Figure 2

Expression pattern of integrin receptors and type IV collagen in pancreatic cancer tissue. A. H&E staining of representative areas of a well (in B) and moderately (in C) differentiated pancreatic adenocarcinoma. Clusters of tumor cells (T) surrounded by desmoplastic stroma (D). B. Merged immunofluorescence double staining of integrin α₁, α₂, and β₁ (in red), and type IV collagen (green in upper row), or the endothelial marker CD31 (green in lower row). Type IV collagen is highly expressed in close vicinity to the cancer cells, forming BM like structures around small clusters of cancer cells. Integrin α₂ and β₁ are expressed on cancer cells, and these receptors colocalize with type IV collagen (in yellow). Integrin α₁ and β₁ are expressed in the endothelial basement membrane, as indicated by colocalization with CD31. C. In moderately differentiated cancer the same expression pattern as in well differentiated cancer can be seen, but integrin α₁ is sporadically expressed in cancer cells. Close-up in inserts (magnification x100), all other panels with a magnification of x40. Arrows indicate examples of colocalization. Cell nuclei are stained by DAPI (in blue).