We investigated the expression pattern and intensity of endogenous markers of acute and chronic hypoxia (HIF-1α, GLUT-1 and CA IX), proliferation (Ki67) and mTOR status [using an antibody against the ribosomal protein S6 phosphorylated on serines 235/236 (p-rpS6) as a surrogate marker] in surgical resection specimens of 10 anaplastic astrocytomas and 11 glioblastomas. Here, RPS6 is linked to glioblastoma.