Histological evaluation of PanIN lesions in pancreata from 4-month old (A–D) and 9-month old (E-H) KC and 17KC mice. Representative images from hematoxylin and eosin (A, B, E, F) and quadchrome (simultaneous Alcian Blue and Sirius Red staining; C, D, G, H) stains are shown. (I) Quantification of normal and neoplastic cell types as a percentage of total tissue area. The quadchrome stain marks collagen red, mucin blue, cytoplasm yellow-brown, and nucleic acids black. Arrowheads identify examples of PanIN lesions. Ac = Acinar tissue. Number of organs (n) analyzed for each group were 4 mo KC (4), 4 mo 17KC (7), 9 mo KC (3), 9 mo 17KC (2). Scale bar = 0.25 mm. p values by Student's t test: * < 0.05, ** < 0.01. Error bars represent standard deviation from the mean.