Fusion oncogenes in adenoid cystic carcinoma

Abstract

Abstract Purpose Adenoid cystic carcinomas of the salivary glands have a consistent t(6;9)(q22‐23;p23‐24) translocation. A recent study have shown that this results in fusion of the transcription factor gene MYB and the transcription factor gene NFIB which leads to activation of critical MYB target genes. The purpose of the study was to determine the expression of the MYB‐NFIB fusion in lacrimal gland adenoid cystic carcinomas. Methods Primary lacrimal gland adenoid cystic carcinomas in Denmark during 1974‐2007 were collected and classified according to the latest WHO classification system. The formalin‐fixed paraffin‐embedded tumours were analyzed using RT‐PCR for detection of MYB‐NFIB fusion transcript. 10 other non‐adenoid cystic carcinomas of the lacrimal gland were also tested for the fusion. Results A total of 13 patients with a primary adenoid cystic carcinoma were identified in Denmark during the 33‐year period. The median age at diagnosis was 41 years and the gender distribution was equal. Using RT‐PCR the fusion transcript could be detected in five (38%) of the 13 cases. The fusion was the transcript variant MYB exon 14 linked to NFIB exon 8c in all five cases. None of the non‐adenoid cystic carcinoma cases expressed the MYB‐NFIB fusion. Conclusion The MYB‐NFIB fusion is expressed in adenoid cystic carcinomas of the lacrimal gland. The result of the study supports the suggestion that the MYB‐NFIB fusion is specific for adenoid cystic carcinoma. This is the first study to evaluate the frequency of the MYB‐NFIB fusion in adenoid cystic carcinomas in the lacrimal gland.