Furthermore, L-GMPs in the BM of Il21−/− AML mice, in spite of identical cell viability, showed increased phosphorylation of IKBα and decreased phosphorylation of p38-MAPK, indicative of altered NF-κB and p38-MAPK signaling activity (Figures 2I–2K and S3B). Here, IL21 is linked to acute myeloid leukemia.