IAPP and Alzheimer disease: We found that pro-IAPPβ, pro-IAPPγ, and fs-IAPPγ determined by SRM could effectively discriminate between AD and controls, with AUROC values of 0.89 (p = 0.0006), 0.77 (p = 0.018), and 0.75 (p = 0.028), respectively (Figure 4E–G), while the performance of the IAPP-ELISA was like chance, with an AUROC of 0.51 (p = 0.93) (Figure 4H).