AI-Designed Antibody Targets Cancer Mutation Inside Cells

Antibodies are like “guided missiles” that find and attack cancer cells, but cancer-causing mutations inside cells have remained a “blind spot” for treatment because antibodies cannot reach them. KAIST researchers have now succeeded in precisely targeting even intracellular cancer mutations using a newly designed antibody created through computational methods. This achievement is expected to open a new path toward next-generation precision therapies for difficult-to-treat cancers, going beyond the limitations of conventional antibody treatments.

KAIST (President Choongsik Bae) announced on the 24th of July that a research team led by Professor Byung-Ha Oh from the Department of Biological Sciences, together with researchers from Therazyne, a KAIST faculty startup specializing in protein design and headed by Professor Oh, has developed an antibody that selectively recognizes only cancer cells carrying KRAS(G12D), a representative cancer-driving mutation. By combining computational antibody design with experimental validation, the team designed a new antibody that would have been difficult to develop through conventional approaches and is now verifying its efficacy in animal disease models.

KRAS(G12D) is a mutated form of the KRAS protein, which regulates cell growth and proliferation. It is one of the most common cancer-driving mutations found in pancreatic, colorectal, and lung cancers. However, because the KRAS protein exists inside cells, it has long been considered an “undruggable target” that is difficult to directly target with conventional antibody therapeutics.

The research team focused on the natural process by which cells break down aged or damaged proteins into small fragments. The KRAS(G12D) protein inside cells is also processed in this way into small protein fragments, known as neoantigens, which serve as clues that allow immune cells to distinguish cancer cells. Some of these fragments are then transported to the cell surface and presented to immune cells. By combining computational protein design with experimental screening, the team developed a TCR-like antibody that precisely recognizes only this cancer-mutation-derived fragment.

TCR, or T cell receptor, acts as a “sensor” that allows T cells, the body’s immune cells, to read protein fragments displayed on the surface of cells and identify cancer cells or virus-infected cells. The TCR-like antibody developed in this study works on a similar principle, effectively giving an antibody the “eyes” of a T cell. It was designed to selectively recognize traces of intracellular cancer mutations that conventional antibodies cannot easily access.

Experimental results confirmed that the antibody developed by the team selectively recognizes only cancer cells carrying the KRAS(G12D) mutation, while showing little to no reaction with normal cells or other proteins. When applied to immunotherapy, it was also shown to effectively eliminate only cancer cells carrying the mutation. This finding suggests the possibility of expanding antibody therapy to intracellular cancer-driving proteins that conventional antibody treatments have been unable to target. It is also expected to serve as a platform technology for developing next-generation precision antibody therapies targeting not only KRAS but also a wide range of cancer mutations.

Professor Byung-Ha Oh said, “The antibody developed in this study can selectively identify only cancer cells carrying the KRAS(G12D) mutation, demonstrating the potential for precision antibody therapeutics that minimize damage to normal cells.” He added, “The computational antibody design technology developed in this research is expected to be widely applicable to the development of next-generation antibody therapeutics targeting KRAS as well as various other cancer mutations.”

Reference: Ahn S, Oh TS, Suh S, et al. Discovery of TCR-like antibodies to the KRAS G12D neoantigen via in silico-in vitro workflow. Mol Ther. 2026:S1525001626004776. doi: 10.1016/j.ymthe.2026.05.032

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