KRT19 and neoplasm: H&E staining displayed that tumor cells were arranged as lumen-like structures with moderate to severe nuclear atypia (Figure 7A) and inflammatory cells were infiltrated in PC stroma, Masson staining showed that fibrosis of tumor tissue is more obvious than that in adjacent tissue (Figure 7A), and IHC staining revealed that the expressions of four model genes including KRT7, KRT19, IGF2BP3 and CXCL5 were all higher in tumor tissues than those in adjacent tissues (Figure 7A), which were consistent with the results of our bioinformatics analysis.