ABCG2 and lung cancer: MEOX2 overexpression resulted in cisplatinum dose-dependent inducible GLI-1 gene expression at the gene promoter level associated with chemoresistance in lung cancer cells, which likely correlates with previous reports in which inhibition of the SHH-GLI1 axis is involved in cancer drug resistance by a lung cancer stem-like cell side population [37] through a direct transcriptional target action in the ABCG2 gene promoter sequence [38].