CD44 and lung cancer: In addition, to investigate the effect of ARTN on the maintenance of stemness of lung cancer cells, we performed a stemness sphere-forming assay (Fig. 7I) and examined the difference in the expression of cancer stem cell markers (SOX2, CD44, NANOG, POU5F1, CD133, C-myc, KLF4), and the transcript levels of cancer stem cell markers were significantly reduced (Fig. 7J).