Fig. 6.

EGFR abundance correlates better with p-rpS6 and p-PKC than with p-Akt in primary human glioblastoma tumors. Normal brain (autopsy specimen) or primary human glioblastoma tumors obtained from the Brain Tumor Research Center at UCSF were lysed and immunoblotted. In EGFR immunoblot, the top band has mobility of wild-type EGFR, whereas the lower band has mobility consistent with mutationally activated EGFR. Abundances of EGFR, p-PKCα, p-PKC (pan), p-rpS6, and p-Akt in normal brain and primary human glioblastoma tumors are quantified in fig. S4. Samples showing abundant p-PKC in the absence of high concentrations of EGFR may be activated by alternative RTKs (17).