结直肠癌（CRC）是香港第二大癌症死因。本研究检验了一种假设，即利用ARB101抗体对循环肿瘤细胞（CTC）的分析可用作CRC检测、进展和治疗反应的工具。ARB101抗体被用于对CRC患者的福尔马林固定、石蜡包埋（FFPE）组织切片和循环肿瘤细胞（CTCs）中CDH17表达的研究。使用ARB101抗体，在98/100（98％）的结直肠癌组织中观察到最高的灵敏度，相比之下，胃癌（72％）和胰腺癌（84％）分别为72/100和27/32。在远处转移（肿瘤节点转移【TNM】阶段IV）的CRC中，CDH17的免疫反应性显著高于非远距离转移（TNM阶段I至III）的CRC。与c-erbB2（8％）和表皮生长因子受体（EGFR）靶向抗体（37％）相比，ARB101抗体也表现出更高的敏感性，并具有显著性（p<0.0001）。ARB101阳性的CTCs在64/83（77％）TNM阶段I至IV的CRC患者中被检测到。此外，在手术前和手术后检测到的TNM阶段I至III CRC患者的ARB101阳性CTCs具有统计学意义（p<0.0001）。通过ARB101抗体检测CTC可能作为潜在的非侵入性方法用于CRC检测、进展和治疗反应的监测。

Colorectal cancer (CRC) is the second leading cause of cancer deaths in Hong Kong. We tested the hypothesis that circulating tumor cell (CTC) analysis by ARB101 antibody could be used as a tool for CRC detection, progression, and therapy response.ARB101 antibody was used for investigation of CDH17 expression in formalin-fixed, paraffin-embedded (FFPE) tissue sections and circulating tumor cells (CTCs) of CRC patients.Using ARB101, highest sensitivity was observed in 98/100 (98%) colorectal cancer tissue compared to 72/100 gastric cancer (72%) and 27/32 pancreatic cancer (84%). Immunoreactivity of CDH17 was significantly higher in distant metastatic (tumor-node-metastasis [TNM] stage IV) than non-distant metastatic (TNM stage I to III) CRC. ARB101 antibody also manifested the higher sensitivity than c-erbB2 (8%) and epidermal growth factor receptor (EGFR)-targeting antibodies (37%) with the significance (p < 0.0001). ARB101 positive CTCs were detected in 64/83 (77%) TNM stage I to IV CRC patients. Furthermore, ARB101 positive CTCs detected in TNM stage I to III CRC patients before and after surgical operation are statistically significant (p < 0.0001).CTC detection by ARB101 antibody could serve as a potential non-invasive approach for CRC detection, progression, and monitoring of treatment response.