Quantitative TaqMan®-PCR analysis of specific mRNA for prostanoid receptor subtypes EP1, EP2, and EP3 demonstrated a significant higher expression in the synovium of JT, OA, and RA patients compared to controls (P < 0.05) (Figures 4(a), 5(a), and 6(a)), except for the EP4 specific mRNA that was not significantly elevated in JT patients (Figure 7(a)). Here, PTGER4 is linked to rheumatoid arthritis.