Status of IKZF1 Deletions in Diagnose and Relapsed Pediatric B-ALL Patients

IKZF1 deletions (ΔIKZF1) are common in precursor B-cell acute lymphoblastic leukemia (B-ALL) and are assumed to have a prognostic impact. We aimed to determine the prognostic implications of ΔIKZF1 and CRLF2 overexpression in pediatric B-ALL. Furthermore, we sought to compare the multiplex polymerase chain reaction (PCR) assay with standard multiplex ligand-dependent probe amplification (MLPA) methods to ascertain IKZF1 status in a clinical context. Seventy-nine diagnoses and 43 relapse B-ALL samples were evaluated for deletions of IKZF1 Δ2-7, Δ4-7, and Δ4-8 by conventional PCR and then sequenced by targeted sequencing. Subsequently, MLPA analysis was performed for ΔIKZF1 detection, and CRLF2 expression was evaluated in 42 diagnose time B-ALL patients by QRT-PCR. ΔIKZF1 was detected in 10 out of 79 diagnose samples (12.66%) and eight of the 43 first relapsed materials (18.60%). Our results revealed no association between survival outcomes with ΔIKZF1 or CRLF2 overexpression status in pediatric B-ALL patients. However, we found ΔIKZF1 was more frequent among relapsed samples, and the deletions showed consistency between diagnose-first/second relapse pairs of samples. These results suggest that ΔIKZF1 may contribute to the development of treatment failure in B-ALL. Furthermore, we demonstrated methodological adjustments in conventional PCR and MLPA for selected alterations in ΔIKZF1.