口腔癌の微小転移に関する遺伝子診断

抄録

The 5-year survival rate of patients with oral cancer has improved, due to the development of treatment modalities combined with surgery and chemoradio-immunotherapy. Although various biomarkers have been studied for their value as prognostic factors, nodal status (N status) and distant metastasis (M status). are still the significant prognostic factors of oral cancer. Therefore, early detection of micrometastases (MMs) in the cervical lymph nodes (LNs) is expected to further improve survival. This article describes detailed content of an assigned presentation at the 54th Annual Meeting of the Japanese Stomatological Society. MMs, defined as foci < 3 mm in size, were detected in 29 sites of 23 lymph nodes (4.2%) in 21.9% of 73 patients examined by semiserial sectioning. Conventional RT-PCR supported that keratin (K) 13 is a suitable epithelial marker for detecting MMs in cervical LNs. However, its illegitimate gene expression was detected by TaqMan PCR. SCC antigen mRNA is proved to be a superior tumor marker for TaqMan PCR. A mutant alle-specific amplification method showed high sensitiviy and specificity, even though the method is limited to the case with genetic alteration.
Further, an animal model with GFP-transfected cancer cells, and genetic analysis using a high throughput DNA chip were introduced.
The following conclusions were obtained. First, genetic diagnosis is more sensitive and faster than morphologic detection. Second, SCCA mRNA may be a promising marker for detecting occult metastases. Third, TaqMan PCR serves for relative quantity. Fourth, gN grading will be available in the future.