Fig. 1: GATA6 expression associates with immunoreactive stroma in human PDAC.

Phenotypic profiles of PDAC patients with differential GATA6 tumor expression at a protein and b transcriptomic levels. GATA6 expression in tumor epithelial cells in a TMA from PDAC resections (n = 143 biological replicates) was assessed by IHC. Epithelial regions were manually annotated for each of the 594 cores by a trained pathologist before GATA6 expression was digitally quantified. All cores per patient were averaged and patients categorized into GATA6^high, GATA6^intermediate, or GATA6_low groups by expression quantiles. CD8, CD4, CD20, CD68, FOXP3 were stained by IHC in resections (n = 143 biological replicates) and quantified by QuPath bioimage analysis software. Expression levels of tumor-infiltrating (TILS) CD3 and CD8, CD20, CD68, CD4 and FOXP3 in each group are shown. Box plots show the median (center line), 25th–75th percentiles (bounds of box), and whiskers extending to the minima and maxima values. Individual data points represent independent patients. Statistical significance was calculated by Wilcoxon test. b Maurer et al. dataset (GSE93326, n = 65 biological replicates). Enrichment was tested against the differential expression profile of epithelium GATA6^hi vs GATA6_lo (n = 32 vs n = 32 biological replicates, cutoff: median) in epithelium and their paired stroma samples separately. c Cellular interaction analysis on GATA6^+/− tumor cells in a single-cell RNA-sequencing dataset from Chen et al. (GSE212966, n = 6 biological replicates). Left panel: CellChat analysis of cellular interactions among GATA6^+/− tumor cells and CD20⁺ B cells, CD8⁺ and CD4⁺ T cells, CD68⁺ cells, and Fibroblasts. The line thickness represents the strength of the interaction signals, the direction of the arrows indicates the orientation of the signals. Right panel: GSEA was performed, and selected pathways enriched in GATA6⁺ tumor cells when compared to the GATA6⁻ counterpart were shown. d Multiplex imaging by Phenocycler on human PDAC tissues (n = 8 biological replicates) demonstrated heterogeneous tumor GATA6 expression associated with infiltration of CD4⁺, CD8⁺, CD20⁺, and CD68⁺ cells in the neighborhood (left panel, bar unit: µm). Computational spatial analysis by HALO software showed higher number of immune cells in close proximity (<50 μM radical distance) of GATA6⁺ tumor cells than the GATA6⁻ counterparts (n = 8 biological replicates) (right panel). Statistical significance was calculated by two-tailed Wilcoxon matched-pairs signed rank test. e GATA6⁺ tumor cells (GATA6⁺PanCK⁺) express higher level of MHCI (HLA-A) than their negative counterpart (GATA6⁻PanCK⁺). Quantification was done by HALO software (n = 8 biological replicates). Bar unit: µm. Statistical significance was calculated by two-tailed Wilcoxon matched-pairs signed rank test.