In this study, we found IL-4 had few effects on osteoclastogenesis in the presence of RANKL in vitro experiments, whereas the number of osteoclasts was significantly influenced in the presence of IL-4 during bone metastasis of CRC in vivo, and thus we thought IL-4 enhanced the number of osteoclasts indirectly by promoting the proliferation of early OCPs. This evidence concerns the gene IL4 and colorectal carcinoma.