Abstract 470: Appropriateness of long-term culture of patient-derived tumor organoid for colorectal cancer modeling through genetic and phenotypic profiling

Abstract Background and Objective: Colorectal cancer (CRC) is one of the leading causes of cancer-related morbidity and mortality worldwide, requiring effective disease models to study its progression and develop novel therapeutics. This study aimed to establish a long-term patient-derived tumor organoid (PDO) model and evaluate its suitability for colorectal cancer modeling through comprehensive genetic, morphological, and molecular analyses. Methods: PDOs were cultured for 1, 3, and 6 months to mimic the progression of CRC. Chromosomal instability was assessed using karyotyping, and morphological changes were evaluated through hematoxylin and eosin (H&E) staining and bright-field imaging. Immunofluorescence staining was performed for the colorectal stem cell marker LGR5 and the epithelial differentiation marker CDX2, which is specifically expressed in the small intestine and colon epithelium and plays a key role in epithelial growth and differentiation. Temporal changes in genetic instability, structural characteristics, and marker expression were analyzed to validate the model. Results: Karyotyping revealed a progressive increase in chromosomal instability across the 1-, 3-, and 6-month PDOs, consistent with CRC-associated genetic alterations. Morphological analysis using H&E staining and bright-field imaging demonstrated gradual structural changes, with the 6-month PDOs displaying histological features characteristic of CRC. Immunofluorescence staining showed a decline in LGR5 expression over time, reflecting reduced stemness in advanced stages, while CDX2 expression was maintained across all time points, indicating its critical role in epithelial differentiation during cancer progression. Conclusion: The long-term PDO-based model successfully recapitulates the genetic, morphological, and molecular hallmarks of colorectal cancer progression. This model captures key transitions, including chromosomal instability, structural alterations, and dynamic marker expression, while retaining essential epithelial markers like CDX2. These findings underscore the potential of PDOs as a robust in vitro platform for studying colorectal cancer development and progression and advancing therapeutic research. Citation Format: Jaemin Cho, Eun Ah Jung, Hyowon Hong, Sang Joon Byun, Sung Wook Bae, Inchul Seo, Jumgsook Ha, Hyewon Lee, Shin Kim. Appropriateness of long-term culture of patient-derived tumor organoid for colorectal cancer modeling through genetic and phenotypic profiling [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 470.