EGFR mutations in GBM cluster in the extracellular (EC) domain and include in-frame deletions (such as the common “variant III” del 6-273) and missense mutations (A289V, A289D, T263P, G598V). Mutations involving residue R108 have been reported in GBM, frequently occurring with other EGFR mutations at amino acids A289, P596, and G598. In vitro studies have shown that R108K mutation leads to increased ligand-binding affinity and shows anchorage-independent growth and tumorigenic potential when stably expressed in NIH-3T3 cells. The predictive and prognostic significance of this mutation at R108 needs further elucidation. Correlation with other clinical and laboratory findings is recommended.