ERG and precursor B-cell acute lymphoblastic leukemia: Of note, Stanulla et al. were the first to describe the IKZF1pos profile that co-occurred with deletions in CDNK2A/B, PAX5, or PAR1 in the absence of ERG deletion, referring to it as the IKZFplus subset, which defined poor prognostic subgroups among pediatric B-ALL [39].