α2 Integrin-Dependent Suppression of Pancreatic Adenocarcinoma Cell Invasion Involves Ectodomain Regulation of Kallikrein-Related Peptidase-5

Figure 6

α2 and KLK5 are expressed in normal pancreatic ductal epithelium and reduced or absent in poorly differentiated PDAC. (Upper Panels) (A) Normal pancreas stained for α2 showing positive ducts and ductules. (a) Higher power image of (A). (B) Well-differerentiated PDAC showing α2 positivity. (b) Higher power image of (B). (C) Moderate- to poorly differentiated PDAC showing reduction/loss of α2 in the more poorly differentiated cells. Asterisk denotes a benign reactive duct within the tumor region. (c) Higher power image of (C). (D) Poorly differentiated α2-reduced/negative PDAC cells (black arrowhead) invading the wall of the duodenum (DW) with adjacent α2-positive noninvading well-differentiated ducts. (d) Higher power image of (D). (E) Poorly differentiated α2-reduced/negative PDAC cells (black arrowhead) invading the lymph node (LN), with adjacent α2-positive non invading well-differentiated ducts. (e) Higher power image of (E). (Lower panels) (F) Normal pancreas stained for KLK5 showing ducts and ductules positive (in addition to acinar cells and some signal in islets). (f) Higher power image of (F). (G) Well-differentiated ducts showing KLK5 positivity. (g) Higher power image of (G). (H) Well- to moderately differentiated KLK5-positive ducts with adjacent less differentiated, KLK5-reduced/negative cells (black arrowhead). (h) Higher power image of (H). (I) A field of poorly differentiated/anaplastic PDAC cells (black arrowhead) with adjacent clusters of KLK5-positive cells (white arrowheads); low power. (i) α2 staining of a serial section of (I). (J) Higher power image of KLK5 staining in I. (j) Higher power image of α2 staining in (i).