Establishment of detection system of micrometastasis in the regional lymph nodes of colorectal cancer by RT-PCR for matrilysin

建立了基质溶解素（MTR）RT-PCR检测结直肠癌区域淋巴结微转移的方法。MTR方法可以在一个淋巴结中检测到小至10^4个癌细胞。MTR法的敏感性明显高于常规组织病理学检查H-E染色法。常规法阴性、MTR法阳性的病例中，约60%经连续切片后转为H-E染色阳性，但两种方法均阴性的病例在同一次检查中无一例转为阳性。MTR法检测K-ras点突变的敏感性明显高于PCR法检测微转移的敏感性。我们正在密切关注常规方法显示为n 0和MTR方法显示为阳性的病例的预后，这些病例中没有发现复发。我科对结直肠癌患者行根治性淋巴结清扫术，局部复发或区域淋巴结复发率明显低于其他机构。另一个问题是由于PCR的超高灵敏度而导致的假阳性。我们现在尝试用TaqMan PCR方法对matrilysin进行定量PCR。为了建立这种新技术，需要进一步的检查。

Detection system of micrometastasis in the regional lymph nodes of colorectal cancer utilizing RT-PCR for matrilysin (MTR) was established. MTR method could detect as small as 10^4 cancer cells in one lymph node. Sensitivity of MTR method was significantly higher than conventional histopathologic examination using H-E staining. About 60 % of cases showing conventional method negative, and MTR method positive, changed into H-E staining positive by additional sequential sectioning, however, no cases showing negative in the both methods changed into positive in the same examination. Moreover, MTR method was significantly sensitive than the other famous molecular biological method detecting micrometastasis using PCR for point mutated k-ras. We are keeping watch on prognosis of cases showing n0 by conventional method and positive by MTR method and no recurrence has been detected in those cases. In our department, radical lymph node dissection was performed for patients of colorectal cancer, then local recurrence or recurrence of regional lymph nodes was signifcantly less than the other facilities. The other problem is false positive of PCR because of its super-high sensitivity. Then we are now trying to perform quantitative PCR using TaqMan PCR method for matrilysin. To establish this new technique, further examination is necessary.