KRAS and neoplasm: To screen the differential genes between normal and KRAS wild-type PAAD samples, we analyzed the differential genes between 171 normal samples and 70 KRAS wild-type tumor samples using the “limma” package, and obtained a total of 2,928 significantly DEGs, of which 2029 were down-regulated and 1,163 were up-regulated in tumors (FDR <0.01, |log2FC| > 2, Figure 2A).