The epidemiology of EGFR mutations

The discovery of mutations in the tyrosine kinase (TK) domain of the EGFR in lung cancers has generated enormous interest since they appear to be associated with sensitivity to EGFR-tyrosine kinase inhibitors (TKIs). These mutations appear to occur predominantly in highly select patient populations: East Asian ethnicity, female gender, never-smoker status and adenocarcinoma subtype. While the mutational status of EGFR appears to be of considerable importance in determining response to EGFR-TKIs in lung cancer, it is not the sole factor. Accurate prediction of therapeutic response to EGFR-TKIs is likely to require a complete understanding of the erbB gene family members and their role in cancer pathogenesis and progression. Further molecular-based studies are required to analyse the biological functions of different EGFR-TK mutations and to assess their effect on sensitivity to EGFR-TKIs. Epidemiological studies may identify other possible factor(s) associated with the incidence of EGFR-TK mutations or with response to EGFR-TKIs.