There are ongoing promising initial studies which have identified CTCs in the peripheral blood of glioma patients using physical separation techniques followed by IF for markers, such as GFAP, nestin, and a telomerase promoter-based assay, or iCHIP using the STEAM panel that consisted of SOX2, tubulin beta-3, EGFR, A2B5, and c-Met. Here, GFAP is linked to central nervous system cancer.