Molecular genetic studies on EGFR, KRAS, BRAF, ALK, PIK3CA, PDGFRA, and DDR2 in primary pulmonary adenoid cystic carcinoma

Background: Pulmonary adenoid cystic carcinoma (PACC) is an uncommon neoplasm of the lung but represents the predominant type of salivary gland-type lung carcinoma. Only a few studies have focused on the genetic events associated with PACC. The aim of this study was to characterize the genetic events associated with PACC. Findings: We reviewed 24 cases of primary PACC between 2000 and 2014, including 21 cases reported in our previous study and three new cases added in 2014. Mutation profiling of the EGFR, KRAS, BRAF, ALK, PIK3CA, PDGFRA, and DDR2 genes was performed using next-generation sequencing, Sanger sequencing, and quantitative polymerase chain reaction in 9 successfully amplified cases. The 24 cases of PACC included 7 men and 17 women, aged 24-74 years (mean, 50.8 years). All the cases were located in the trachea or bronchus. No mutations were detected in any of the seven genes in the nine cases that qualified for mutation analysis, and the results using different methods were consistent. Conclusions: The data presented in this work suggest that EGFR, KRAS, BRAF, ALK, PIK3CA, PDGFRA, and DDR2 may not be driver genes in primary pulmonary adenoid cystic carcinoma.