HOXA9 and acute lymphoblastic leukemia: Notably, rearrangement of mixed lineage leukemia (MLL), associated with a recurring chromosomal abnormality that occurs in acute myeloid leukemia (AML) and acute lymphoblastic leukemia is affiliated with poor prognosis and abnormal expression of the HOX gene family, especially HOXA9. Studies have confirmed that HOXA9 expression is closely related to the abnormal proliferation of myeloid cells, which contributes to the survival and development of leukemia41,42.