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.