GLI1 and melanoma: To further investigate the effect of GLI1 on PMN-MDSC recruitment, we performed an in vitro invasion assay where PMN-MDSCs were seeded over a Transwell membrane pre-coated with Matrigel (top chamber) and CM obtained from B16F10 or YUMM1.7 melanoma cells transduced with pBABE or pBABE-GLI1 were used as a chemo-attractant in the bottom chamber (Fig. 2E).