Although we and others have shown previously that selective COX-2 inhibitors, such as celecoxib or the omega-3 fatty acid, eicosapentaenoic acid, suppressed proliferation of human NSCLC A549 cells [16], whether knocking down COX-2 gene would affect the proliferation of A549 cells has not been tested. Here, PTGS2 is linked to non-small cell lung carcinoma.