In a well-differentiated pancreatic cancer double-stained with CK19 (Figure 5G), we could demonstrate a similar staining pattern as seen in the normal pancreas in areas where acini and ducts connect: Cytoplasmic CK19 was co-expressed with membranous CD133 in apical/endoluminal cells lining the ductal lumen whereas some cells expressed cytoplasmic CD133, but not CK19, at the site of solid growth. Here, PROM1 is linked to familial pancreatic carcinoma.