IER2 and acute myeloid leukemia: Further, circRNF220 can distinguish AML from ALL and other hematological malignancies, while high circRNF220 expression is an unfavorable prognostic marker of recurrence, due to its role in sequestration of miR-30a, which increases MYSM1 and IER2 expression and is implicated in AML relapse (Liu et al., 2021).