Of 122 primary human resected PDAC, fascin was absent from normal ductal and acinar tissue, but prominent in PDAC cytoplasm (Figure 1A). Ninety-five percent of human PDAC expressed fascin and a high histoscore significantly correlated with decreased overall survival ( Figure 1B), PS-341 in vitro high tumor grade ( Figure 1C; median histoscore 104.4 vs 72.8; P < .05), and vascular invasion ( Figure 1D; median histoscore 94.5 vs 62.2; P < .04). Fascin levels did not correlate with lymph node status, tumor stage,

perineural invasion, and lymphatic invasion (data not shown). In a multivariate Cox proportional-hazards regression analysis, high fascin expression only reached borderline significance as an independent predictor of poor survival, with a hazard ratio of 0.663 (95% confidence interval: 0.44−1; P = .05) ( Supplementary Table 1). Importantly, fascin levels strongly

correlated with time to recurrence, indicating potential importance as a predictor of tumor dissemination ( Figure 1E; P < .0005). To explore a functional role of fascin, we used a mouse model of pancreatic cancer (KPC mice) recapitulating both pre-invasive PanIN (grade 1−3) and invasive, metastatic PDAC.4 Wild-type ducts and acini and PanIN1−2 from 10-week-old KPC mice were negative for fascin (Figure 1F). Around 6% of PanIN3 and 100% of PDAC (both 10-week and advanced tumors) ( Supplementary

Table 2) were fascin positive ( Figure 1F) small molecule library screening and fascin was expressed in both well and poorly differentiated areas (data not shown). Fascin null mice had normal-sized pancreata with no apparent changes in tissue structure or proliferation (Supplementary Figure 1). Although fascin is weakly expressed ADP ribosylation factor by a few cells in the islets of Langerhans (Figure 1F), fascin null mice had normal peripheral blood levels of several markers indicating normal pancreatic function ( Supplementary Table 3). Development of PanIN in KrasG12D or KrasG12D and p53R172H expressing pancreata was not changed by loss of fascin ( Supplementary Figure 2). Loss of fascin also did not affect progression, morphology, or proliferation of cells in an acute model of pancreatitis using cerulein injection ( Supplementary Figure 3). However, by 21 days of cerulein treatment, fascin was detected in stroma and epithelium of PanIN of KC animals ( Supplementary Figure 3). However, loss of fascin did not affect the numbers of monocytes, lymphocytes, or neutrophils recruited to acute PanINs, revealing no gross abnormalities in the immune response to PanIN in the fascin null mice ( Supplementary Figure 3E and F). In summary, fascin expression was detected in a minority of PanIN3 and all PDAC and loss of fascin did not detectably affect pancreas development or PanIN.