Figure 1

A representative immunohistochemical analysis of NGAL during the pathogenesis of the pancreatic gland. Representative sections of formalin-fixed, paraffin-embedded tissues immunolabelled with polyclonal anti-NGAL antibody using the horseradish peroxidase detection method with DAB substrate. Brown-coloured product indicates positive immunoreactivity. (A) Neutrophil gelatinase-associated lipocalin expression in normal pancreas, acute pancreatitis, and well-, moderately, and poorly differentiated pancreatic adenocarcinoma. The normal and pancreatitis tissue samples presented a weak staining in the small and small/medium size ducts, respectively. For pancreatic adenocarcinoma, a gradient of NGAL expression was detected from strongest in well-differentiated tumours to absent staining in poorly differentiated tumours. (B) Correlation of NGAL expression with pancreatic cancer progression. Neutrophil gelatinase-associated lipocalin positivity was identified in the premalignant PanIN lesions as early as PanIN-1. Pancreatitis surrounding the cancer stained as strongly as the PanIN areas. The staining intensity was weaker in the well-differentiated adenocarcinoma (top panel: original magnification × 10 and bottom panel: original magnification × 20). All sections were counterstained with haematoxylin.