microRNA-21 in the PDAC stroma is expressed in activated myofibroblasts.

(A) miR-21 in situ hybridization and co-immunofluorescence for α-SMA and nestin on serial sections of two human PDAC tumors (Whipple resection - WR 22 & 28) reveals miR-21 expression in a subset of activated myofibroblasts, not exclusive to stellate cells (nestin positive). miR-21 positive staining is white in the merge. (B) High-power magnification (40x) again reveals miR-21 expression in a subset of α-SMA expressing myofibroblasts. Vimentin, a marker for quiescent fibroblasts, does not localize with miR-21.