SHH and cancer: Research indicates that Shh signaling plays a role in the development and advancement of different cancers, including oral carcinoma, through two molecular mechanisms: (a) the classical or canonical pathway, which involves the binding of Shh ligands and the activation of the GLI (glioma-associated oncogene) family, and (b) the non-canonical pathway, which involves cross-talk or downstream activation of one of the pathway members [125].