In a study by Wang et al., knockdown of S100A4 was shown to inhibit lung metastasis of MDA-MB-231 cells,30 and a study by Liu et al. reported that recombinant S100A4 promoted migration of 4T1 mouse breast cancer cells to the lung, liver, and kidney.31 Therefore, S100A4 is an attractive therapeutic target for the metastasis of breast cancers to multiple organs, including bone. The gene discussed is S100A4; the disease is breast carcinoma.