β-Catenin and Cyclin D1 in Mucoepidermoid Carcinoma of Variable Histologic Grades.

Objective To analyze the expression of β-catenin and cyclin D1 in mucoepidermoid carcinoma (MEC) of variable histologic grades to establish a correlation between the expression of these proteins and the different histopathologic grades of this neoplasia. Design Immunohistochemical analysis of MEC. Setting Pathological Anatomy Service, Discipline of Oral Pathology, Department of Dentistry, Federal University of Rio Grande do Norte, Natal, Brazil. Patients Fifteen cases of MEC, graded and categorized according to criteria reported in the literature into 5 tumors with a low grade of malignancy, 4 with an intermediate grade, and 6 with a high grade. Main Outcome Measures Labeling patterns of β-catenin and cyclin D1. Results No significant difference in β-catenin labeling patterns was observed between low- and intermediate-grade tumors or between low- and high-grade tumors (P = .60 and P = .06, respectively; Fisher exact test), despite a strong tendency toward a difference in the latter. In contrast, a significant difference was noted between intermediate- and high-grade tumors (P = .03). For cyclin D1, no labeling was observed in any high-grade cases, and only 3 cases showed overexpression of this protein. Comparison of the labeling patterns among the different histologic grades revealed no significant difference. Conclusions The reduced expression of β-catenin observed in all high-grade MECs is probably due to the loss of its adhesion function, which confers a greater invasive potential to these tumors. The overexpression of cyclin D1 observed in only 3 MEC cases suggests that this protein does not participate in the etiopathogenesis of these tumors, which implies that other genes are likely responsible. [ABSTRACT FROM AUTHOR]

Copyright of Archives of Otolaryngology - Head & Neck Surgery is the property of American Medical Association and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)