Schee Kristina, Flatmark Kjersti, Holm Ruth, Boye Kjetil, Paus Elisabeth
Department of Tumor Biology, Norwegian Radium Hospital, Oslo University Hospital, 0424 Oslo, Norway.
Tumour Biol. 2012 Feb;33(1):73-83. doi: 10.1007/s13277-011-0247-5. Epub 2011 Oct 18.
Carcinoembryonic antigen (CEA) is still the only routinely used biomarker in colorectal cancer (CRC), but its utility is hampered by poor specificity and sensitivity, and the search for novel biomarkers is highly warranted. The nonspecific cross-reacting antigen 2 (NCA-2), a truncated CEA species molecule which is transcribed from the same gene, has been suggested as an alternative biomarker to CEA. In the present work, specific immunofluorometric assays were used for detection of NCA-2 and full-length CEA in bone marrow plasma from 277 CRC patients to assess their value as prognostic biomarkers, and detection was also performed in tumor tissue and a CRC cell line. Elevated plasma CEA was associated with advanced tumor stage at diagnosis and adverse patient outcome, while for NCA-2, although the same trends were observed, no additional prognostic information was gained. While specific detection of NCA-2 was clearly achieved in plasma samples, cross-reactivity with full-length CEA was observed when the antigen was exposed to common fixation chemicals. The results from this study indicate that NCA-2 is probably not a prognostic biomarker in CRC and, furthermore, underline the issue of antibody specificity when investigating CEA species molecules.
癌胚抗原（CEA）仍是目前结直肠癌（CRC）唯一常规使用的生物标志物，但其特异性和敏感性较差，限制了其应用，因此亟需寻找新型生物标志物。非特异性交叉反应抗原2（NCA-2）是一种从同一基因转录而来的截短型CEA分子，已被提议作为CEA的替代生物标志物。在本研究中，采用特异性免疫荧光测定法检测277例CRC患者骨髓血浆中的NCA-2和全长CEA，以评估其作为预后生物标志物的价值，并在肿瘤组织和一种CRC细胞系中进行检测。血浆CEA升高与诊断时的肿瘤晚期和不良患者预后相关，而对于NCA-2，虽然观察到相同趋势，但未获得额外的预后信息。虽然在血浆样本中能够明确实现NCA-2的特异性检测，但当抗原暴露于常见固定化学品时，会观察到与全长CEA的交叉反应。本研究结果表明，NCA-2可能不是CRC的预后生物标志物，此外，在研究CEA分子时强调了抗体特异性问题。
