Complex sentence: Inhibitor of DNA Binding 1 (ID1) has been used as a marker for these cells; this allows for tracking EPCs from the bone marrow to the blood to the tumour-stroma and even incorporated in tumour vasculature.
Split into simpler sentences: Inhibitor of DNA Binding 1 (ID1) has been used as a marker for these cells. This allows for tracking EPCs from the bone marrow to the blood to the tumour-stroma and even incorporated in tumour vasculature.