抄録
Although the status of surgical margins and regional lymph node metastases are relevant prognostic factors in oral squamous cell carcinoma （OSCC）, local recurrences, distant metastases （r/m）, or both have occurred in a subset of OSCC patients with histologically negative margins/lymph nodes.The principle objective of our study was to assess the possible monitoring of such OSCC cases by quantitative real-time PCR combined with high-resolution melting curve analysis （qPCR-HRMA） for circulating free mitochondrial DNA （mtDNA）, which has copy numbers hundreds to thousands times higher than those of genomic DNA （gDNA） in each cell. mtDNA from normal and tumorous tissues and serum mtDNA obtained at two time points （pre-surgery, and 4 weeks post-surgery） from 43 patients （34 r/m-negative cases and 9 r/m-positive cases） were examined for the D-loop region at position 68 of human mtDNA genome. On qPCR-HRMA, we found that mutant mtDNA was identified in the samples from tumorous tissues at much higher concentrations than in samples from corresponding normal tissues. Furthermore, 67 ％ of r/m-positive cases showed higher amounts of mtDNA （＞50 ％） in their tumor tissues as compared with the r/m-negative group. On blood tests, all serum mtDNA samples obtained 4 weeks after surgery in r/m-positive cases, except for one case, maintained high amounts of mutant mtDNA.In conclusion, tumor-specific mitochondrial mutations in the sera of OSCC patients can be successfully identified using qPCR-HRMA, and this technique has potential application for the surveillance of patients after tumor resection.
