We further demonstrated that transfection of S727A point-mutated STAT3 inactivated the Col17a1 promoter in enriched TICs (Fig. 4k), and transfection of S727E point-mutated STAT3 activated the wild-type (WT) Col17a1 promoter activity but not the eighth binding site-mutated Col17a1 promoter in bulk cancer cells (Fig. 4l). Here, COL17A1 is linked to cancer.