Twist1 und Snail/Slug: epithelial-mesenchymale Transition im juvenilen Angiofibrom

Objective: Juvenile angiofibroma (JA) is an intriguing fibrovascular neoplasm that has prompted diverse theories of origin since 1853. While approaches focusing on isolated features of JA have not gained broad acceptance, the current explanation of JA tumorigenesis based on embryologic vascular remnants is gaining prominence. In the core embryologic process of epithelial-mesenchymal transition (EMT), the transcription factors Twist1 and Snail/Slug play key roles; their expression in JA is therefore of particular interest within this embryologic framework. Material and methods: In a cohort of 19 JAs, quantitative real-time PCR (qRT-PCR) analyses and immunohistochemical investigations were performed for the transcription factors Twist1 and Snail/Slug, as well as for CD31 (Pecam1) and vimentin. Results: Twist1 and Snail2 were detectable by RT-PCR in all JAs examined (n=11). No correlation was observed with vessel-rich (CD31-positive) or fibrous (vimentin-positive) tumor regions. Immunohistochemistry for Twist1 and Snail/Sslug confirmed protein-level expression (n=19), with inter- and intratumoral heterogeneity of EMT markers. Conclusions: Demonstration of Twist1 and Snail/Slug expression in JA indicates involvement of the embryologic process of EMT in JA and supports the embryologic explanatory model, which accounts for the clinical characteristics of this unique fibrovascular neoplasm.