In addition, osteopontin expression was completely absent in the bone marrow of tumor-bearing mice injected with MDA-MB-231GFP/Luc2 cells plus MC3T3-E1 cells when compared to mice injected with either MDA-MB-231GFP/Luc2 cells plus EO-231 cells or MDA-MB-231GFP/Luc2 cells alone (Fig. 4). Here, SPP1 is linked to neoplasm.