AZGP1 and head and neck cancer: 8 This is due to its high structural and functional resemblance to lipid mobilizing factor, with the exception of a minor difference in post-translational modification.7 Vidoto et al. have found increased expression of ZAG in head and neck cancer, suggesting that the high levels of ZAG inhibit tumor cells proliferation via immune activity against tumor antigen.9 According to Hasan et al, ZAG inhibits enzyme-mediated tumor invasion and proliferation due to its high structural and functional similarity to class I MHC molecules and its complex with enzymes (macroglobulin/hydrolases).10