Laminin expression in juvenile angiofibroma indicates vessel's early developmental stage

This study confirms the wide range of vascular architecture in juvenile angiofibromas. Proof of laminin alpha2 expression in tumour vessels is suggested to indicate presence of vessels of early developmental stage in juvenile angiofibromas, supporting the concept that plexus remnants of the first branchial arch artery contribute to the vascular tumour component.

Laminins, one of the major components of vascular wall basement membranes, have been implicated in tumour growth and have been shown to have developmentally regulated expression patterns. The goal of this study was to analyse the expression of laminins in juvenile angiofibromas.

A detailed analysis of the laminin isoform expression was performed by immunofluorescence staining for laminin chains alpha1, alpha2, alpha3, alpha4, alpha5, beta1, beta2, beta3, gamma1, gamma2, and gamma3 on cryosections of 10 juvenile angiofibromas and inferior nasal turbinate tissue for control.

Vascular staining of the different laminin chains revealed areas of differential vessel density in juvenile angiofibromas and irregularities in vessel size, configuration and architecture. Similar to vessels in nasal turbinates, laminins alpha4, alpha5, beta1, beta2 and gamma1 were found to be expressed in juvenile angiofibroma vessels. In contrast to vessels of nasal turbinates, staining for alpha2 and alpha3 chains was only detected in vessels of juvenile angiofibromas.