Bone marrow TdTOSX+ cells instead expressed significantly higher levels of the early osteoblast transcription factor Runx2 and of the protease Mmp9, while no differences in other osteoblast markers such as Bglap and Alpl were detected between the tumor and bone marrow sorted TdTOSX+ cells (Figure 3—figure supplement 2). Here, MMP9 is linked to neoplasm.