The cells are ready to use immediately—no waiting, no customization
At McGill University, researchers have found a way to awaken the immune system's own sentinels — natural killer cells — against some of cancer's most resistant forms, not by rewriting their genetic identity, but by temporarily lifting the molecular brakes that hold them back. The approach, tested against leukemia, glioblastoma, and triple-negative breast cancer in preclinical studies, offers something rare in modern medicine: a powerful intervention that can also be undone. In a field where permanence has long been the price of potency, this discovery asks whether control and efficacy might finally coexist.
- Two proteins — PTPN1 and PTPN2 — have been quietly suppressing the immune system's natural killer cells, and blocking them unlocks a dramatically more aggressive anti-tumor response.
- Unlike gene-editing therapies that permanently alter immune cells and cannot be reversed if complications arise, this method uses small-molecule drugs that leave the cells themselves structurally unchanged.
- The treatment sidesteps the costly, weeks-long process of extracting and customizing cells from individual patients by using banked cord blood NK cells that are ready to deploy immediately across multiple patients.
- Clinical trials targeting acute myeloid leukemia — a blood cancer with few options for many patients — are being prepared, though they remain contingent on funding and regulatory clearance.
- If trials proceed, the therapy could offer faster, safer, and more affordable immunotherapy to patients who have already exhausted conventional treatments.
A research team at McGill University has developed a method to significantly enhance the cancer-fighting power of natural killer cells — the immune system's frontline defenders — by temporarily blocking two proteins, PTPN1 and PTPN2, that normally restrain their activity. In preclinical studies, these supercharged NK cells destroyed human cancer cells from leukemia, glioblastoma, kidney cancer, and triple-negative breast cancer, and slowed tumor growth in animal models.
What distinguishes this work is its deliberate departure from genetic engineering. Most cutting-edge immunotherapies permanently alter the DNA of immune cells — effective, but irreversible. The McGill approach uses small-molecule drugs to boost NK cell activity without changing the cells themselves. If side effects emerge, the treatment can simply be stopped and the cells return to their natural state. That reversibility represents a meaningful shift in how much control patients and physicians can retain.
The therapy also addresses a persistent barrier in cell-based cancer treatment: cost and time. Conventional approaches require extracting cells from each patient, culturing them individually, and waiting weeks for a customized product. The McGill team used NK cells derived from donated umbilical cord blood, stored and ready for immediate use — a single batch potentially serving multiple patients without delay or per-patient customization.
Senior researcher Michel Tremblay highlighted the therapy's particular promise for patients who have run out of standard options, with acute myeloid leukemia among the first targets for planned human trials. Research scientist Chu-Han Feng underscored the practical vision: faster, safer, more affordable treatment. The study appeared in EMBO Reports in April 2026, and the team acknowledged the cord blood donors whose contributions made the research possible. Clinical trials await only funding and regulatory approval to begin.
A team at McGill University has found a way to sharpen the immune system's natural killer cells—turning them into more formidable opponents against some of the hardest cancers to treat. The key was simple in concept but powerful in execution: block two proteins that were holding the cells back. In preclinical work, these enhanced NK cells successfully destroyed human cancer cells from leukemia, glioblastoma, kidney cancer, and triple-negative breast cancer. In animal models, the approach also slowed tumor growth significantly.
What makes this discovery stand out is not just that it works, but how it works. Most modern cancer immunotherapies rely on permanently rewriting the genetic code of immune cells—a powerful tool, but one that carries real risk. If something goes wrong, those changes cannot be undone. The McGill researchers took a different path. They used small-molecule drugs to temporarily boost NK cell activity, leaving the cells themselves unchanged. The enhancement is reversible. If side effects emerge, the treatment can be stopped and the cells will return to their baseline state. For patients and doctors alike, that reversibility matters. It means the therapy can be controlled in ways that permanent genetic modification cannot.
The practical advantages extend further. Most cell-based cancer treatments require doctors to extract immune cells from each individual patient, culture them in the lab, and customize them for that person's specific cancer. The process takes weeks, costs thousands of dollars, and demands sophisticated infrastructure. The NK cells used in this study came from donated umbilical cord blood. Scientists at McGill's Cellular Therapy Laboratory isolated, cultured, and stored them so that a single batch could potentially treat multiple patients. The cells are ready to use immediately—no waiting, no per-patient customization, no weeks of delay while a patient's condition may worsen.
Michel Tremblay, the senior researcher and a Distinguished James McGill Professor in the Department of Biochemistry, framed the significance clearly: this approach is especially promising for patients who have exhausted standard options, for whom conventional treatments have failed. Acute myeloid leukemia—an aggressive blood cancer with limited options for many patients—is among the first targets the team hopes to pursue in human trials. Those trials are not yet underway; they are awaiting funding and regulatory approval. But the groundwork is laid.
Chu-Han Feng, a research scientist at the institute, emphasized what this could mean in practice: faster treatment, safer treatment, more affordable treatment. The therapy avoids the complexity of customizing cells for each patient and instead uses drugs that are already known and available to reversibly enhance the NK cells' ability to attack tumors. The study, published in EMBO Reports in April 2026, was supported by multiple Canadian funding bodies and foundations, and the researchers acknowledged the mothers who volunteered to donate the cord blood that made the work possible. What began in a laboratory may soon move into clinics—if funding and approval come through.
Citas Notables
This approach is particularly promising for patients who currently have very few options, when standard treatments have failed.— Michel L. Tremblay, Distinguished James McGill Professor
This approach will make immunotherapy faster, safer and more affordable, avoiding the complex process of customizing cells.— Chu-Han Feng, research scientist at the Rosalind & Morris Goodman Cancer Institute
La Conversación del Hearth Otra perspectiva de la historia
Why does blocking two proteins make such a difference? What were these cells unable to do before?
The proteins—PTPN1 and PTPN2—were essentially brakes on the NK cells' ability to respond to signals that tell them to attack. When you remove the brakes, the cells can mount a much stronger response. They produce more of the chemical signals that drive the immune response and are less susceptible to the tumor's own suppressive tactics.
But if you're blocking proteins, aren't you changing the cell? How is that reversible?
The key is that we're not rewriting the cell's DNA. We're using drugs that temporarily bind to those proteins and disable them. Once the drug wears off or is cleared from the body, the proteins resume their normal function. The cell itself remains genetically unchanged. It's like turning off a light switch rather than removing the bulb.
So you could theoretically give someone this therapy, see how they respond, and stop it if something goes wrong?
Exactly. That's the safety advantage. With genetic engineering, you've permanently altered the cell. If complications arise, you can't undo it. Here, you can. That gives clinicians much more control and flexibility.
Why does it matter that these cells come from cord blood instead of from the patient themselves?
Speed and cost. Extracting and culturing a patient's own cells takes weeks and is expensive. With cord blood cells, you can bank them, prepare them in advance, and have them ready to infuse immediately. One batch can treat multiple patients. It democratizes access—not every hospital needs its own cell manufacturing facility.
What's the next hurdle?
Getting into human trials. The preclinical data is strong, but you need funding and regulatory approval to move forward. They're targeting acute myeloid leukemia first because the need is urgent and the current options are limited. If those trials work, you open the door to treating other aggressive cancers too.