CASP4 and pancreatic adenocarcinoma: We constructed a prognostic index for all cancer samples calculated by the formula: Risk score = expression level of IL18 × 0.002067 + expression level of GSDMC × 0.034755 + expression level of NLRP2 × 0.028693 + expression level of PLCG1 × (− 0.00285) + expression level of NLRP1 × (− 0.05665) + expression level of CASP4 × 0.036385. In order to confirm whether this pyroptosis-related model could predict the prognosis of patients with PAAD, we divided the 170 patients into a high-risk group (n = 85) and a low-risk group (n = 85) according to the threshold of median risk score (Fig. 4A).