Assessment of CTNNB1 gene mutations and β-catenin immunoexpression in salivary gland pleomorphic adenomas and adenoid cystic carcinomas

• Published in: Virchows Archiv : an international journal of pathology Vol. 472; no. 6; pp. 999 - 1005
• Main Authors: Cavalcante, Roberta Barroso, Nonaka, Cassiano Francisco Weege, Santos, Hellen Bandeira de Pontes, Rabenhorst, Silvia Helena Barem, Pereira Pinto, Leão, de Souza, Lélia Batista
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01-06-2018; Springer Nature B.V
• Subjects: Adenoid; Cancer; Carcinoma; CTNNB1 gene; Localization; Medicine; Medicine & Public Health; Mutation; Neoplasms; Nuclear transport; Oral cancer; Original Article; Pathogenesis; Pathology; Polymorphism; Salivary gland; Signaling; Solid tumors; Translocation; Tumors; β-Catenin; Immunohistochemistry; β-Catenin; Mutation; Pleomorphic adenoma; Adenoid cystic carcinoma; Salivary gland neoplasm
• ISSN: 0945-6317; 1432-2307
• DOI: 10.1007/s00428-018-2335-z

β-Catenin exerts multiple functions in several neoplasms, playing a major role in cell signaling and tumor progression. This study analyzed possible
CTNNB1
mutations in salivary gland pleomorphic adenomas (PAs) and adenoid cystic carcinomas (ACCs), and determined possible differences in β-catenin immunoexpression in relation to these mutations, as well as histopathological aspects of these tumors. Twenty-four PAs (15 cell-rich and 9 cell-poor tumors) and 24 ACCs (10 tubular, 8 cribriform, and 6 solid tumors) were selected for the analysis of β-catenin distribution and cellular localization. Furthermore, β-catenin expression was evaluated using the H-score scoring system. Mutations in
CTNNB1
exon 3 were investigated by the single-strand conformational polymorphism test. Diffuse β-catenin expression was more frequently observed in ACCs compared to PAs (
P
 = 0.008). No significant difference in β-catenin cellular localization was observed between these tumors (
P
 = 0.098). Comparisons between PA and ACC cases revealed a higher median H-score in the latter (
P
 = 0.036). Cell-rich PAs exhibited a trend for higher H-score than cell-poor tumors (
P
 = 0.060), whereas lower H-scores were observed in cribriform ACCs when compared to tubular and solid ACCs (
P
 = 0.042). Mutations in
CTNNB1
were observed in 6 PAs and 7 ACCs, with no significant difference in H-scores for β-catenin according to mutation status (
P
 = 0.135). β-Catenin is important in the pathogenesis of salivary gland PAs and ACCs. In addition,
CTNNB1
exon 3 mutations do not seem to significantly influence β-catenin cytoplasmic/membranous expression or nuclear translocation in these tumors.