Brn-3a and Brn-3b are differentially expressed in recurrent respiratory papillomatosis associated to HPV-6 and HPV-11 infection

Abstract

Brn-3a and Brn-3b are transcription factors expressed mainly in somatosensory neurons during embryonic stage; but they are absent in adulthood. Both share the same DNA binding site with an antagonist effect. Brn-3a expression has been reported 300 fold increased in Cervical Intraepithelial Neoplasia grade 3 (CIN3) compared with normal cervix tissue; some studies suggest that Brn-3a may increase the expression of HPV onco-proteins E6 and E7 by interaction with the promoter region of some high risk HPV genotypes. In this study, we analyzed the expression of Brn-3a and Brn-3b in laryngeal tissue biopsies from patients with Recurrent Respiratory Papillomatosis (RRP) and in volunteers´ health tissue. HPV was detected in all RRP samples and only HPV-6 and HPV-11 were detected in the samples of RRP. Brn-3a was expressed in 87% of the samples and Brn-3b in 45% co-expressed with Brn-3a. Brn-3a is expressed in laryngeal papillomas of patients with RRP diagnostic; but not in normal laryngeal tissue. The most of the samples expresses Brn-3a and only half weakly expresses Brn-3b; which suggests that the antagonist role of Brn-3b over Brn-3a is absent in this process.