EGFR variant III (EGFRvIII) is a truncated, constitutively active mutant form of EGFR that results from an in-frame deletion of exons 2-7. EGFRvIII is expressed in various cancers, most notably glioblastoma, where it is expressed at a frequency of 25-30%. Although complicated by the fact that it is often co-expressed with amplified EGFR, EGFRvIII is a potential therapeutic target.
