Abstract 5367: Identification and clinical value of the circulating tumor cells (CTCs) in the colorectal cancer

Abstract

Abstract The number of circulating tumor cells (CTCs) hase been found as a promising predictive and diagnostic biomarker of colorectal cancer (CRC). The purpose of the study was to enumerate and characterize CTCs from the CRC patients and evaluate the correlation with the clinical stages.Peripheral blood from 57 CRC patients and 6 healthy donors were subjected to isolate CTC by a negative selection (EasySepTM) method. The CTCs were detected by the immunofluorescence staining with the tumor cell markers such as epithelial cell adhesion molecule (EPCAM) and cytokeratin (CK) antibodies and counted them. The extent of positive expressions of EPCAM and cytokeratin (CK) proteins were used to characterize the CTCs and the subpopulations were correlated with the tumor stages of the CRC patients. P<0.05 was considered as statistically significant.CTCs were detected in 72% (41/57) of the CRC patients. Comparing to the healthy donors (HD), the CTC count was higher (p=0.0062) in the CRC patients. In addition, CTC clusters were found in 32% (18/57) of patients with CRC while total CTCs were significantly higher than the cluster count (p=0.001). Among the CRC patients, CTCs were more abundant in the advanced stages compared to the early stages (p=0.0019). Moreover, we found the length of the individual CTCs were significantly larger than the CTCs in the cluster (p<0.0001) and significantly correlated (p=0.036) with the tumor stages. However, we identified the EPCAMPosCkPos subclones in 38 (93%) out of 41 CTC positive cases and a median of 8.0 (range: 0-60) CTCs were counted. In contrast, EPCAMPosCkNeg subpopulations were detected in 27 (66%) patients and the median CTC count was 2.0 (range: 0-18). Interestingly, EPCAMPosCkPos CTC subclones were significantly higher (p=0.011) than EPCAMPosCkNeg subclones, and the number of EPCAMPosCkPos CTCs was merely associated (p=0.0068) with the tumor stages. We conclude that the morphological and phenotypic features of the CTCs are closely relevant to the clinical stages, which could provide vital information to improve the patient stratification and treatment selection. Citation Format: Faysal-Bin Hamid, Farhad Islam, Cu-Tai Lu, Marco Matos, Tracie Cheng, Vinod Gopalan, Alfred King-yin Lam. Identification and clinical value of the circulating tumor cells (CTCs) in the colorectal cancer [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 5367.