Börmer O P
Central Laboratory, Norwegian Radium Hospital, Oslo.
Clin Chem. 1991 Oct;37(10 Pt 1):1736-9.
Four "sandwich"-type immunoassays of carcinoembryonic antigen (CEA) based on the use of monoclonal antibodies (Abbott CEA-RIA Monoclonal, Pharmacia/Wallac Delfia CEA kit, Roche CEA EIA Duomab 60, and our in-house immunoradiometric assay) were tested for cross-reaction with nonspecific cross-reacting antigen 2 (NCA-2) in meconium. The Roche assay did not react with NCA-2, but the other three assays cross-reacted strongly and to about the same extent with this antigen. NCA-2 is the CEA gene family member that is structurally most similar to CEA, and other authors have found by indirect evidence that this antigen also is increased in the serum of many cancer patients. In a previous study we found that the Roche assay yielded lower mean values than the other assays for CEA in serum from colorectal cancer patients. Furthermore, the correlation between the Roche CEA values and those of each of the other three assays was weaker than the correlation between these NCA-2 cross-reactive assays. We conclude that these results can be explained by the different cross-reactivity with NCA-2 of the antibodies used by the various assays, as described here. Our findings raise interesting questions regarding the possible role of NCA-2 as a tumor marker.
对四种基于单克隆抗体的癌胚抗原（CEA）“夹心”型免疫测定法（雅培CEA - RIA单克隆法、法玛西亚/瓦里安德尔福CEA试剂盒、罗氏CEA酶免疫分析Duomab 60以及我们内部的免疫放射分析）进行了检测，以确定它们与胎粪中无特异性交叉反应抗原2（NCA - 2）的交叉反应情况。罗氏测定法与NCA - 2不发生反应，但其他三种测定法与该抗原发生强烈交叉反应，且程度大致相同。NCA - 2是CEA基因家族中在结构上与CEA最相似的成员，其他作者通过间接证据发现，该抗原在许多癌症患者的血清中也会升高。在先前的一项研究中，我们发现对于结直肠癌患者血清中的CEA，罗氏测定法得出的平均值低于其他测定法。此外，罗氏CEA值与其他三种测定法中每一种的相关性，都弱于这些与NCA - 2交叉反应的测定法之间的相关性。我们得出结论，如本文所述，这些结果可以通过各种测定法所使用抗体与NCA - 2的不同交叉反应性来解释。我们的发现引发了关于NCA - 2作为肿瘤标志物可能作用的有趣问题。
