Abstract 4604: Some of oral squamous cell carcinomas might originate from minor salivary glands, and these tumors shows aggressive biological behavior and poor prognosis

Abstract

Abstract Oral cancer massively invades the adjacent tissues and frequently metastasizes to the regional lymph nodes. Most of the oral cancer is histopathologically squamous cell carcinoma, and approximately 10 % of the oral floor cancer is salivary gland cancer, such as mucoepidermoid carcinoma and adenoid cystic carcinoma. According to the clinical behavior and histopathological features of the oral squamous cell carcinoma (OSCC), we hypothesize that OSCC might originate from either oral squamous epithelium or minor salivary glands. In this study, we attempted to clarify the possibility, in which some of the OSCC originated from minor salivary glands by microarray and clustering analysis. Furthermore, by using the eleven molecular markers which were identified by the microarray and clustering analysis, we determined the origin of OSCC, and compared their biological aggressiveness in the patients. The mRNA expression profile of the samples obtained from 6 patients with OSCC was analyzed by the AB1700 Chemiluminescent Microarray Analyzer on the Human Genome Survey Array containing 29,098 genes. Clustering analysis was performed by GeneSping GX 7.3. Clustering analysis by the expression level of the 917 genes, which were differentially expressed at least 3-folds in normal oral squamous epithelium and normal salivary glands, revealed that 6 samples can be divided into 2 groups. The expression profile of one group (4 cases) was similar to that of normal oral squamous epithelium, and that of another group (2 cases) was similar to that of normal salivary glands. Furthermore, we identified 11 genes from the 917 genes which can easily determine the origin of the OSCC. Subsequently, we examined the expression levels of 9 marker genes in 73 OSCC (45 men, 28 women) by RT-PCR and determined the origin of the OSCC. Twelve cases from 73 OSCCs (16%) were considered to originate from minor salivary glands, and these tumors showed highly metastatic potentials and poor prognosis. In conclusion, OSCC originates from either oral squamous epithelium or minor salivary glands. OSCCs originating from minor salivary glands showed aggressive biological behavior. Determination of the origin of the OSCC is helpful to make a treatment plan for the patients with OSCC. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 4604. doi:1538-7445.AM2012-4604