Researchers have established a new mouse colorectal cancer cell line, called KAP, that carries mutations in Kras, Apc and Trp53 — the three genes most commonly mutated in human colorectal cancer. When implanted into the rectum of mice, the cells form highly aggressive, invasive rectal tumors, according to the study published in BMC Medicine.
The team, led by Maggie L. Lesch and Scott A. Gerber, built the line from colorectal organoids derived from mice harboring the oncogenic KrasG12D mutation and deletion of Trp53. The organoids were then modified to knock out Apc using CRISPR-Cas9. The resulting KAP cells were grown on tissue culture-treated flasks and used in a murine orthotopic rectal model in syngeneic B6 mice, meaning the tumors develop in immunocompetent animals at the anatomical site where colorectal cancer arises in patients.
Preclinical models are essential for developing new treatment strategies, but existing models are limited in the specific tumor subtypes they represent, the authors note in the background of the paper. Colorectal cancer is a highly prevalent and lethal disease, and tumor heterogeneity contributes to varied responses to standard therapies. A model that combines the three most frequent human mutations with an intact immune system addresses a gap in the available toolkit.
Analysis of the KAP tumors by immunohistochemistry showed that they recapitulate several key features of human colorectal cancer, including poorly differentiated gland-like structures, dense areas of collagen deposition, immature vasculature, and a low abundance of intratumoral immune cells. According to the authors, this tumor microenvironment closely resembles immune-excluded colorectal cancer, a subtype known for its resistance to therapy.
To test whether the model also mirrors treatment response, the researchers administered FOLFOX chemotherapy and radiation — standard therapies for colorectal cancer — to mice bearing KAP rectal tumors. They report that the outcomes observed following standard therapy were similar to those seen in patients, suggesting the model can capture clinically relevant therapeutic behavior rather than only tumor architecture.
The combination of specific mutations and microenvironment features is what distinguishes the new line. Many existing models represent only a subset of the genetic alterations found in patient tumors, which can limit how well preclinical findings translate. By contrast, KAP tumors carry the three most common mutations in human colorectal cancer while also displaying the immune-excluded phenotype associated with poor therapeutic response.
The authors state that the establishment of this novel cell line enhances the translational relevance of murine studies for colorectal cancer and provides a valuable tool for studying tumor biology and therapeutic response in the context of low immune infiltration. Because the cells are syngeneic with B6 mice, they can be studied in animals with intact immune systems, which is important for experiments involving immunotherapy or the tumor immune microenvironment.
As with any cell line model, the findings describe a preclinical tool whose behavior was characterized in mice; the reported similarities to patient outcomes come from the therapy experiments conducted in this model, not from clinical trials. The study is an open-access research article published on 28 October 2026, and the version shared is subject to further edits before the final Version of Record appears.
Subject of Research: A novel murine colorectal cancer cell line with Kras, Apc and Trp53 mutations for modeling human colorectal tumors
Article Title: A novel murine colorectal cancer cell line mirroring key clinically relevant mutations
Article References: Lesch, M. L., Zhao, J., Uccello, T. P., Ye, J., Sun, T., Miller, C., Katerji, R., Kothari, M. B., Hannon, G., Eckl, S. L., Hughson, A. L., Chandak, V. S., Vrooman, T. G., Chu, B. H., Qiu, H., Lesser, S., Linehan, D. C., Lord, E. M., Land, H., & Gerber, S. A. (2026). A novel murine colorectal cancer cell line mirroring key clinically relevant mutations. BMC Medicine. https://doi.org/10.1186/s12916-026-05347-0
Image Credits: AI Generated
DOI: 10.1186/s12916-026-05347-0
Keywords: colorectal cancer, KAP cell line, KrasG12D, Apc, Trp53, CRISPR-Cas9, organoids, orthotopic rectal model, tumor microenvironment, immune-excluded, FOLFOX, radiation
News Source: Nathaniel Bowman. (October 28, 2026). New mouse colorectal cancer cell line carries three key human mutations. Scienmag.
