ETV6 and acute lymphoblastic leukemia: Significantly reduced levels of miR-181a-1, miR-181c and miR-181d in ETV6-RUNX1-positive cases compared with other pediatric BCP-ALL cases can be explained by the fact that this fusion gene and MIR181A1 regulate each other, whereas a double-negative loop involving these two genes seems to contribute to ETV6-RUNX1-driven arrest of differentiation in pre-B ALL [153].