical questions about over-screening and the stress it might cause families, even if it saves lives.
Looking ahead, the team aims to create treatments that directly attack the energy pathways unique to prenatal leukemias, aiming to wipe out cancer stem cells selectively while leaving healthy ones untouched. This could be a game-changer, similar to how targeted therapies in other cancers have improved survival rates without broad side effects.
The study partnered with experts from the Fred Hutchinson Cancer Center, Children's Hospital of Philadelphia, and Cincinnati Children’s Hospital, supported by grants from the National Institutes of Health and private funders.
About the Icahn School of Medicine at Mount Sinai
The Icahn School of Medicine at Mount Sinai stands out globally for its top-tier research, education, and patient care. As the sole academic affiliate for the seven hospitals in the Mount Sinai Health System – one of the nation's biggest academic health networks – it serves New York City's diverse population with cutting-edge medicine.
The school offers competitive MD, PhD, MD-PhD, and master's programs, enrolling over 1,200 students. It runs the country's largest graduate medical education initiative, training more than 2,700 residents and fellows across the system. Its Graduate School of Biomedical Sciences provides 13 advanced degrees, drives cutting-edge basic and applied research, and mentors over 560 postdoctoral fellows.
Ranking 11th nationally in NIH funding, it's in the top 1% for research dollars per researcher per the Association of American Medical Colleges. Over 4,500 experts in science, teaching, and medicine collaborate across numerous departments and institutes, focusing on turning research into real treatments. Through Mount Sinai Innovation Partners (MSIP), the system turns medical breakthroughs into practical, commercial solutions.
- Mount Sinai Health System member hospitals: The Mount Sinai Hospital; Mount Sinai Brooklyn; Mount Sinai Morningside; Mount Sinai Queens; Mount Sinai South Nassau; Mount Sinai West; and New York Eye and Ear Infirmary of Mount Sinai.
About the Mount Sinai Health System
Mount Sinai Health System ranks among the largest academic medical networks in the New York area, with 48,000 staff across seven hospitals, over 400 outpatient clinics, more than 600 labs for research and care, a nursing school, and a leading medical and graduate school. It tackles complex health issues by advancing science, creating safer therapies, training future leaders, and offering high-quality care to local communities.
By blending hospitals, labs, and schools, Mount Sinai delivers holistic care from infancy to old age, using innovations like AI and data tools while prioritizing patients' physical and emotional well-being. The system includes around 9,000 primary and specialty doctors and 10 joint-venture centers in New York's five boroughs, Westchester, Long Island, and Florida. Its hospitals frequently top lists like Newsweek’s “World’s Best Smart Hospitals” and U.S. News & World Report’s “Best Hospitals” and “Best Children’s Hospitals.” The Mount Sinai Hospital earned spots on the U.S. News & World Report “Best Hospitals” Honor Roll for 2025-2026.
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But here's the controversial twist: As we embrace timing-based medicine, are we ready to redefine 'prevention' for cancers like leukemia, potentially screening embryos or fetuses? And this is the part most people miss – how might this shift resources away from other childhood illnesses? What are your thoughts? Do you see this as a leap forward or a Pandora's box of ethical dilemmas? Share your views in the comments – agree, disagree, or add your own take!
