Gene expression profiles in lymph nodes with metastasis of oral squamous cell carcinoma (OSCC)

Background: Cervical lymph node metastasis is a potent prognostic factor in oral squamous cell carcinoma (OSCC). However, lymph nodes resected by sentinel node biopsy or neck dissection are usually diagnosed by examining only one or two sections of the maximal cut surface. Accurate diagnosis of the metastasis in lymph nodes is important but depends on a heavy workload of the pathologist. In this study, we have attempted to identify novel molecular markers to find the harboring cancer cells in the lymph node and establish rapid detection method. Methods: We determined the gene expression profiles of 7 metastatic lymph nodes from patients with OSCC and 1 normal lymph node and 5 salivary glands from non-cancerous patients by microarray analysis. We found the overexpression genes in all metastatic lymph nodes. Subsequently, we examined the expression of these genes in newly 23 metastatic lymph nodes and 9 normal lymph nodes by real-time quantitative RT-PCR (qRT-PCR) assay. Moreover, the rapid detection of lymph node metastasis by these genes was examined using the reverse transcription loop-mediated isothermal amplification (RT-LAMP) method. Result: Among the 4 genes identified by microarray analysis, annexin A8 (ANXA8) and desmoglein 3 (DSG3) were detected in all metastatic lymph nodes at a much higher level but not in normal lymph nodes at all by qRT-PCR. Furthermore, RT-LAMP method targeting ANXA8 rapidly detected almost lymph nodes with metastasis. Conclusions: ANXA8 could be a useful marker for detecting lymph node metastasis in OSCC.