临床上根据转移瘤和原发瘤形态结构近似的这一生物学特性对诊断转移瘤十分有帮助,通常采用免疫组织化学技术显示特殊成分 CK 及其单克隆抗体以识别上皮性肿瘤.近年来,一些学者应用靶向 CK20 mRNA 的逆转录多聚酶链反应(RT-PCR)方法检测结直肠癌患者外周血中的肿瘤细胞.我们采用巢式逆转录多聚酶链反应(RT-PCR)方法,以 CK20 mRNA为靶基因,检测32例大肠癌患者外周血中 CK20 mRNA 表达,CK20 mRNA 阳性表达可作为癌细胞血行播散的临床指标,结果如下.1 材料和方法1.1 材料大肠癌患者32例均为本院普外科住院病例,男19例,女13例.年龄27岁～74岁,平均55.7岁.32例均行手术治疗,其中大肠癌根治术21例,非根治性切除术组11例(姑息性切除术者8例,剖腹探查者3例),均经病理组织学证实.癌细胞分化程度:高分化者3例,中分化者17例,低分化者12例.Dukes 分期:A 期12例,B 期6例,C 期7例,D 期7例.有淋巴结转移者13例(40.6%),有远处转移者7例(21.8%).治愈出院者27例(84.4%),病情无明显变化者5例(15.6%).对照组10例(直肠息肉3例,胆囊结石3例,其他4例),分别于术前、术后48 h,7 d～14 d 抽取患者的外周血标本,采用 RT-PCR 法检测.另外还检测了3例原发性肝细胞肝癌患者外周血标本.1.2 方法从外周静脉中抽取血液4mL,置于肝素化的试管内立即混匀送实验室.有核细胞的制备采用密度梯度离心法.提取细胞总 RNA,采用 Trizal 抽提法.合成 cDNA,应用 Gibco Clinically, according to the biological characteristics of metastasis and primary tumor morphology similar to the structure of the diagnosis of metastases is very helpful, usually using immunohistochemical techniques to display specific components of CK and its monoclonal antibody to identify epithelial tumors.In recent years, Some scholars use the reverse transcription polymerase chain reaction (RT-PCR) method targeting CK20 mRNA to detect the tumor cells in the peripheral blood of patients with colorectal cancer.We used nested reverse transcription polymerase chain reaction (RT-PCR) method to CK20 mRNA As the target gene, detection of 32 cases of colorectal cancer patients with CK20 mRNA expression in peripheral blood, CK20 mRNA expression can be used as a clinical indicator of hematogenous dissemination of cancer cells, the results are as follows.1 Materials and methods 1.1 Materials 32 cases of colorectal cancer patients were hospital General surgical inpatients, 19 males and 13 females, aged 27 years to 74 years, mean 55.7 years old .32 cases were undergone surgical treatment, including 21 cases of colorectal cancer radical surgery, 11 cases of non-radical resection group (palliative 8 cases of resection, 3 cases of laparotomy) were confirmed by histopathology.The differentiation degree of cancer cells: 3 cases of well-differentiated, 17 cases of moderately differentiated and 12 cases of poorly differentiated.Dukes staging: 12 cases of stage A , 6 cases in stage B, 7 cases in stage C and 7 cases in stage D There were 13 cases (40.6%) with lymph node metastasis, 7 cases (21.8%) with distant metastasis, 27 cases (84.4%) discharged cured, 5 cases (15.6%) with no obvious change, and 10 cases (3 cases of rectal polyps, 3 cases of gallstones and 4 cases of the other), the peripheral blood samples of patients were collected preoperatively, 48 h and 7 d ~ 14 d after operation, and RT- Cases of primary hepatocellular carcinoma patients with peripheral blood samples .1.2 Methods Blood from the peripheral venous withdrawal 4mL, placed in the heparinized tube immediately mix and sent to the laboratory. Preparation of nucleated cells using density gradient centrifugation. Total cell extraction RNA using Trizal extraction cDNA synthesis using Gibco