AZGP1 and head and neck squamous cell carcinoma: Poropatich et al also found an up-regulation of ZAG in the low grade oropharyngeal squamous cell carcinoma with significantly longer recurrence free survival.17 According to Vidotto et al, increased ZAG expression induces an immune response against tumor antigens and mucosal breakdown by proteolytic enzymes in Head and Neck Squamous Cell Carcinoma.9 This could imply that ZAG inhibits tumor proliferation and differentiation.