Challenges in enumeration of CTCs in breast cancer using techniques independent of cytokeratin expression

IntroductionGiven the current postulated plasticity between epithelial and mesenchymal states of migratory cancer cells the detection of non-epithelial CTCs is an important scientific and clinical goal.MethodsWe used the filtration-based ISET technology to enrich circulating tumour cells (CTCs) in early breast cancer blood samples and identify them using a morphology-based immunocytochemistry (ICC) approach.ResultsWe found greater numbers of putative CTCs by this approach than by the cytokeratin-based CellSearch technology, but a high number of CTC false positives were identified in healthy volunteer samples which were not reduced in successive blood draws. Preliminary work using an oestrogen receptor (ER)-based multiplex ICC method in metastatic breast cancer ISET samples indicated a low number of ER+ CTCs even at this advanced stage.ConclusionsThis work highlights the challenges in enumerating CTCs without conventional epithelial markers.引言 鉴于当前学界提出的迁移性癌细胞上皮与间质状态间的可塑性，检测非上皮性循环肿瘤细胞（circulating tumour cells, CTCs）是一项重要的科学与临床研究目标。 方法 本研究采用基于过滤的ISET技术，对早期乳腺癌患者血液样本中的循环肿瘤细胞（circulating tumour cells, CTCs）进行富集，并通过基于形态学的免疫细胞化学（immunocytochemistry, ICC）方法完成鉴定。 结果 相较于基于细胞角蛋白的CellSearch技术，本方法检出的疑似循环肿瘤细胞数量更多；但在健康志愿者的血液样本中检测到大量循环肿瘤细胞假阳性，且连续采血样本的假阳性数量未出现下降。在转移性乳腺癌的ISET样本中，采用基于雌激素受体（oestrogen receptor, ER）的多重免疫细胞化学方法开展的初步研究显示，即便处于该晚期阶段，雌激素受体阳性（ER+）循环肿瘤细胞的数量仍处于较低水平。 结论 本研究凸显了在不使用常规上皮标志物的前提下对循环肿瘤细胞进行计数所面临的挑战。