The associated publication reports proteogenomic analysis of human pancreatic ductal adenocarcinoma (PDAC), where we provided significantly mutated genes (SMGs)/biomarkers, cellular pathways, and cell types as potential therapeutic targets to improve stratification of patients with PDAC. This protocol describes the detailed methods for mass spectrometry-based proteomic analysis of PDAC samples, including sample preparation, liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis, and data analyses (peptide/protein identification and quantitation).