The above results, associated with our initial finding of ARNT2 down-regulation in glioblastoma cells deprived of tumorigenic properties, led us to evaluate the role of ARNT2 in the control of glioblastoma cell tumorigenicity using orthotopic xenografts of GBM stem-like cells (6240**, 5706**) expressing either a shControl or a shARNT2. The gene discussed is ARNT2; the disease is glioblastoma.