Annexin A1 belongs to the annexin family of Ca2+-dependent phospholipid-binding proteins. Annexin A1 has important opposing properties during innate and adaptive immune responses: it inhibits innate immune cells and promotes T-cell activation. The activation of T cells results in the release of annexin A1 and the expression of its receptor. This pathway seems to fine-tune the strength of TCR signalling. Higher expression of annexin A1 during pathological conditions could increase the strength of TCR signalling through the mitogen-activated protein kinase signalling pathway, thereby causing a state of hyperactivation of T cells. Annexin A1 has also been of interest for use as a potential anticancer drug. Upon induction by modified NSAIDS and other potent anti-inflammatory drugs, annexin A1 inhibits the NF-κB signal transduction pathway, which is exploited by cancerous cells to proliferate and avoid apoptosis. ANXA1 inhibits the activation of NF-κB by binding to the p65 subunit.