Immunohistochemically determined total epidermal growth factor receptor levels not of prognostic value in newly diagnosed glioblastoma multiforme: Report from the Radiation Therapy Oncology Group

Conclusion: Total EGFR protein expression levels, as measured immunohistochemically, do not appear to be of prognostic value in newly diagnosed GBM patients. Given the accumulating clinical evidence of the activity of anti-EGFR agents in GBM and the preclinical data suggesting the important role of downstream mediators as effectors of EGFR signaling, the RTOG is conducting additional investigations into the prognostic value of activation patterns of EGFR signaling, both at the level of the receptor (e.g., EGFRvIII, phospho-EGFR) and at the level of downstream signal transduction pathways (e.g., PI3K, Ras/MAPK pathways).