We first evaluated ABCG2 expression as total protein level (Fig 1A) and plasma membrane level (Fig 1B) in a panel of NSCLC cell lines showing sensitivity (HCC827, H292) or resistance (H460, H1299, SKMES-1, A549, Calu-1 and SKLU-1) to gefitinib. This evidence concerns the gene ABCG2 and non-small cell lung carcinoma.