IL1B and rheumatoid arthritis: To gain further insight into the role of E2F2 in the pathology of RA, we chose genes known to be involved with RA pathology, including ki67, a marker to measure the proliferative state of RASFs20, cytokines such as TNF-α, IL-1α, IL-1β, IL-6, PGE221, and matrix metalloproteinases which can degrade extracellular matrix (ECM), including MMP2, MMP9, and MMP13, which in turn lead to the invasion of RASFs to adjacent bone or cartilage22.qRT-qPCR was used to test the expression of these genes.