In RA, there is often an overproduction of inflammatory cytokines including IL-1, IL-6, and TNF-α, which would be elevated by the mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK), NF-κB, and activator protein-1 (AP-1) signaling cascades. Here, IL1A is linked to rheumatoid arthritis.