GLI1 and cancer: At the molecular levels, GLI1 is indispensable for many aspects of cancer cell property in terms of the transcriptional regulation of downstream target genes, including BHLHE41 for microsatellite instability [19], ABCG2 for chemoresistance [20], SNAI1 for epithelial-mesenchymal transition [21], BCL2 for anti-apoptosis [22], and BMI1 and NANOG for stemness [23–25].