Correlation of expression of nuclear proteins pKi67 and p63 with lectin histochemical features in head and neck squamous cell cancer

This study represents a combined lectin and immuno-histochemical analysis of normal, dysplastic and malignant squamous epithelia of the upper aerodigestive tract with emphasis on the relation between lectin reactivity and the cells' proliferative/anti-apoptotic potential. Staining by double-labeling to detect pKi67, ΔNp63α, α2,3/6-linked sialic acid (NeuNAc) and galectin-3-reactive epitopes was performed on specimens of 8 normal cases, 27 primary tumours and 15 regional lymph node metastases. Normal epithelia expressed α2,6-linked NeuNAc in the basal layer, while α2,3-linked NeuNAc was observed in suprabasal layers. In normal epithelium pKi67 and ΔNp63α positivity was seen in the basal layer and galectin-3-reactive sites in suprabasal layers. The studied squamous cell carcinomas and their metastases showed a tendency for stratification but with markedly altered architecture. The expression of the studied markers was heterogeneous between the different cancer cases but comparable between the corresponding primary and secondary lesions. Glycophenotypic properties were correlated with the level of differentiation. Tumour cell populations were characterized by occurrence of the p63+/pKi67+ α2,3-NeuNAc+ α2,6-NeuNAc+ phenotype. Analysis of the expression patterns of pKi67, p63 and galectin-3-reactive epitopes (Gal-3-RE) delineated statistically significant interrelationships (Gal-3-RE vs. p63: r=-0.709; Gal-3-RE vs. pKi67: r=-0.623; pKi67 vs. p63: r=0.895). Of the studied markers only Gal-3-RE expression was correlated to the differentiation-dependent grading (G1 vs. G2: p=0.007, G2 vs. G3: p=0.006, G1 vs. G3: p=0.002). ΔNp63α expression was statistically different only between G1 and G3 (p=0.03). No statistically significant differences were detected between the primary tumours and the corresponding regional lymph node metastases. Based on the concept of the sugar code further analysis of cell characteristics such as proliferation together with lectin histochemical features, especially using tissue lectins as probes, is thus warranted.