Beta-catenin and cyclin D1 in mucoepidermoid carcinoma of variable histologic grades.
OBJECTIVE
To analyze the expression of beta-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.


METHODS
Immunohistochemical analysis of MEC.


METHODS
Pathological Anatomy Service, Discipline of Oral Pathology, Department of Dentistry, Federal University of Rio Grande do Norte, Natal, Brazil.


METHODS
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.


METHODS
Labeling patterns of beta-catenin and cyclin D1.


RESULTS
No significant difference in beta-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 beta-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.
Miguel
Márcia Cristina da Costa
MC
Laboratory of Oral Pathology, Dentistry School, Federal University of Rio Grande do Norte, Natal, Brazil.
Oliveira
Márcio Campos
MC
Seabra
Flávio Roberto Guerra
FR
Queiroz
Lélia Maria Guedes
LM
Freitas
Roseana de Almeida
Rde A
Batista de Souza
Lélia
L
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018277:Carcinoma, Mucoepidermoid / Q000378:metabolism / Q000473:pathology*; D002648:Child; D019938:Cyclin D1 / Q000378:metabolism*; D003598:Cytoskeletal Proteins / Q000378:metabolism*; D005260:Female; D006801:Humans; D007124:Immunoenzyme Techniques; D008297:Male; D008875:Middle Aged; D013194:Staining and Labeling; D018709:Statistics, Nonparametric; D015534:Trans-Activators / Q000378:metabolism*; D051176:beta Catenin
C495270:CTNNB1 protein, human; D003598:Cytoskeletal Proteins; D015534:Trans-Activators; D051176:beta Catenin; D019938:Cyclin D1