ABCG2 and non-small cell lung carcinoma: As additional evidence to support that α2δ1+ NSCLC cells have the capacity of differentiation, the expression of stem cell-related molecules including α2δ1, SOX2, and ABCG2 was also downregulated in purified α2δ1+ A549 and H520 fractions after cultivation in FBS-containing medium for 2 weeks (Fig. 2H).