SOX9 and neoplasm: IHC staining of these xenograft tumours for previous stem cell-like markers, compared to the control xenograft tumours, showed that the percentage of CD44, NANOG, SOX9, SOX2 positive cells was reduced in the STC1-silenced group, and STC1 shRNA and circUBA2 co-transfection played a reversal role (Fig. S12).