To visualize the expression profiles of the different components of the prostanoid system within a single-patient group (JT, OA, or RA patients), the data for COX-2, EP1-EP4, mPGEs-1, and PGE-2 were converted to and displayed as fold change over control for that individual group (Figures 8, –10). The gene discussed is PTGER4; the disease is rheumatoid arthritis.