Figure 3. Ptf1a-Cre; βcat^active develop large pancreatic tumors at a high frequency.

Gross morphology of a typical tumor seen in the pancreas of Ptf1a-Cre; β-cat^active, aged 9 months (A, right) compared to a pancreas from a littermate control (A, left). Gross morphology of a cross section of the murine tumor reveals pseudopapillary regions (C, labeled by #) and cystic structures (C, labeled by *). Histological examination of the murine tumor (x12 magnification) show the pseudopapillary regions (E, labeled by #), cystic structures (E, labeled by *) and the pancreatic remnant surrounding the tumor (E, labeled by arrow). Tumors are first detectable in Ptf1a-Cre; β-cat^active mice at 3 months of age. By 12 months of age, nearly 50% of Ptf1a-Cre; β-cat^active mice exhibit tumors (B; n≥8 for each time point examined). Expression of the Wnt target genes, Axin 2 (D) and cyclinD1 (F) are significantly upregulated in the Ptf1a-Cre; β-cat^active pancreas when compared to control pancreas at 9 months of age by RT-PCR. Tumors found in Ptf1a-Cre; β-cat^active mice exhibit a further increase in overexpression of Axin 2 (D) and cyclinD1 (F). Confidence intervals were calculated using student’s t-test, n≥3. P values: #, not significant; *, p<0.05; **, p<0.01. Error bars represent standard deviation.