Our previous study showed that aspirin induced apoptosis of esophageal cancer cells in vitro by inhibiting the pathway of NF-kappaB downstream regulation of cyclooxygenase-2. The purpose of this study was to determine if similar changes occurred in vivo in the tumors of patients with SCC of the esophagus who were given a preferential COX-2 inhibitor, meloxicam. Fifty-three patients who had an esophagectomy for SCC were allocated randomly to either a Treatment group (n = 25) or a control group (n = 28). Patients in the Treatment group were given 7.5 mg/day of meloxicam, for between 10 and 14 days before surgery. Patients in the control group did not take any type of NSAID during this time interval. Samples of the tumor taken from the resected specimens were collected. Proliferation and apoptosis were measured by flow cytometry. The concentration of 6-keto-prostaglandin F-1 alpha in cancer tissue was determined by radio-immuno-assay. Expression of COX-2 mRNA was measured with RT-PCR and COX-2 protein levels with Western blot analysis. Nuclear NF-kappaB and cytoplasmic IkappaB protein levels were determined by electrophoretic mobility shift assay and Western blot, respectively. There were significantly more apoptotic cells in the tumors of patients who were using meloxicam. It also decreased the levels of COX-2 mRNA, COX-2 protein and nuclear NF-kappaB protein and increased the cytoplasmic IkappaB protein in the cancer. We conclude that meloxicam induces apoptosis in SCC of the esophagus in vivo by inhibiting the pathway of NF-kappaB downstream regulation of COX-2. (c) 2007 Wiley-Liss, Inc.