High Specificity in Circulating Tumor Cell Identification Is Required for Accurate Evaluation of Programmed Death-Ligand 1.
High Specificity in Circulating Tumor Cell Identification Is Required for Accurate Evaluation of Programmed Death-Ligand 1.
复制标题
需要准确评估编程死亡配体1的循环肿瘤细胞鉴定中的高特异性。
DOI：
10.1371/journal.pone.0159397
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发表时间：
2016
期刊：
影响因子：
3.7
通讯作者：
Lang JM
中科院分区：
文献类型：
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作者：
Schehr JL;Schultz ZD;Warrick JW;Guckenberger DJ;Pezzi HM;Sperger JM;Heninger E;Saeed A;Leal T;Mattox K;Traynor AM;Campbell TC;Berry SM;Beebe DJ;Lang JM
程序性死亡配体1（PD-L1）在非小细胞肺癌（NSCLC）中的表达通常通过侵入性活检进行评估;然而，最近在鉴定循环肿瘤细胞（CTC）方面的进展可能是一种侵入性较小的方法，用于检测肿瘤细胞。这些液体活检依赖于从血液中的不同群体中准确识别CTC，其中一些肿瘤细胞与正常血细胞具有共同特征。虽然许多血细胞可以通过其CD 45的高表达而被排除，但中性粒细胞和其他未成熟骨髓亚群具有低至不存在的CD 45表达，并且还表达PD-L1。此外，细胞角蛋白通常用于鉴定CTC，但中性粒细胞可能对细胞内抗体（包括细胞角蛋白）进行非特异性染色，从而无法准确评估肿瘤细胞上的PD-L1表达。当在上皮细胞粘附分子（EpCAM）阳性和EpCAM阴性CTC（如上皮-间充质转化（EMT））中评价PD-L1时，这具有更大的意义。为了评价CTC错误鉴定对PD-L1评价的影响，我们利用CD 11b鉴定髓系细胞。使用EpCAM、MUC 1或波形蛋白捕获抗体和基于排除的样品制备（ESP）技术从患有转移性NSCLC的患者分离CTC。在血沉棕黄层中鉴定出大量CD 11b + CD 45 lo细胞，并对细胞内抗体（包括细胞角蛋白）进行非特异性染色。被错误识别为CTCs的CD 11b+细胞数量因患者而异;占传统识别的CTCs的33-100%。用波形蛋白捕获的细胞具有更高的CD 11b+细胞频率，为41%，而MUC 1或EpCAM分别为20%和18%。被错误鉴定为CTC的细胞最终使患者样本中的PD-L1表达发生不同程度的偏移。干扰性髓样群体可以用额外的染色标准与真正的CTC区分开，从而提高CTC鉴定的特异性和生物标志物评估的准确性。
Expression of programmed-death ligand 1 (PD-L1) in non-small cell lung cancer (NSCLC) is typically evaluated through invasive biopsies; however, recent advances in the identification of circulating tumor cells (CTCs) may be a less invasive method to assay tumor cells for these purposes. These liquid biopsies rely on accurate identification of CTCs from the diverse populations in the blood, where some tumor cells share characteristics with normal blood cells. While many blood cells can be excluded by their high expression of CD45, neutrophils and other immature myeloid subsets have low to absent expression of CD45 and also express PD-L1. Furthermore, cytokeratin is typically used to identify CTCs, but neutrophils may stain non-specifically for intracellular antibodies, including cytokeratin, thus preventing accurate evaluation of PD-L1 expression on tumor cells. This holds even greater significance when evaluating PD-L1 in epithelial cell adhesion molecule (EpCAM) positive and EpCAM negative CTCs (as in epithelial-mesenchymal transition (EMT)). To evaluate the impact of CTC misidentification on PD-L1 evaluation, we utilized CD11b to identify myeloid cells. CTCs were isolated from patients with metastatic NSCLC using EpCAM, MUC1 or Vimentin capture antibodies and exclusion-based sample preparation (ESP) technology. Large populations of CD11b+CD45lo cells were identified in buffy coats and stained non-specifically for intracellular antibodies including cytokeratin. The amount of CD11b+ cells misidentified as CTCs varied among patients; accounting for 33–100% of traditionally identified CTCs. Cells captured with vimentin had a higher frequency of CD11b+ cells at 41%, compared to 20% and 18% with MUC1 or EpCAM, respectively. Cells misidentified as CTCs ultimately skewed PD-L1 expression to varying degrees across patient samples. Interfering myeloid populations can be differentiated from true CTCs with additional staining criteria, thus improving the specificity of CTC identification and the accuracy of biomarker evaluation.