PDX1 and keratoconus: To determine whether PPARδ is upregulated in the earlier stages of pancreatic tumorigenesis, we evaluated PPARδ mRNA expression by RNAscope in situ hybridization and protein expression by immunohistochemical (IHC) staining of PanINs in pancreata from patients and KC mice (Pdx1-Cre; LSL-KrasG12D), in which the KrasG12D mutation (KRASmu) is targeted to Pdx1+ pancreatic epithelial cells (Supplementary Fig. 1a).