Molecular detection of occult cancer cells in human lung cancer

肿瘤细胞从原发部位分离并释放到循环中是转移级联反应的早期事件之一。尽管循环肿瘤细胞的存在并不一定与随后出现的系统性疾病相关，但一些这样的肿瘤细胞可能具有建立转移的潜力，因此可能会对患者的预后产生负面影响。由于循环细胞的数量可能很少，因此它们的检测方法需要既敏感又特异。形态学、流式细胞术、常规细胞遗传学和免疫细胞化学已被用于检测循环肿瘤细胞。然而，这些技术相对不敏感，依赖于抗体与肿瘤相关细胞表面抗原的相互作用。如果抗体与正常抗原发生交叉反应，或者如果肿瘤抗原存在于宿主免疫细胞上，这些方法可能会产生假阳性结果。分子…的最新进展更大的技术，包括聚合酶链式反应(PCR)的出现，使得灵敏地检测外周血中循环中的肿瘤细胞成为可能。一些研究人员使用癌胚抗原(CEA)作为靶基因，因为几乎所有的上皮细胞都可以检测到CEA mRNA，包括癌细胞，但在非上皮细胞中检测不到。逆转录聚合酶链式反应(RT-PCR)扩增CEA基因是检测外周血中循环癌细胞的有效方法。如果在血液样本中检测到CEA mRNA，这意味着异位上皮细胞的存在，因此可能是癌细胞。CEA信使核糖核酸阳性患者的生存率明显低于CEA信使核糖核酸阴性患者，其中术后CEA信使核糖核酸阳性患者的生存率最低。肺癌根治性手术患者术前外周血CEA mRNA的分子检测是一个独立的预后因素。较少

The detachment of tumor cells from the primary site and the release of them into the circulation is one of the early events in the metastatic cascade. Although the presence of circulating tumor cells does not necessarily correlate with the subsequent appearance of systemic disease, some such tumor cells may have the potential to establish metastases and so may have a negative influence on patient prognosis. Since the number of circulating cells may be very small, methods for their detection need to be both sensitive and specific. Morphology, flow cytometry, conventional cytogenetics, and immunocytochemistry have been used to detect circulating tumor cells. However, these techniques are relatively insensitive and dependent upon the interaction of antibodies with tumor-associated cell-surface antigens. These methods may yield false-positive results if the antibodies cross-react with normal antigens or if the tumor antigens are presented on host immune cells. Recent developments in molecu … More lar technology including the advent of the polymerase chain reaction (PCR) have permitted the sensitive detection of circulating tumor cells in the peripheral blood. Several researchers have used carcinoembryonic antigen (CEA) as the target gene because CEA mRNA can be detected in almost all epithelial cells, including cancer cells, but not in non-epithelial cells. The reverse transcriptase-polymerase chain reaction (RT-PCR) amplification method for CEA mRNA is an efficient means of detecting circulating cancer cells in the peripheral blood. If CEA mRNA is detected in blood samples, this implies the presence of ectopic epithelial cells, and hence presumably cancer cells. Patients with positive CEA mRNA in the preoperative blood samples had a poor survival when compared to those with negative CEA mRNA ; of these patients, the worst survival rate was seen in those with positive CEA mRNA in the postoperative blood samples. The molecular detection of CEA mRNA in the preoperative peripheral blood is an independent prognostic factor in patients with lung cancer who undergo a curative surgery. Less