The role of cyclooxygenase-2 in the pathogenesis of skin cancer.

Prostaglandin synthesis occurs via the coordinate action of a phospholipase that liberates arachidonic acid from membrane phospholipids and a cyclooxygenase (COX) that converts the free arachidonic acid to prostaglandins. Several lines of evidence suggest that prostaglandins play a role in carcinogenesis. Two isoforms of COX have been described. COX-2 is highly regulated and induced by inflammation while COX-1 is considered primarily a housekeeping form. The acute up-regulation of COX-2 by UV radiation suggests that it may contribute to photocarcinogenesis in the same way that COX-2 has recently been shown to contribute to colon cancer.