Greater than 40% of glioblastomas (GBM) harbor focal amplification of the EGFR locus and there is evidence to suggest that these are driver alterations in these patients, making the EGFR pathway a potential therapeutic target in some clinical settings. Moreover, this alteration is relatively specific for GBM with very few other diffusely infiltrative gliomas having been shown to carry focal amplification of this locus (<3%). In GBM, this alteration frequently occurs in combination with other alterations of EGFR including polysomy 7, intragenic inframe deletions (e.g. EGFRvIII), and/or somatic point mutations. Based on current evidence, the independent predictive value of EGFR amplification in GBM is unclear. The relationship between individual and concurrent EGFR alterations and clinical response to small molecular inhibitors targeting EGFR is currently under investigation in clinical trials.

EGFR has been reported to show increased expression in a subset of bladder cancers and may be a targetable alteration in some clinical settings.

Copy number gain (amplification) of EGFR has been reported in up to 30% of esophageal adenocarcinomas and less than 5% of gastric adenocarcinomas. According to some studies increased EGFR protein expression may be associated with decreased survival. This alteration may have therapeutic implications in some settings.

In colorectal cancer, EGFR gene amplification is associated with sensitivity EGFR-targeted therapies, such as Erbitux and Vectibix.

This gene is a known cancer gene.