GLI1 and cancer: Upactivation of the HH signaling pathway in cancer cells induces GLI1 and SHH overexpression, which increases the expression of proangiogenic factors, including VEGF-A, MMP-2, MMP-9, heparanase, and cysteine-rich angiogenic inducer 61 (Cyr61), in different tumor cells [118,124,126].