Additional patients with newly diagnosed distal CRCs were recruited under a separate protocol, approved by the Irish Medicines Board and Beaumont Hospital Ethics Committee, for treatment for 5 -7 days with the selective COX-2 inhibitor rofecoxib at a dose of 25 mg daily. Tumour was sampled endoscopically at day 0 and again on completion of therapy and was placed in RNAlater. Compliance with drug therapy was monitored by measurement of whole-blood monocyte COX-2 activity as previously described (Panara et al, 1995) .