p53 and p16 in oral epithelial dysplasia and oral squamous cell carcinoma: A study of 208 cases

BACKGROUND: The use of p16 and p53 as biomarkers of malignant transformation of oral epithelial dysplasia (OED) and biological behavior of oral squamous cell carcinoma (OSCC) is controversial. AIM: To determine the immunoexpression of p16 and p53 in OED and OSCC and to establish their possible relation to histopathological grading of OED/OSCC. MATERIALS AND METHODS: Ninety-six OEDs (40 mild, 36 moderate, and 20 severe dysplasia); and 112 OSCCs (64 well-differentiated, 38 moderately differentiated, and 10 poorly differentiated) coming from archives of four centers of oral pathology were included. Histological slides from all cases were processed with immunohistochemical technique using anti-p53 and anti-p16 antibodies. The intensity of the immunoreactivity were classified using the ImageLab®MCM systemas follows: <60 mild, >60-<90 moderate, and >90 strong. Forstatistical purposesa χ2 test (P < 0.05) was performed. RESULTS: Severe dysplasia show highest relative frequency of p16-positive (35.5%), whereas p53 is associated with mild dysplasia (P = 0.04). Moderately differentiated OSCC had larger relative frequency of p16-positive and p53-positive cases (47.3% both circumstances) (P > 0.05). Statistical association of p16-positive and p53-positive cells to basal stratum of OED (P = 0.0008; P = 0.0000, respectively) and p16-positive cells and p53-positive cells to perivascular zone of OSCC (P = 0.001; P = 0.0000, respectively) was found. CONCLUSIONS: p16 and p53 could be not specific enough to identify patients suffering OED with high risk to malignancy; however, the evaluation of the presence of p16 and p53 in the tumoral invasive front of OSCC could contribute to establish the tumor progression.