Fig. 1

CALB2 is overexpressed both in CAFs and cancer cells and correlates with immunosuppressive TME. (A) UMAP plots of single-cell transcriptome data identified cell-specific expression of CALB2 in human PDAC tissues. (B) Heatmap illustrating the correlations of CALB2 expression with cell infiltration in the TME across multiple PDAC datasets. (C) Representative IHC staining of CALB2, FAP, and CK19 in human PDAC tissues. Black arrows indicate CALB2⁺CK19⁺FAP⁻ cancer cell and red arrows indicate CALB2⁺CK19^–FAP⁺ CAF. Scale bars, 200 μm (top), 50 μm (bottom). (D) Scatter plot demonstrating the correlation between the IHC mean density of CALB2 and FAP or CK19. (E) Tissue-based cyclic immunofluorescence for CALB2 (pink), FAP (orange), CK19 (green), in human PDAC tissues. Scale bars, 50 μm (top left), 20 μm (top right and bottom). (F) Comparison of the indicated cell types in matched cancer and adjacent tissues. (G) Comparison of the indicated cell types in tumors without or with metastasis. (H) Human PDAC tissues were classified into CALB2-High or CALB2-Low groups (left), cancer cell CALB2-High or CALB2-Low groups (middle), or CAFs CALB2-High or CALB2-Low groups (right), based on the cyclic immunofluorescence, followed by examining patient overall survival using Kaplan-Meier survival analysis. (I) Representative CALB2 and PD-L1 IHC staining in human PDAC tissues, and quantification of PD-L1 positive cells area per field (n = 36). Scale bars, 100 μm. (J) CALB2 IHC and Sirius Red staining in human PDAC tissues and quantification of collagen deposition using Sirius Red staining (n = 36). Scale bars, 50 μm. Error bars, mean ± SD; *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001; ns, not significant; by Pearson’s correlation test (D), paired t test (F), Student’s t test (G, I, and J) or log-rank test (H)