Non-steroidal anti-inflammatory drugs (NSAIDs) are widely used in the treatment of inflammatory disease, and their anti-inflammatory effects are believed to result from their ability to inhibit the formation of prostaglandins by prostaglandin H synthase (COX). Two forms of prostaglandin H have been identified, COX-1 and COX-2. The former seems to be constitutively expressed in a variety of tissues while the high expression of the latter has been reported in colorectal tumors. NSAIDs have been shown to be effective in reducing human colorectal cancers and possibly breast and lung cancers. While the exact mechanism(s) by which NSAIDs function has not been elucidated, they could potentially play a critical role in detecting, diagnosing and treating inflammatory diseases as well as cancer. The present invention relates to screening methods for the identification of agonistic and/or antagonistic agents for the activation of the promoter region of NAG-1. Additional claims are directed to 1) the DNA sequence of NAG-1, 2) compositions containing the NAG-1 sequence and 3) methods for treating cancer patients using NAG-1.