Pancreatic ductal adenocarcinoma (PDAC) remains one of the deadliest malignancies with few effective treatments and an urgent need for personalized therapeutic strategies. Although patient-derived organoids (PDOs) facilitate drug screening, tissue-derived models often require invasive sampling and suffer from low cellularity and contamination by non-tumor cells. In this study, we developed fluid-derived organoids (FDOs) from malignant effusions as a rapid, minimally invasive, and scalable platform for PDAC research. Organoids were isolated from the pleural effusion and ascitic fluid of patients with PDAC. Histopathological and molecular characterization, including KRAS mutation analysis and CK7 immunostaining, confirmed the tumor origin and biological fidelity. Holotomography was used to characterize organoid morphology and drug response. Drug sensitivity was evaluated using the KRAS G12D inhibitor, MRTX1133. Transcriptomic profiling was performed to identify resistance-associated molecular signatures, and functional validation was used to assess the roles of candidate genes. FDOs were established with a higher success rate, faster growth, and lower non-tumor contamination than conventional tissue-derived PDOs, while faithfully recapitulating the parental tumor histology and genetics. KRAS G12D-mutant FDOs showed marked sensitivity to MRTX1133. Transcriptomic analysis revealed the upregulation of CEMIP , CALB2 , and LY6D in chemo-resistant FDOs, with these genes suppressing apoptosis and conferring gemcitabine resistance in PDAC cells. High expression of this three-gene signature correlated with worse clinical outcomes, underscoring its prognostic and therapeutic relevance. FDOs are an efficient and clinically relevant model for drug sensitivity profiling and biomarker discovery in patients with PDAC. The elevated expression of CEMIP , CALB2 , and LY6D drives chemoresistance and poor prognosis, highlighting their value as predictive biomarkers and potential targets for overcoming pancreatic cancer resistance. As this study is not a clinical trial, please remove the Trial Registration section.
Tae et al. (2026) studied this question.