Size- and Invasion-dependent Increase in Cyclooxygenase 2 Levels in Human Colorectal Carcinomas1

Nonsteroidal anti-inflammatory drugs reduce the incidence and mor tality of colorectal carcinoma. Their chemopreventive effects appear to be due to inhibition of cyclooxygenase (COX)-2. Here, we have studied the relationship between the COX-2 mRNA levels and pathological charac teristics in 43 primary colorectal carcinomas. COX-2 levels were signifi cantly higher in tumors with larger sizes and in those with deeper inva sions but were not correlated with whether the patients had metastasis or not. These results suggest that larger carcinomas produce more COX-2 to support their own growth and that COX-2 inhibitors may be effective agents of carcinoma growth suppression.