ABCG2 and non-small cell lung carcinoma: In view of our previous works on gefitinib uptake [28] and metabolism [29] in NSCLC cell lines, and considering our experience on aminoacid [30] and nutrient transport [31], in this paper we characterized the efflux of gefitinib in a panel of NSCLC cell lines, we analyzed the effect of ABCG2 silencing on accumulation, efflux and uptake of gefitinib and the effect of ABCG2 overexpression on the regulation of a number of drug transporter genes and on the uptake of gefitinib and of various metabolites.