Consider fighting cancer without removing immune cells from the body, modifying them in a laboratory, and returning them. Instead, a simple injection could give those cells the instructions they need to recognise and attack cancer cells. Scientists at MIT (Massachusetts Institute of Technology) have now showcased that this new cancer immunotherapy approach can work in mice.
In a novel study, MIT scientists delivered genetic material using nanoparticles directly into immune cells, which converted them into cancer-fighting cells within the body. The therapy has successfully restored damaged liver tissues and eliminated some tumours in mice. The findings were published in Nature Biotechnology and announced by MIT on 13 October 2026. All of the results come from experiments in mice, and the researchers say further work is needed to establish whether the method is safe and effective in people.
Note: This article is for information only and is not medical advice. The work described is preclinical: it has been tested in mice, not in humans, and no CAR NK cell therapy has been approved by the FDA.
Why Does Cancer Immunotherapy Need a New Approach?
One of the prime developments in cancer treatment has been that of CAR-T cell therapy. It involves harvesting the patient’s T cells, modifying them in the laboratory, and then reinjecting them into the body to fight cancer cells.
Over the past decade, the US Food and Drug Administration (FDA) has approved seven CAR T-cell cancer treatments, according to MIT. They have been especially effective against certain blood cancers that arise from B cells, including some leukaemias, lymphomas and multiple myeloma.
However, preparing these modified cells requires specialised facilities, trained staff, and several laboratory procedures. This makes treatment expensive and difficult to produce.
MIT researchers wanted to see whether they could skip these steps by modifying immune cells directly in the body.
How Did MIT Researchers Make This Cancer Immunotherapy Discovery Possible?
The scientists focused on NK (natural killer) cells, a type of immune cell that can recognise and destroy abnormal cells.
NK cells have a practical advantage when the disease target is a T cell. If CAR T cells are engineered to attack diseased T cells, the modified cells may recognise and destroy one another, because they carry the same surface protein as their target. NK cells are a different cell type, so this problem does not arise.
To reprogram or manipulate NK cells, the researchers developed lipid nanoparticles (LNPs), which are small fat-based particles.
LNPs contain the molecule of mRNA (messenger RNA). Their surfaces are coated with antibody fragments to enable binding to NK cells.
As soon as the mRNA enters the NK cell, it instructs the cell to produce a protein known as a CAR (chimeric antigen receptor).
This receptor helps the immune cell recognise specific targets, such as CD3 on T cells or CD19 on B cells. The modified NK cell can then attack cells carrying the targeted protein.
The important difference is that scientists can create these CAR-NK cells without removing them from the body.
This could make cancer immunotherapy easier to produce by reducing the need for complex cell-engineering procedures outside the body.
Read also: Moderna and CARsgen partner on CAR-T cell therapy and cancer vaccine combo
The senior author is MIT professor Daniel Anderson, of the Koch Institute and IMES. The lead authors are postdoctoral researcher Yuang Chen and graduate students Julia Monkovic and Haseeb Mughal, and MIT professor Robert Langer is also an author. The work was funded by Sanofi, the Marble Centre for Cancer Nanomedicine and a Koch Institute core grant from the National Cancer Institute.
Findings in Animal Models
The researchers first tested whether the nanoparticles could successfully deliver their instructions to NK cells in mice.
The study reports that about 80% of the targeted NK cells in the mice were successfully reprogrammed.
The team then tested the approach against an aggressive form of melanoma. According to the study, three of the five treated mice reached complete remission, meaning their tumours were no longer detectable.
Another Cancer Immunotherapy experiment focused on T-cell lymphoma. For this test, scientists used humanised mice that had received human blood cells, temporarily giving them some features of a human immune system.
After five nanoparticle injections, the tumours in these mice were eliminated. The study reports that the results were comparable to those obtained with CAR NK cells engineered outside the body and then infused.
The researchers also investigated autoimmune hepatitis, a disease in which the immune system mistakenly attacks healthy liver cells.
In mice with this condition, a single injection removed the harmful T cells and allowed the damaged liver tissue to heal.
Implications and Limitations
The results suggest that the same technology could be useful for treating both cancer and diseases caused by abnormal immune responses.
The MIT team plans to test whether the method can be extended to autoimmune conditions driven by dysfunctional T cells, such as multiple sclerosis and rheumatoid arthritis.
Currently, it is an experimental approach. All results reported are based on experiments conducted in mice. Researchers have to demonstrate the technology’s effectiveness and safety in human trials. There is no FDA-approved CAR-NK cell therapy available yet.
Should the approach prove safe and effective in humans, it could, in principle, allow a patient’s own immune cells to be reprogrammed by injection, without laboratory cell manufacturing. This remains hypothetical.
What the mouse study shows is that the nanoparticles could make CAR NK cells in vivo, that is, inside the animal’s own body, and that these cells cleared tumours in the models tested. If the approach holds up in human trials, the researchers suggest it could make advanced immune-cell therapies simpler and cheaper to produce. That remains a research outlook, not a proven patient benefit.
FAQs
What did the MIT study actually show?
In mice, lipid nanoparticles carrying mRNA reprogrammed natural killer (NK) cells in vivo into CAR NK cells, which cleared tumours in the models tested and allowed damaged liver tissue to heal in a model of autoimmune hepatitis.
How is this different from CAR T-cell therapy?
Conventional CAR T-cell therapy takes a patient’s T cells, engineers them in a laboratory and infuses them back. Here, the immune cells are reprogrammed inside the body by injection, which removes the ex vivo manufacturing step.
Why use NK cells instead of T cells?
When the disease target is itself a T cell, engineered CAR T cells can recognise and destroy one another because they carry the same surface protein. NK cells are a different cell type, so this does not happen.
Is this Cancer Immunotherapy treatment available to patients?
No. The work is preclinical and has only been tested in mice. No CAR NK cell therapy is approved by the FDA, and human trials would be needed first.
