Figure 6

Immunohistochemical analysis and staining of SDHA in normal oral mucosal tissue, oral precursor lesions - hyperplasia, SIN I, SIN II, SIN III, and invasive OSCC. In comparison to normal tissue/hyperplasia a significantly (p < 0.05, Kruskal-Wallis Test; A and B) increased expression of SDHA is observed in OSCC. SDHA expression is significantly increased in OSCC compared with SIN I-III (p = 0.0103, Mann–Whitney U Test). Analysis refers to averaged scores. Red line indicates SDHA expression results during carcinogenesis. Grey lines show 95% confidence intervals. Analysis of significant statistically different single values is indicated in the table below (B). SDHA is subdivided in severe dysplasia (sev. dysplasia) and carcinoma in situ (CIS). SDHA, succinate dehydrogenase A; SIN, squamous intraepithelial neoplasia; N.T., normal tissue. Immunohistochemical staining shows representative images of SDHA 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).