胃肠恶性肿瘤外周血微转移的检测及其临床意义

Significance of detecting disseminated tumor cells in peripheral blood of gastric and colorectal cancer patients

目的研究胃癌、大肠癌患者外周血CK20 mRNA的表达,并探讨其临床意义。方法采用RT-PCR方法检测47例胃癌患者、58例大肠癌患者和6例非恶性病手术志愿者骨髓、门静脉和外周血CK20 mRNA的表达,并随访1年。结果6例健康志愿者无CK20 mRNA阳性表达;47例胃癌患者骨髓、门静脉血CK20 mRNA阳性表达率分别为87.2％(41/47)和85.1％(40/47);58例大肠癌患者骨髓、门静脉血阳性表达率分别为77.6％(45/58)和74.1％(43/58)。单次外周血采样CK20 mRNA阳性表达率胃癌患者为42.6％(20/47),大肠癌患者为44.8％(26/58);两次采样总阳性率胃癌患者为74.5％(35/47),大肠癌患者为69.0％(40/58)。外周血总阳性率略低于骨髓和门静脉血(P>0.05),外周血重复采样阳性率高于单次采样(P<0.05)。Duke C期患者CK20 mRNA阳性表达率高于DukeA、B期(P<0.05)。1年局部或远处复发率CK20 mRNA外周血阳性表达患者高于阴性者(P<0.05)。结论胃肠癌患者外周血CK20 mRNA RT-PCR检测有与骨髓、门静脉血相似的敏感性和特异性,可以作为检测胃肠癌微转移的指标并指导其治疗和预后。

Objective To evaluate the clinical significance of CK20 mRNA expression in detecting disseminated tumor cells in peripheral blood of gastric and colorectal cancer patients. Methods Expression of CK20 mRNA was investigated by RT-PCR in bone marrow, portal vein and peripheral blood in 47 gastric, 58 colorectal cancer patients and 6 non-cancer volunteers. All the patients were followed-up for one year. Results There was no positive expression of CK20 mRNA in 6 non-cancer volunteers. The positive rates of CK20 mRNA in bone marrow, portal vein were 87.2%(41/47) and 85. l%(40/47)in gastric cancer, and were 77.6%(45/58) and 74.1% (43/58)in colorectal cancer. The positive rates of CK20 mRNA in peripheral blood in gastric and colorectal cancer patients were 42.6 % (20/47) and 44.8 % (26/58) by one single test, and were 74.5 % (35/47) and 69.0%(40/58)by two tests. The overall positive rate of CK20 mRNA in peripheral blood (two tests) was similar to that in bone marrow and portal vein. The overall positive rate of CK20 mRNA in peripheral blood was higher in two tests than in one single test ( P < 0.05) and in advanced than early leisions. The relapse rate within one year was higher in CK20 mRNA positive patients than the negative ones( P < 0.05 ) . Conclusion Detection of cancer cells by RT-PCR for CK20 mRNA in peripheral blood, being as sensitive and specific as in bone marrow and portal vein, is reliable and convenient in diagnosing micrometastasis of gastric and colorectal cancer, which possesses clinical significance in assessing the prognosis and scheme of therapy.