Figure 9

Immunohistochemical analysis and staining of PFK-1 in normal oral mucosal tissue, oral precursor lesions - hyperplasia, SIN I, SIN II, SIN III, and invasive OSCC. In comparison with normal tissue a significantly increased expression of PFK-1 expression is observed in SIN I and SIN II lesions (p < 0.05, Kruskal-Wallis Test; A and B). In comparison with SIN I, SIN II, and SIN III (sev. dysplasia) a significantly decreased expression of PFK-1 expression is observed in OSCC. PFK-1 expression is significantly decreased in OSCC compared with SIN I-III (p < 0.0001, Mann–Whitney U Test). Analysis refers to averaged scores. Red line indicates PFK-1 expression results during carcinogenesis. Grey lines show 95% confidence intervals. Analysis of significant statistically different single values is indicated in the table below (B). SIN III is subdivided in severe dysplasia and carcinoma in situ (CIS). PFK-1, phosphofructokinase-1; SIN, squamous intraepithelial neoplasia; N.T., normal tissue. Immunohistochemical staining shows representative images of PFK-1 expression in N.T. (C), SIN (D), and OSCC (E). Brown chromogen color (3,3′-Diaminobenzidine) indicates positive staining, the blue color shows the nuclear counterstaining by hematoxylin. The square box demonstrates the area of interest (original magnification: x100-fold, left panel) which is also shown in larger magnification (x200-fold, right panel).