HMGN1 and acute myeloid leukemia: However, it is important to note that most of the AML cell lines tested were diploid for 21q22/HMGN1 and none have known mutations in HMGN1, yet they still exhibited relative HMGN1 dependency (Supplementary Fig. 1d), raising the possibility that HMGN1 is important for AML even in cases without chr21 amplification.