IKZF1 and acute lymphoblastic leukemia: Precursor‐B cell acute lymphoblastic leukaemia (pre‐B ALL) is often driven by genetic alterations including either activating point mutations, chromosomal reciprocal translocations such as the Philadelphia chromosome t(9;22) or aberrant expression of B cell‐specific transcription factors, for example paired box protein 5 (PAX5) and IKAROS family zinc finger 1 (IKZF1).1, 2