In cancer cells, invasion activity is associated with the presence of specific matrix-degrading, cell adhesion structures called invadopodia [51, 52]. Invadopodia can be identified by the organization of their core cytoskeletal protein components–actin and cortactin–into punctate or rosette-shaped structures that are functionally associated with localized sites of elevated metalloproteinase activity [51, 53–55]. To better understand the nature of the invasive defect that we observed in 17KPC cell lines, we analyzed invadopodia formation by immunofluorescence. We found that invadopodia in KPC and 17KPC cell lines take the form of rosettes and that KPC cell lines display significantly higher rates of invadopodia rosette formation than 17KPC lines (Figure 6A–6I). In agreement with reduced invadopodia numbers, 17KPC cell lines also degrade less FITC-labeled gelatin matrix than KPC lines (Figure 6J–6N). These data suggest that loss of mir-17~92 decreases invasion, at least in part, as a result of reduced matrix-degrading capacity.