CTSG and myelodysplastic syndrome: Based on our in vitro observations, we intravenously co-injected HS5 cells and MDS marrow-derived hematopoietic cells into Nod.cg-Prkdcscid Il2rgtm1wjll (NSG) mice, and observed that differential stromal contact had structural and functional effects on proliferation of MDS precursor cells [40].