BACKGROUND: Carcinogenesis is a multifactorial process and inactivation of p53 protein is a genetic change commonly observed in oral squamous cell carcinomas (OSCC). OBJECTIVES: To analyze and compare the expression of p53 protein through antibodies DO-7 and PAb-240 in OSCC samples located in the oral cavity and lower lip. MATERIAL AND METHODS: Forty cases of OSCC were selected and divided into oral cavity and lower lip groups (20 cases each). Immunohistochemical technique was performed using antibodies DO-7 and PAb-240. Quantification of the cases was performed through digital image analysis and underwent specific statistical treatments. RESULTS: Expression of p53 protein was verified with DO-7 antibody in 13 cases (65%) of oral cavity carcinomas and in 19 cases (95%) of lower lip carcinoma. PAb-240 positivity was detected in 9 cases (45%) of oral cavity lesions and in 15 cases (75%) located in the lower lip. According to Mann-Whitney test, there were no statistically significant differences between the expressions of p53 protein in both groups, regardless of the antibody used. According to Wilcoxon test, there were statistically significant differences between the expression of DO-7 antibody and PAb-240 in each of the analyzed groups (p-value = 0.013; lower lip p-value = 0.016 - oral cavity). CONCLUSIONS: The expression of p53 protein was observed both in the oral cavity and lip OSCC, which suggests the occurrence of mutations in TP53 gene. The quantitative differences between the antibodies studied, regardless of the site of the lesions, reflect different specificity between clones DO-7 and PAb-240. Further studies are required to establish the best antibody for p53 protein in oral squamous cell carcinomas.
Squamous cell carcinoma; Oral cancer; Immunohistochemistry; Tumor suppressor protein p53
