PDPN and keratoconus: We thus examined the compartment‐specific expression of DKK3 in our mouse pancreatic tissues (KC, harboring two wild‐type Dkk3 alleles versus DKC, carrying one wild‐type Dkk3 allele) at various stages (early to late), using co‐stainings for the epithelial ductal marker CK19 and the pan‐CAF marker PDPN.