Recurrent fusion of MYB and NFIB transcription factor genes in carcinomas of the breast and head and neck

• The transcription factor gene MYB was identified recently as an oncogene that is rearranged/duplicated in some human leukemias. Here we describe a new mechanism of activation of MYB in human cancer involving gene fusion. We show that the t(6;9)(q22-23;p23-24) translocation in adenoid cystic carcinomas (ACC) of the breast and head and neck consistently results in fusions encoding chimeric transcripts predominantly consisting of MYB exon 14 linked to the last coding exon(s) of NFIB. The minimal common part of MYB deleted as the result of fusion was exon 15 including the 3'-UTR, which contains several highly conserved target sites for miR-15a/16 and miR-150 microRNAs. These microRNAs recently were shown to regulate MYB expression negatively. We suggest that deletion of these target sites may disrupt repression of MYB leading to overexpression of MYB-NFIB transcripts and protein and to activation of critical MYB targets, including genes associated with apoptosis, cell cycle control, cell growth/angiogenesis, and cell adhesion. Forced overexpression of miR-15a/16 and miR-150 in primary fusion-positive ACC cells did not significantly alter the expression of MYB as compared with leukemic cells with MYB activation/duplication. Our data indicate that the MYB-NFIB fusion is a hallmark of ACC and that deregulation of the expression of MYB and its target genes is a key oncogenic event in the pathogenesis of ACC. Our findings also suggest that the gain-of-function activity resulting from the MYB-NFIB fusion is a candidate therapeutic target.

Ämnesord

MEDICIN OCH HÄLSOVETENSKAP  -- Medicinska och farmaceutiska grundvetenskaper -- Cell- och molekylärbiologi (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Basic Medicine -- Cell and Molecular Biology (hsv//eng)

Nyckelord

Adult

Aged

Base Sequence

Breast Neoplasms/*genetics/*pathology

Carcinoma

Adenoid Cystic/*genetics/*pathology

Chromosomes

Human

Pair 6/genetics

Chromosomes

Human

Pair 8/genetics

Female

Gene Expression Regulation

Neoplastic

Head and Neck Neoplasms/*genetics/*pathology

Humans

Leukemia-Lymphoma

Adult T-Cell/genetics

Male

MicroRNAs/genetics

Middle Aged

Molecular Sequence Data

Oncogene Proteins

Fusion/genetics/*metabolism

RNA

Messenger/genetics/metabolism

Translocation

Genetic

Publikations- och innehållstyp

ref (ämneskategori)

art (ämneskategori)