The clinical value of patient-derived glioblastoma tumorspheres in predicting treatment response

Background. Advances from glioma stemlike cell (GSC) research, though increasing our knowledge of glioblas- toma (GBM) biology, do not in uence clinical decisions yet. We explored the translational power of GSC-enriched cultures from patient-derived tumorspheres (TS) in predicting treatment response. Methods. The relationship betweenTS growth and clinical outcome was investigated in 52 GBMs treated with sur- gical resection followed by radiotherapy and temozolomide (TMZ).The effect onTS of radiation (6 to 60 Gy) and of TMZ (3.9 \u3bcM to 1 mM) was related with patients\u2019 survival. Results. Generation of TS was an independent factor for poor overall survival (OS) and poor progression-free survival (PFS) (P 12 Gy of matchedTS (P = .0484). A direct relationship was found between sensitivity ofTS toTMZ and patients\u2019 survival (P = .0167 and P = .0436 for OS and PFS, respectively). Importantly, values forTMZ half-maximal inhibitory concentration