The tumor is characterized by a relatively stable genome and indolent and progressive clinical behavior. Significant number of ACC manifest t(6;9) translocation, which may lead to fusions of the MYB-NFIB genes. We identified a different gene fusion involving MYB/PDCD1LG2 in an ACC with t(6:9).

Adenoid cystic carcinoma (ACC) is second most common malignancy of human salivary glands. ACC is slow progressing malignancy with a lethal outcome. The primary treatment for patients with ACC is surgical resection with and without post-operative radiotherapy. Patients with recurrent and distant metastatic disease have limited therapeutic options.

Histopathologically, ACC manifests three distinctive morphologic patterns that include cribriform, tubular and solid forms. The organization of the tubular and cribiform patterns is attributed to the presence of myoepithelial cells while the evolution of the solid form is coincident with the loss of these cells.

t(6;9)(q23;p24) translocation results in a fusion transcript consisting of MYB and NFIB 6 the most common finding. A novel fusion between the MYB gene and the PDCD1LG2 gene was recently identified in an ACC (Mitani et al., 2010; Mitani et al., 2011).

MYB (v-myb myeloblastosis viral oncogene homolog (avian))

6q23.3

The nucleotide sequences and genomic organization of MYB (accession number NM_001130173) was obtained from the National Center for Biotechnology Information (NCBI; http://www.ncbi.nlm.nih.gov)

PDCD1LG2 (programmed cell death 1 ligand 2)

9p24.1

The nucleotide sequences and genomic organization of PDCD1LG2 (accession number NM_025239) was obtained from the National Center for Biotechnology Information (NCBI; http://www.ncbi.nlm.nih.gov)

Inverted intron 3 of PDCD1LG2 gene was fused with MYB gene on exon 15. One of 102 patients with ACC was identified this fusion by 3RACE technique.

3RACE was performed to identify the unknown gene fusion of MYB and described by Mitani Y et al., 2010.

No evidence for fusion protein is documented.
Anti-MYB antibody recognized N-terminal of MYB confirmed the presence of truncated MYB protein by western blotting. The tumor is MYB positive by immunohistochemical analysis using the same anti-MyB anti-body.