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

建立了利用RT-PCR检测基质溶素（MTR）检测结直肠癌局部淋巴结微转移的系统。MTR方法可以在一个淋巴结中检测到小到10^4个癌细胞。MTR方法的灵敏度明显高于H-E染色的常规组织病理学检查。常规法阴性、MTR法阳性的病例中，约60%的病例通过后续连续切片变为H-E染色阳性，而两种方法均阴性的病例均未在同一次检查中变为阳性。此外，MTR方法对点突变k-ras微转移的敏感性显著高于其他著名的分子生物学方法。对常规方法检测为阴性、MTR检测为阳性且未复发的病例进行预后观察。我科对结直肠癌患者行根治性淋巴结清扫，局部复发或区域淋巴结复发率明显低于其他设施。另一个问题是由于PCR的超高灵敏度导致假阳性。然后我们正在尝试使用TaqMan PCR方法对母体溶素进行定量PCR。要建立这种新技术，还需要进一步的研究。

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.