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

Abstract

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 p16INK4a 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. p16INK4a expression was observed in 26.7% of PMD, in 43.3% of OSCC and in 2 cases of OEH. The p16INK4a 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.

The role of TERT-CLPTM1L SNPs, hTERT expression and telomere length in the pathogenesis of oral squamous cell carcinoma

“…Similarly, Patel et al found no correlation between telomerase activation and clinicopathologic parameters in head and neck cancer (42), while Pannone et al reported higher telomerase activity in OSCC than in normal tissue, although this had no clinicopathologic impact (43). The high incidence of hTERT-positive cases in the present study is consistent with other reports (44,45), and the high expression of hTERT in smaller tumors might be indicative of early telomerase activation. Similarly, Chen at al.…”

Response of peripheral blood mononuclear cells to conditioned medium from cultured oral squamous cell carcinomas

“…The extent of this immunosuppression is often more profound than that observed in patients with other malignancies, 1 and has been postulated to occur in a hierarchical manner. For example, in the latter case, genetic alterations 2 have been found to affect the primary tumor region more than draining lymph nodes. 1 Moreover, immune effector cells obtained from the peripheral blood of patients with cancer, including HNSCC, have been reported to exhibit Declaration of Interests: The authors certify that they have no commercial or associative interest that represents a conflict of interest in connection with the manuscript.…”

Immunocytochemical Study of p53 Protein in Exfoliated Cells of Oral Mucosa in Patients With Type 2 Diabetes

“…Abrahao et al studied the oral mucosal biopsies of patients with leukoplakia, erythroplakia, squamous cell carcinoma and hyperplasia of oral epithelium. They showed that the expression of p53 in these conditions increased (27). Mohtasham et al studied 27 patients with fibrosis hyperplasia, 40 with leukoplakia and 28 with oral squamous cell carcinoma.…”