RPS6 and central nervous system cancer: Using longitudinal sections through a LNT-229 glioma cell pellet we were even able to show an intensity reduction after 2 mm for all tested antibodies (Fig 4E), whereas total proteins of RPS6 and 4EBP1 did not present with a staining gradient neither in the investigated primary culture tumor spheroids nor in the longitudinal LNT-229 glioma cell pellet (S1 Fig)