Primary adenoid cystic carcinoma of the lung: Absence of KIT mutations

BACKGROUND. Primary pulmonary adenoid cystic carcinomas (ACCs) are rare lung neoplasms that are challenging to completely resect and can exhibit poor survival. Adjuvant therapy is often ineffective and identification of a targeted novel therapy would be useful. The objective of the current study was to evaluate KIT expression and KIT-activating mutations. METHODS. Primary salivary gland-type tumors of the lung diagnosed between 1972 and 2002 at the Mayo Clinic were identified and the subset of primary pulmonary ACCs were reviewed. Immunohistochemical study for KIT expression and KIT gene mutations in exons 9, 11, 13, and 17 were performed on paraffin-embedded tissue. RESULTS. Forty-nine patients were diagnosed with primary pulmonary ACC. The majority of ACC cases were predominantly the cribriform type (74.4%). KIT immunoreactivity was evaluated in 34 cases and was found to be present in all but 1 case (97%). No mutations were detected in KIT gene exons 9, 11, 13, and 17 in a subset of 12 cases. CONCLUSIONS. Although KIT expression was found frequently in primary pulmonary ACC, a correlation with KIT-activating mutations was not observed.