Inhibitory effect of celecoxib administration on BM metastasis in untreated (A and B) and LPS-treated mice (C and D). Mice received either saline or LPS (20 mice per group) 6 h prior to B16M cell injection as above. Ten mice of each group received control chow and the other ten mice received chow containing 16% celecoxib. Treatment was initiated at the time of tumor injection. Mouse killing on day 15 and metastasis assessment was done as above. The experiment was repeated three times. Results are expressed as average metastasis incidence (A and C) and volume (B and D) inhibition percentages determined with respect to animals fed with control chow receiving saline (A and B) or LPS (C and D).