Taken together, data from Figures 1 and 5 imply that cellular infiltration and osteoclast formation along with increased COX-2 may provide a conducive microenvironment for 4T1 tumor cells to metastasize to the bone, which further augments cellular infiltration and osteoclast formation associated with increased bone damage completing the vicious cycle of osteolytic bone metastasis [19]. This evidence concerns the gene PTGS2 and neoplasm.