Gene expression of cyclooxygenase-2, group II and cytosolic phospholipase A2 in human colorectal cancer.

The development of intestinal tumours in the Min mouse is influenced by Moml locus, where the group II phospholipase A2 (PLA2-II) gene has been suggested as the candidate gene. Since no causative genetic alterations have been identified in PLA2-II in human colorectal tumours, we tested whether PLA2-II or the cytosolic isoform cPLA2, are dysregulated in human colorectal carcinogenesis. By means of RT-PCR, the expression of these genes and cyclooxygenase-2 (COX-2), which is upregulated in colorectal tumours, were examined. No changes in gene expression of PLA2-II were found in 44 tumours compared to normal mucosa. cPLA2 and COX-2 were upregulated; however, no correlation in expression was found between these genes. Thus, the supply of arachidonic acid provided by PLA2-II/cPLA2 seems not to be the rate limiting step in PGE2 (a prostaglandin/mitogen) formation via COX-2 and PLA2-II plays a minor or no role in human colorectal carcinogenesis.