Typing of pancreatic cancer-associated fibroblasts identifies different subpopulations

Figure 2 Cytoglobin expression in the normal pancreas and in pancreatic cancer. In the normal pancreas, cytoglobin expression was observed. A: In periacinar quiescent pancreatic stellate cells (cytoglobin immunostaining; scale bars, 50 μm). No co-expression of cytoglobin with; B: The endothelial marker von Willebrand factor (vWf) [double-immunofluorescence (d-IF) of vWF (green) and cytoglobin (red); scale bar, 10 μm]; C: With the histiocyte marker CD163 [d-IF of CD163 (green) and cytoglobin (red); scale bar 10 μm] was observed in the normal pancreas; D: Semi-quantitative mean labelling scores of cytoglobin expression in juxtatumoural cancer-associated fibroblasts (j-CAFs) = 2.5, peripheral cancer-associated fibroblasts (p-CAFs) = 1.1, lobular fibroblasts (l-FBs) = 2.8, and septal fibroblasts = 1.9. Cytoglobin was expressed at significantly higher levels in j-CAFs than in p-CAFs and in l-FBs than in p-CAFs. ^bP < 0.01, ^cP < 0.001; E: Moderate cytoglobin expression in j-CAFs (scale bar, 100 μm); F: In p-CAFs, only barely perceptible cytoglobin expression was observed (scale bar, 250 μm); G: Strong maspin expression in cancer cells surrounded by juxtatumoural stroma (scale bar, 100 μm); H: Peripheral stroma is shown, lacking maspin-positive cancer cells (scale bar, 250 μm). Strong α-smooth muscle actin (α-SMA) expression in I: j-CAFs (scale bar, 100 μm); and J: p-CAFs (scale bar, 250 μm); K: Co-expression of cytoglobin and α-SMA in j-CAFs [d-IF of α-SMA (green) and cytoglobin (red); scale bar, 10 μm]; L: No co-expression of cytoglobin with the endothelial marker vWf in PC [d-IF of vWf (green) and cytoglobin (red); scale bar, 20 μm]; M: No co-expression of cytoglobin with the histiocyte marker CD163 in PC [d-IF of CD163 (green) and cytoglobin (red); scale bar, 20 μm]. j-CAFs: Juxtatumoural cancer-associated fibroblasts; p-CAFs: Peripheral cancer-associated fibroblasts; l-FBs: Lobular fibroblasts; s-FBs: Septal fibroblasts.