Fig 1: Establishment and characterization of a CAF-enriched PDAC tumor microenvironment model(A and B) Immunofluorescence staining showing co-expression of CAF markers α-SMA and FAP in PSCs. Scale bars, 200 μm. (C and D) Flow cytometry analysis comparing expression levels of α-SMA and FAP between tumor-derived CAFs and PSCs. (E) Schematic of the CAF-enriched PDAC model establishment by subcutaneous co-injection of KPC cells with PSCs at a 1:10 ratio. Tumors were harvested for flow cytometry analysis when the volume reached 1,000 mm3. Created by BioRender. (F) Quantification of the percentage of CAFs in the tumor microenvironment (TME) of the 1:10 Mixture model compared to the KPC tumor model. (G and H) Sirius red staining of tumor sections showing increased collagen deposition in the 1:10 Mixture model compared to the KPC tumor model. Scale bars, 200 μm. (I) Heatmap showing the expression levels of classical CAF marker genes (e.g., FAP, ACTA2, COL1A1) in the 1:10 Mixture group and human pancreatic cancer samples from the dataset GEO: GSE71729. (J) Principal-component analysis based on CAF marker genes in both the 1:10 Mixture and Human groups. (K) CAF signature scores in the 1:10 Mixture and Human groups. Data are presented as mean ± SEM. Statistical significance was assessed using a t test (ns, not significant; ∗p < 0.05; ∗∗p < 0.01; ∗∗∗p < 0.001; ∗∗∗∗p < 0.0001).