PTX3 and neoplasm: Co-expression of Pan-Ck, Ck-7 and PTX3 is restricted to a specific subset of cells (34.5% in PDAC#1; 43.7% in PDAC#3) (Figure 2F, white arrows and Figure 2G, red arrows), compared to the neighbor cells which lack the expression of Ck-7 (Figure 2F, white arrowheads and Figure 2G, red arrowheads), thus suggesting in an attempt to speculate the identification of subpopulation of PDAC cells associated with high tumor metastatic potential.