The high-mobility group A1 (HMGA1) protein is a non-histone architectural nuclear factor and participates in diverse biological processes, including gene transcription, embryogenesis, cell cycle regulation, apoptosis, and even neoplastic transformation. In our study, glioma stem cells (GSCs) expressing the surface marker CD133 from human glioblastoma cell line U251 were isolated using MACS column and were analyzed using immunofluorescence and flow cytometry (FCM). The different expression of HMGA1 was detected using real-time RT-PCR and Western blot at transcriptional and translational levels between U251 and isolated GSCs. The results show that GSCs were successfully isolated from U251 and cultured in serum-free medium (SMF). The percentage of GSCs in U251 was 0.32%+/- 0.07%. HMGA1 expression was significantly higher in GSCs than in glioblastoma cells (P < 0.05), up to 6.13 +/- 0.25-fold and 2.75 +/- 0.99-fold at transcriptional and translational levels, respectively. These results indicated HMGA1 is overexpressed in GSCs as compared to glioblastoma cell line U251, which points to the expression of HMGA1 being closely related to malignant proliferation, invasion, and differentiation of tumors from the prospective of tumor stem cells (TSCs). We conclude that HMGA1 may be a potential biomarker and rational therapeutic target for glioblastoma and GSC. (C) 2011 Published by Elsevier B.V.