MTT test was performed on HSAEC1, HCC4006 and H1734 cell lines transfected with either the empty vector (mock) or pcDNA3.1-HsNEU3 and then treated or not with 27 nM or 1 μM gefitinib for 36 h post-transfection. Data were normalized on control cells transfected with the empty vector (A). Cell viabilities of mock and NEU3 transfected cells are reported after treatment with either 27 nM (B) or 1 μM gefitinib (C). Data were normalized on control cells without drug. Values are presented as means ± standard error (SE).