CD34 and glioblastoma: Glioblastoma stem cells present several biomarkers used for identification, such as CD133, nestin, musashi-1, CXCR4, CD15, CD34, CD44, SOX2, L1CAM, and A2B5, however, neither being exclusively characteristic for GSCs [42,43,44,45,46,47,48,49,50,51,52,53,54] (Table 1).