We equally divided the patients in the PAAD cohort of the TCGA database into the low- and high-BMP4 groups according to the median expression of BMP4. Subsequently, we determined the differentially expressed genes (DEGs) between the two groups using the “DESeq2” package in R. P-value <0.05 and |log2(Fold Change)|>1 were used as a significance threshold. The gene discussed is BMP4; the disease is pancreatic adenocarcinoma.