IKZF1 Alteration in Pediatric B-Cell Acute Lymphoblastic Leukemia: A Single-Center Report on the Frequency of IKZF1 Deletions and Its Subtypes

Introduction: The most prevalent malignancy during childhood is B-cell acute lymphoblastic leukemia (B-ALL). Many genetic variations are the causes of B-ALL. IKZF1 alterations are prevalent in childhood B-ALL cases, which are associated with a poor prognosis. This study examined seventy-two pediatric B-ALL patients for the frequency of IKZF1 alteration and types of IKZF1 deletions. Materials and Methods: In this study, bone marrow aspirate specimens at the stage of diagnosis in pediatric B–ALL patients were used. The diagnosis of B-ALL was performed following cytomorphology, cytochemistry, and immunophenotyping based on the 2016 World Health Organization (WHO) guidelines. ALL translocations, including TCF3-PBX1 fusion, ETV6-RUNX1 fusion, BCR-ABL1 fusion, and KMT2A-AFF1 fusion, were performed on DNA specimens of all patients. IKZF1 status was checked with the SALSA MLPA P335 ALL-IKZF1 probemix Kit. Results: The common-B ALL subtype was detected in 64/72 patients (88.9%). CD2 and CD13 aberrant expressions were found in 5/72 (6.9%) and 7/72 patients (9.7%), respectively. Molecular analysis for translocation revealed the frequency of ETV6-RUNX1 in 12/72 patients (16.7%) and BCR-ABL1 in 3/72 (4.2%). IKZF1 alterations were found in 13/72 patients (18%), of whom 10 (13.9%) had IKZF1 deletions. Three common types of IKZF1 deletions were found. Conclusion: The frequency of IKZF1 deletion in this study is similar to the results already obtained in larger studies. The type of IKZF1 deletion related to poor outcomes has a higher frequency in this study. Because of the relatively high prevalence of IKZF1 deletion, its determination is important for better risk stratification and prognosis in pediatric B-ALL patients.