Avaliação da expressão imunoistoquímica das proteínas β-catenina e wnt-5a em carcinoma escamocelular de boca

Abstract

Oral squamous cell carcinoma (OSCC) is the most common histological form of head and neck cancer. Because of the highly aggressive evolution of some tumors, more knowledge is needed about its biological behavior, which may be achieved using immunohistochemical markers. Wnt-5a, of the Wnt family, is frequently upregulated in certain human cancers, and it can regulate gene expression through a mechanism dependent on β-catenin. So, the aim of this study was to evaluate immunoexpression of β-catenin and Wnt-5a proteins in OSCC. Thirty six OSCC lesions were graded according to WHO diagnostic criteria for histological typing of cancer. The immunohistochemistry was performed in line with the Streptavidina-biotin method. β-catenin protein expression had a higher membrane expression pattern in well differentiated tumors (66.67%), while moderately and poorly differentiated tumors showed a predominance of cytoplasmic expression pattern with less than 20% in the nuclei. Furthermore, Wnt-5a expression was observed in most of the sample (86%) with more than 70% of their cells marked, usually in a cytoplasmic expression pattern (61.11%). It was also verified that tumors with low intensity Wnt-5a expression had lower mean percentages of marked cells (ANOVA, p=0.000). There was also a statistically significant difference between the mean percentage of marked cells in the palate compared with the tongue, mouth floor and lower alveolar ridge (ANOVA, p=0.004). The study found no influence of Wnt-5a on the β-catenin signaling. It seems that the studied proteins play an independent role in OSCC.