EGFR and cancer: EGFR amplification/overexpression is associated with cancer aggressiveness.3,4 Even so, previous studies failed to demonstrate tissue-based assessment of EGFR overexpression to be a reliable biomarker to predict clinical outcomes after anti-EGFR therapies (Data Supplement).11,14-20 These observations are consistent with data from meta-analyses and clinical experience suggesting that, counterintuitively, genomic biomarkers correlate better with response than protein expression, perhaps because of technical limitations associated with assessment of immunohistochemistry staining.31-34