Background

The purposes of the study were to enumerate and characterise the circulating tumour cell (CTC) and cluster/micro-emboli (CTM) in blood from patients with colorectal carcinoma (CRC) as well as to investigate their clinical relevance.

Methods

Peripheral blood of six healthy donors (control) and sixty-two patients with CRC were collected to isolate CTCs by an immunomagnetic negative selection approach. EPCAM and cytokeratin 18 (CK18) antibodies were used to identify the CTCs. The size and the phenotypic variations were evaluated to characterise these isolated CTCs. Additionally, mRNA expressions of the CTCs and the corresponding primary carcinoma were assessed using a multi-gene panel to determine the cellular heterogeneities between CTCs and primary carcinoma.

Results

We detected CTCs and CTMs in 72% (41/57) and 32% (18/57) of the patients with CRC, respectively. The total number and length were significantly higher (p<0.0001) in the CTCs than the CTMs. CTCs, especially EPCAM^PositiveCK18^Posositve subclones, were detected more in the patients with advanced pathological cancer stages when compared to those with early cancer stages (mean: 12.5 vs 4.0, p=0.0068). mRNA profiling of CTCs unveiled three different CTC subtypes expressing epithelial, epithelium-mesenchymal transition (EMT) and stemness signatures, which were different from those of the primary carcinoma. The expressions of EPCAM, HRAS, BRAF, TP53, SLUG, TWIST1, CD44 and MMP9 of CTCs were altered when compared to the primary tumours in patients with CRC.

Conclusion

Our findings provide insights into the biology of the CTC, presence of heterogeneous CTC populations in CRC and differential expression of genes in different pathological stages of CTC which can improve the management of patients with CRC.

中文翻译：

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结直肠癌患者循环肿瘤细胞的计数、特征及临床病理意义

背景

该研究的目的是枚举和表征结直肠癌 (CRC) 患者血液中的循环肿瘤细胞 (CTC) 和簇/微栓子 (CTM)，并研究它们的临床相关性。

方法

收集 6 名健康供体（对照）和 62 名 CRC 患者的外周血，通过免疫磁性阴性选择方法分离 CTC。EPCAM 和细胞角蛋白 18 (CK18) 抗体用于鉴定 CTC。评估大小和表型变化以表征这些分离的 CTC。此外，使用多基因面板评估 CTC 和相应原发癌的 mRNA 表达，以确定 CTC 和原发癌之间的细胞异质性。

结果

我们分别在 72% (41/57) 和 32% (18/57) 的 CRC 患者中检测到 CTC 和 CTM。CTC 中的总数和长度显着高于 CTM（p<0.0001）。CTC的，尤其是EPCAM^正CK18 ^Posositve亚克隆，比起那些与癌症的早期阶段，当检测到在治疗晚期癌症病理分期以上（平均值：12.5 VS 4.0，p = 0.0068）。CTC 的 mRNA 分析揭示了三种不同的 CTC 亚型，它们表达上皮、上皮-间质转化 (EMT) 和干细胞特征，这与原发癌不同。与 CRC 患者的原发肿瘤相比，CTC 的 EPCAM、HRAS、BRAF、TP53、SLUG、TWIST1、CD44 和 MMP9 的表达发生了改变。

结论

我们的研究结果提供了对 CTC 生物学、CRC 中异质性 CTC 群体的存在以及 CTC 不同病理阶段基因差异表达的见解，这可以改善 CRC 患者的管理。