Fig 1: Pancreatic macrophages and ductal epithelial cells are two HSP90a-expressing cells during PDAC development. (A) Sequential pancreatic tissue sections from 1- or 3-month-old LSL-KrasG12D/Pdx1-Cre mice or 3-month-old LSL-KrasG12D mice were immunohistochemically stained with the antibodies against HSP90a, F4/80, and CK-18, respectively. The example images revealed that HSP90a+ cells were detected abundantly from the pancreatic tissues of LSL-KrasG12D/Pdx1-Cre mice at 3 months of age but not from the pancreatic tissues of 1-month-old LSL-KrasG12D/Pdx1-Cre mice and 3-month-old LSL-KrasG12D mice. These HSP90a-expressing cells included not only F4/80+ cells (macrophages, red arrow) but also CK-18+ cells (ductal epithelial cells, yellow arrows). (B) Example images of immunohistofluorescent staining of patients' PDAC specimens with HSP90a, CD68, and CK-18 antibodies, showing that HSP90a was expressed not only in macrophages (CD68+ cells, white arrows) but also in ductal epithelial cells (yellow arrows).