At the core of the innovation is the creation of “CAR-macrophages.” CAR, or chimeric antigen receptor, is a cancer-recognition device already used in some advanced immune therapies
Scientists at the Korea Advanced Institute of Science and Technology (KAIST) have unveiled a breakthrough cancer treatment strategy that could redefine how solid tumours are fought—by turning immune cells already inside tumours into cancer-killing machines. The new approach eliminates the need for complex lab-based immune cell extraction and modification, offering a faster and potentially more scalable form of immunotherapy.
The research team, led by Professor Ji-Ho Park from KAIST’s Department of Bio and Brain Engineering, developed a method in which a drug is injected directly into a tumour. Once inside, the drug is absorbed by macrophages—immune cells that naturally gather in and around tumours. Instead of supporting tumour growth, as they often do, these macrophages are reprogrammed to recognise and destroy cancer cells.
At the core of the innovation is the creation of “CAR-macrophages.” CAR, or chimeric antigen receptor, is a cancer-recognition device already used in some advanced immune therapies. Traditionally, CAR-based treatments require immune cells to be removed from a patient, genetically engineered in a laboratory, and then reinfused—a process that is expensive, time-consuming and difficult to scale.
KAIST’s approach bypasses these hurdles entirely. Using lipid nanoparticles designed to be easily taken up by macrophages, the researchers delivered messenger RNA carrying instructions to produce CAR proteins, along with an immune-activating compound. Once absorbed, the macrophages began producing CAR proteins inside the body itself, effectively transforming into anticancer immune cells on site.
This approach addresses one of the biggest challenges in cancer treatment: solid tumours. Cancers such as gastric, lung and liver cancer form dense, hostile environments that block immune cells from entering or functioning properly. Many existing immunotherapies struggle to penetrate these barriers. Macrophages, however, can infiltrate solid tumours and directly engulf cancer cells, while also activating surrounding immune defences.
In animal studies, the results were striking. When the treatment was injected into tumours, macrophages rapidly absorbed the nanoparticles and became highly effective cancer killers. Tumour growth was significantly slowed in melanoma models, and the immune response appeared to extend beyond the treated tumour, hinting at possible body-wide protection against cancer spread.
Professor Park described the study as “a new concept of immune cell therapy that generates anticancer immune cells directly inside the patient’s body.” He noted that the strategy overcomes two major limitations of existing CAR-macrophage therapies—poor delivery efficiency and the highly immunosuppressive tumour environment.
The study was led by Dr Jun-Hee Han as first author and published on November 18 in ACS Nano, a leading international journal in nanotechnology. While the research is still at the preclinical stage, it opens a promising new direction for cancer immunotherapy.
If successfully translated to humans, this technology could transform solid tumour treatment—by reprogramming the tumour’s own immune environment into a powerful weapon against cancer.
