Different correlations between tumor size and cancer-related gene profiles according to histologic type of salivary gland tumor.

Salivary gland tumors are mostly benign, and malignant tumors are rare. Because of this rarity, there is little molecular biology research on salivary gland tumors. Recently, we have published an analysis of the telomere length (TL) in salivary gland tumors. In this paper, we analyzed amplification of the catalytic subunit of phosphatidylinositol 3-kinase (PIK3CA) and mitochondrial DNA copy number (mtCN) in salivary gland tumors. To investigate mutations in PIK3CA, we performed genomic sequencing on samples of salivary gland tumors extracted from patients. The expression level of PIK3CA mRNA and mtCN were measured by RT-PCR. PIK3CA amplification and mtCN did not differ between Warthin's tumor (WT), pleomorphic adenoma (PA), and carcinoma of the salivary gland. The size of the tumor and the molecular profile correlated in three relationships: the size of WT with PIK3CA and with mtCN, and the size of PA with TL. We found no correlation between the size of carcinoma and the molecular profile. There was no correlation between age and molecular profile in all histologic groups of salivary gland tumor. We found no correlation between TL and mtCN in each histologic group. Although we have not found any significant results for the molecular profile of salivary gland tumors, our study can be a basis for further studies on other oncogenes in salivary gland tumors. IJCEP