EGF and arthritic joint disease: Both FGF1 and FGF2 have been observed to be upregulated in the synovial tissue of human subjects with RA [25] and significantly worsened clinical symptoms in a rat adjuvant-induced model of arthritis [26], while at least one polymorphism of the EGF gene (rs4444903) has been shown to significantly affect EGF production [27].