The HIF-1 axis suppresses the innate and adaptive immune response by inducing the secretion of immunosuppressive factors (prostaglandin E2 and transforming growth factor-β) [86], expression of programmed death protein-ligand 1 (PD-L1) on cancer cells [87], and reducing tumor-associated antigen presentation via major histocompatibility complex class I (MHC-1) [88]. Here, HIF1A is linked to cancer.