AREG and rheumatoid arthritis: To assess the involvement of AREG in the elevated expression of VEGF in affected joints of RA patients, the correlations between their mRNA levels and protein levels in synovial fluid samples were analyzed, and good correlations were found for both the mRNA levels (ρ = 0.700, P = 0.0067) and protein levels (ρ = 0.772, P = 0.0075).