A survey of the expression profiles of protein phosphatases in cells exposed to another EGFR TKI erlotinib (Tarceva) revealed that the drug caused a significant reduction in the expression of DUSP6/MKP-3, a result confirmed at the mRNA and protein level in EGFR mutant NSCLC cells in the presence of gefitinib. This evidence concerns the gene DUSP6 and non-small cell lung carcinoma.