MYBL1 and adenoid cystic breast carcinoma: For example, adenoid cystic carcinomas of the breast are primarily driven by the MYB-NFIB fusion gene in ~80% of cases43,44; in breast adenoid cystic carcinomas lacking these fusions, MYBL1 rearrangements and MYB gene amplification have been reported as alternative mechanisms resulting in MYB overexpression and activation of MYB targets45.