Based on these findings, we investigated the potential effects of IRA 5 on COX-2 expression and activity in the COX-2-overexpressing colorectal carcinoma cell line HCA-7 [55] with interesting results: Whereas 50 to 100 μM of IRA 5 induced COX-2 expression, 50 μM of that compound inhibited PGE2 production to a substantial degree. The gene discussed is PTGS2; the disease is colorectal carcinoma.