Fig. 1: Poor clinical outcomes in pancreatic cancer were associated with high IL-20 expression in patients and targeting IL-20 prolonged survival and inhibited PD-L1 and αSMA expression in KPC mice.

The expression of IL-20 or PD-L1 was analyzed in 72 clinical tissue samples by using immunohistochemical staining. a IL-20 staining was positive in tumor cells and neoplastic ductal epithelial cells in pancreatic tumors but negative in normal ducts (left panel). IL-20 staining was not visible in nonneoplastic ducts (right panel). Scale bar, 50 μm. b Kaplan–Meier analysis of the overall (left panel; n = 72 patients), early-stage (middle panel; n = 41 patients), and late-stage (right panel; n = 31 patients) survival of patients with PDAC with different levels of IL-20 expression was performed. p values, two-sided log-rank test. c PD-L1 staining was visible in the tumor tissue of a patient with PDAC, and the right image shows the enlarged area. Original magnification for images: ×200; scale bar, 50 μm; enlarged area: ×400, scale bar, 20 μm. d The expression of both IL-20 and PD-L1 was analyzed in PDAC tumors (n = 72 patients). Representative images of IL-20 and PD-L1 were analyzed by using the Tissue-Faxs software for IHC quantification and Pearson coefficients for the correlation between IL-20 and PD-L1. p < 0.0001. e IHC staining for IL-20 in pancreases from KPC and WT mice was performed. Original magnification: ×200; scale bar, 50 μm. f Kaplan–Meier survival analysis showed prolonged survival in 7E-treated KPC mice (n = 16). ****p < 0.0001 compared with mIgG-treated controls. g IHC analysis and quantification were performed for Ki-67⁺ proliferating cells in the pancreas of KPC mice treated with PBS, mIgG, or 7E (each group, n = 16). Original magnification: ×200; scale bar, 20 μm. One-way ANOVA, p = 0.0082; *p < 0.05 compared with mIgG-treated controls. IHC staining and quantification were performed for h PD-L1 (one-way ANOVA, p < 0.0001; n = 16) and i αSMA (one-way ANOVA, p < 0.0001; n = 15) expression in tumors from KPC mice. The rightmost panels show IgG-stained negative controls. Original magnification: ×200; scale bar, 50 μm. ****p < 0.0001 compared with mIgG-treated controls. Values represent the mean ± SD. Statistical significance was determined by log-rank test (b, f), two-tailed unpaired t test (d), or one-way ANOVA Sidak’s multiple comparisons test (g–i). The experiments in a, c, e were repeated three times independently with similar results, and the data of one representative IHC images are shown.