Assertion: bone marrow's cell | /r/AtLocation | the bone marrow
Facets:
value: from precursor cells
type: OTHER
value: like macrophages
type: MANNER
Source sentences:
text: Like macrophages, mast cells originate in the bone marrow from precursor cells lacking cytoplasmic granules.
text: In blood cancers such as leukemia, the cancerous cells actually originate in the bone marrow.