In addition, previous studies interested in clinical (gender, Karnofsky index) or biological (EGFR expression, HER2 expression) factors predictive for response or survival for patients treated with gefitinib reported contradictive or negative results, except for those with adenocarcinoma histological subtype and nonsmoking history, which predict a better survival (Miller et al, 2004). This evidence concerns the gene ERBB2 and adenocarcinoma.