PTGS2 and melanoma: In the present study, we analyzed the effect of a selective COX-2 inhibitor celecoxib --a 1,5 diarylpyrazole with >300-fold selectivity for COX-2 versus COX-1 [25]-- in a model of generalized BM dissemination of left cardiac ventricle-injected B16 melanoma (B16M) cells [26] into healthy and LPS-pretreated mice, to mimic the prometastatic effects of systemic inflammation [26-29].