Spheres derived from the lung adenocarcinoma cell line, H1299, exhibited a contraction of the S-phase of the cell cycle compared with monolayer cultures (Fig. 1d), consistent with a non-replicating state, and enrichment of the stemness markers KLF4, Notch-1, Nanog and Sox2 (Fig. 1e). This evidence concerns the gene KLF4 and lung adenocarcinoma.