EGFR and pancreatic ductal adenocarcinoma: Abbreviations: AUC = area under the ROC curve, BMI = body mass index, CA19-9 = serum tumor-associated carbohydrate antigen 19-9, CI = confidence interval, DAB = diaminobenzidine, ECs = endothelial cells, EGFR = epidermal growth factor receptor, HR = hazard ratio, NLR = neutrophil-lymphocyte rate, PDAC = pancreatic ductal adenocarcinoma, PLR = platelet-lymphocyte rate, ROC curve = receiver operating characteristic curve, TF = tissue factor, TNFAIP3/A20 = tumor necrosis factor alpha-induced protein 3, TNM = tumor lymph node metastasis.