Immunohistochemical expression of p53, p16 and hTERT in oral squamous cell carcinoma and potentially malignant disorders

• Published in: Brazilian oral research Vol. 25; no. 1; pp. 34 - 41
• Main Authors: Abrahao, Aline Correa, Bonelli, Beatriz Venturi, Nunes, Fábio Daumas, Dias, Eliane Pedra, Cabral, Márcia Grillo
• Format: Journal Article
• Language: English; Portuguese
• Published: Brazil Sociedade Brasileira de Pesquisa Odontológica - SBPqO 01.02.2011; Sociedade Brasileira de Pesquisa Odontológica
• Subjects: Biomarkers, Tumor - analysis; Biomarkers, Tumor - metabolism; Biopsy; Carcinoma, Squamous Cell - metabolism; Carcinoma, Squamous Cell - pathology; Cyclin-Dependent Kinase Inhibitor p16; Cyclin-Dependent Kinase Inhibitor p16 - analysis; Cyclin-Dependent Kinase Inhibitor p16 - metabolism; Dentistry; DENTISTRY, ORAL SURGERY & MEDICINE; Disease Progression; Female; Gene Expression; Humans; Immunohistochemistry; Male; Mouth Mucosa - metabolism; Mouth Mucosa - pathology; Mouth Neoplasms; Mouth Neoplasms - metabolism; Mouth Neoplasms - pathology; Prognosis; Statistics, Nonparametric; Telomerase; Telomerase - analysis; Telomerase - metabolism; Tumor Suppressor Protein p53; Tumor Suppressor Protein p53 - analysis; Tumor Suppressor Protein p53 - metabolism; Mouth Neoplasms; Tumor Suppressor Protein p53; Telomerase; Cyclin-Dependent Kinase Inhibitor p16
• ISSN: 1806-8324; 1807-3107; 1807-3107; 1806-8324
• DOI: 10.1590/s1806-83242011000100007

Oral carcinogenesis is a multi-step process. One possible step is the development of potentially malignant disorders known as leukoplakia and erytroplakia. The objective of this study was to use immunohistochemistry to analyze the patterns of expression of the cell-cycle regulatory proteins p53 and p16(INK4a) in potentially malignant disorders (PMD) of the oral mucosa (with varying degrees of dysplasia) and in oral squamous cell carcinomas (OSCC) to correlate them with the expression of telomerase (hTERT). Fifteen PMD and 30 OSCC tissue samples were analyzed. Additionally, 5 cases of oral epithelial hyperplasia (OEH) were added to analyze clinically altered mucosa presenting as histological hyperplasia without dysplasia. p53 positivity was observed in 93.3% of PMD, in 63.3% of OSCC and in 80% of OEH. Although there was no correlation between p53 expression and the grade of dysplasia, all cases with severe dysplasia presented p53 suprabasal immunoexpression. p16(INK4a) expression was observed in 26.7% of PMD, in 43.3% of OSCC and in 2 cases of OEH. The p16(INK4a) expression in OEH, PMD and OSCC was unable to differentiate non-dysplastic from dysplastic oral epithelium. hTERT positivity was observed in all samples of OEH and PMD and in 90% of OSCC. The high hTERT immunoexpression in all three lesions indicates that telomerase is present in clinically altered oral mucosa but does not differentiate hyperplastic from dysplastic oral epithelium. In PMD of the oral mucosa, the p53 immunoexpression changes according to the degree of dysplasia by mechanisms independent of p16(INK4a) and hTERT.