When no Pten allele was deleted (KrasG12D;Pten+/+), hepatocellular dysplasia was formed, with no abnormalities in the biliary system; in contrast, deletion of both Pten alleles (KrasG12D;Pten∆/∆) produced only iCCA; while deletion of just one Pten allele (KrasG12D;Pten∆/+) produced both HCC and iCCA. The gene discussed is PTEN; the disease is hepatocellular carcinoma.