循环肿瘤细胞（Circulating tumor cell，CTC）是肝癌转移复发的种子。我们经前期工作发现：①患者肝癌组织中补体受体C5aR表达与术前CTC数量相关；②活化肝癌C5a-C5aR通路可增强细胞系的侵袭性、上皮-间充质转化、上调Wnt通路、并增加干性标志物EpCAM表达，而拮抗C5aR可阻断上述效应；③肝癌患者EpCAM+CTC表面亦表达有C5aR。我们由此推测C5a-C5aR通路是促肝癌CTC释放和干性表达的重要因素，检测CTC表面C5aR有助于识别其中具有特殊靶向意义的亚群。本研究将运用小鼠肝癌原位种植模型联合“活体流式”CTC技术，阐明C5a-C5aR通路对CTC释放及干性表达的影响和机制；运用人源肿瘤小鼠移植模型，阐明靶向C5a-C5aR通路的抗CTC释放、抗干性表达作用；结合临床患者资料，评价C5aR作为CTC分子标志物的价值，为肝癌转移复发的防治提供新思路和依据。

Circulating tumor cells (CTCs) play as the potential sources in cancer relapse and distant metastasis. Our previous work found that the expression level of complement component 5a receptor (C5aR) on HCC cell membrane correlated with the cell count of CTCs measured in 7.5 ml of blood before surgery by comparing the expression profiles among resected tumor tissues from different HCC patients. We distinctively found that activation of C5a-C5aR pathway in vitro enhanced the migration of Huh7 cells, promoted the epithelial-mesenchymal transition, actived the Wnt pathway and upregulated the expression of EpCAM. EpCAM+/C5aR+ cells were detected in the CD45-depleted peripheral blood mononuclear cells, and might represent a certain subgroup of CTCs with stem cell-like properties in HCC. We raise the hypothesis that the activation of C5a-C5aR pathway enhances the releasing of CTCs and the stem cell-like properties in HCC. Analyzing the C5aR expression on CTCs helps to recognize for a certain CTCs subtype with targeted value. We aimed to clarify the effect of C5a-C5aR pathway on the releasing and stem cell-like properties of CTCs in HCC by orthotopic transplantation models with in vivo flow cytometry CTCs assay, and probe the protential capacity of C5aR as a therapeutic target in HCC recurrence and molecular biomarker for liquid biopsy.