Comparative genomic hybridization of frozen salivary or pulmonary adenoid cystic carcinoma samples and normal tissue to identify copy number alterations

Adenoid cystic carcinoma (AAC) is a rare but distinctive tumor. Array comparative genomic hybridization (CGH) has been applied for detecting chromosomal copy number alterations in seventeen frozen salivary or pulmonary ACCs samples. There were recurrent gains at 1p36, 6p21, 16q24, 17q21, and 22q11-13, and recurrent losses at 1p35, 6q22, 8q12-13, 9p21, 12q12-13, and 17p11-13. The minimal common regions (MCRs) of these alterations contained several well-known cancer genes, including TP53, CDKN2A/CDKN2B, SKI, CDK10, and VEGF. CDK10 was the only oncogene that localized to the MCR of gain at 16q24.1-24.3. In addition, we identified LIMA1 as the sole putative tumor suppressor gene residing in the MCR of deletion at 12q12q12-13.2. Among well defined and narrow, but unique alterations, there were gains harboring MDM2, cyclin D1, and KIT, as well as one loss involving the hsa-mir-124a-2 miRNA. Using immunohistochemistry, we found abnormal protein expression in the cases with gain of cyclin D1 or MDM2. In conclusion, the majority of previously reported chromosomal copy number alterations are found using array CGH in this small cohort. The suspicion that genes such as TP53, CDKN2A/CDKN2B, and VEGF might play a role in ACC, is strengthened by our results. CDK10 and LIMA1 emerge from our analysis as candidate cancer genes