Investigating the pathways involved in S100A9-induced AML cell differentiation revealed that S100A9 induces differentiation via TLR4 and several downstream factors, including p38 MAPK, extracellular signal-regulated kinases 1 and 2 (ERK1/2), Jun N-terminal kinase (JNK), and NF-κB. Here, MAPK8 is linked to acute myeloid leukemia.