Identifying circulating glioma cells and their clusters as diagnostic markers by a novel detection platform

Abstract

Identifying circulating glioma cells and their clusters as diagnostic markers by a novel detection platformDear editor:Diffused glioma is the leading cause of central nervous system tumor-related deaths worldwide. 1 As a non-invasive and convenient bio-marker, despite that circulating tumor cells (CTC) and their clusters show great feasibility in tumor diagnosis and management, 2 their isolation and identification remain challenging, limiting further clinical application. [3][4][5][6][7] Therefore, more efficient detection platforms are urgently required in this field. This inspired us to fabricate a novel platform to detect circulating glioma cells and their clusters for further evaluated their value in tumor diagnosis and management, and highlight the wider potential of CTC for clinical application.In this study, we performed a novel isolation method by size of epithelial tumor cells device. The isolation is carried out using a biocompatible parylene polymer membrane with a pore diameter of 8 μm under a high flow rate, enriching for CTCs without requiring tumor cell-specific capture antibodies.To test the capture efficiency of this device, two common malignant glioma cell lines, U87 and U251, were selected and spiked into healthy donors' blood samples. In detecting spiked U87 cells from blood samples at concentrations of 5, 10, 20, 50, 100, and 150 cells per 5 ml, the capture efficiency were 86.0%, 87.0%, 86.5%, 86.0%, 91.3%, and 92.9%, respectively. The capture efficiency were 80.0%, 77.0%, 81.5%, 78.6%, 84.3%, and 86.2% when detecting U251 cells from blood samples at above concentrations (Figure 1A-C). Besides, CTC cluster was not observed in any test, confirming that it was not artifact.We then investigate feasible identification methods for glioma CTC. Our data showed that Wright's staining, one convincing and feasible identification method, 8 could not distinguish glioma CTC from other brain tumors', indicating that identification methods based on tumor features cannot define CTC origin, which limit its diagnostic value (Figure 4A-C; Tables S1 and S2). However, highly specific identification methods targeted GBM-derived CTC, represented by STEAM staining, an antibody cocktail basedThis is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Prognostic and Predictive Biomarkers in Gliomas

“…Circulating tumor cells (CTCs) are cells that are released into the bloodstream from primary tumors and metastatic deposits [ 251 ] ( Figure 2 ). In many recent studies, CTCs have been found in the blood of GBM patients [ 252 , 253 , 254 , 255 , 256 , 257 , 258 , 259 , 260 , 261 ]. GBMs discharge CTCs with invasive mesenchymal properties into the bloodstream, revealing mutations that were not observed in the primary tumor [ 256 , 260 ].…”

“…Due to the lack of regularly expressed tumor markers and high inter- and intra-tumor heterogeneity, detecting glioma CTCs has been difficult [ 252 ]. Despite challenges in isolating, detecting, and diagnosing CTCs, a number of studies have now been published that outline new and effective detection strategies, but none has yet received widespread recognition and validation that would progress clinical acceptance [ 257 , 259 , 267 ]. The presence of CTCs correlates with the risk of metastasis and the frequency of relapse after surgery [ 253 ].…”

Circulating Tumor Cells and Breast Cancer Metastasis: From Enumeration to Somatic Mutational Profile

“…Peripheral blood samples were collected before and after the systemic therapy of patients with and without tumor metastasis, respectively. CTCs were isolated by the CTCBIOPSY ® system following the manufacturer’s protocol (Wuhan YZY Medical Science and Technology Co., Ltd., Wuhan, China) [ 15 , 16 ]. The initial 1 mL of blood was discarded to avoid the contamination of epithelial cells.…”

A Novel Karyoplasmic Ratio-Based Automatic Recognition Method for Identifying Glioma Circulating Tumor Cells

“…Because complete separation of CTCs and blood cells can barely be achieved by "positive enrichment," "negative depletion," or physical isolation, researchers need to further screen out CTCs from thousands of isolated nucleated cells. Among the various identification approaches, immunofluorescence (IF) staining is currently the most widely used technique (7)(8)(9)(10)(11)(12)(13)(14). However, the use of antibodies against one or more protein surface markers will render the detection fragile to changes in the expression level of the selected marker, while targeting several proteins using an antibody cocktail will increase the risk of false-positive results and high background levels because healthy cells might express one or more of the included markers (7,9,11,14).…”

“…Among the various identification approaches, immunofluorescence (IF) staining is currently the most widely used technique (7)(8)(9)(10)(11)(12)(13)(14). However, the use of antibodies against one or more protein surface markers will render the detection fragile to changes in the expression level of the selected marker, while targeting several proteins using an antibody cocktail will increase the risk of false-positive results and high background levels because healthy cells might express one or more of the included markers (7,9,11,14). Thus, we believe that the development of other identification parameters will be an important component of IF staining for CTC identification.…”