Objective to construct a risk prediction model by integrating The molecular subtypes of pancreatic ductal adenocarcinoma(PDAC)and immune-related genes.Methods with GSE71729 data set(n=145)as the training set,the differentially expressed genes and differential immune-related genes between the squamous and non-squamous subtypes of PDAC were integrated to construct a regulatory network,on the basis of which five immune marker genes regulating the squamous subtype were screened out.an integrated immune score(IIS)model was constructed based on patient survival information and immune marker genes to predict the clinical prognosis of PDAC patients,and its predictive performance was tested With 5 validation sets(n=758).Results PDAC patients were assigned into high risk and low risk groups according to the IIS.in both training and validation sets,the overall survival of patients in the high risk group was shorter than that in the low risk group(both P<0.001).the multivariable Cox regression showed that IIS was An independent prognostic factor for PDAC(HR=2.16,95%CI=1.50-3.10,P<0.001).Conclusion IIS can be used for risk stratification of PDAC patients and may become a potential prognostic marker for PDAC。