This hypothesis was tested through the investigation of the HER3 status by fluorescence in situ hybridisation (FISH) in a cohort of NSCLC patients treated with gefitinib and previously evaluated for phospho-Akt (P-Akt) expression by immunohistochemistry (IHC), EGFR and HER2 status by FISH and DNA sequencing (Cappuzzo et al, 2004, 2005a, 2005b). This evidence concerns the gene ERBB2 and non-small cell lung carcinoma.