Is acute lymphoblastic leukemia with mature B-cell phenotype and KMT2A rearrangements a new entity? A systematic review and meta-analysis

Abstract

The association between mature B-cell phenotype and KMT2A rearrangements in acute lymphoblastic leukemia is a very rare finding. It identifies a group of patients with similar clinical and biological characteristics that clearly differs from the entity B-cell lymphoblastic leukemia/lymphoma with t(v;11q23)/KMT2A-rearranged, which typically presents an immature pro B-cell phenotype. We describe the clinical-biological characteristics and disease outcome of three pediatric ALL patients with these features treated at our institution, and review 28 cases described in the literature. Most cases occur in children under 2 years-old, presenting a mature B-cell phenotype that uniformly expresses cytoplasmic and surface IgM with lambda light chain restriction, with heterogeneous co-expression of immaturity antigens. Patients do not have MYC rearrangements and all show KMT2A abnormalities, with 76% presenting t(9;11)(p21;q23)/MLLT3-KMT2A. These patients have an unfavorable clinical outcome and a 48% relapse rate. In-depth knowledge of this disease entity is needed to improve outcome.

Keywords:

• Acute lymphoblastic leukemia
• mature B-cell phenotype
• t(911)(p21q23)
• KMT2A-MLLT3

Correction Statement

This article has been corrected with minor changes. These changes do not impact the academic content of the article.

Author contributions

Gloria Hidalgo and Margarita Ortega designed the study and wrote the manuscript. Carlos Palacio and Laura Gallur interpreted cytometry data. Gloria Hidalgo, Margarita Ortega and Noemi Martínez interpreted cytogenetic data. Adoración Blanco and Bárbara Tazón analyzed molecular data. Gloria Hidalgo and Margarita Ortega performed the statistical analysis. Laura Murillo, Pablo Velasco and Cristina Diaz Heredia were responsible for the patients and performed clinical evaluations. All authors reviewed the manuscript and approved the final version.

Disclosure statement

The authors declared that they have no potential conflicts of interest.

Additional information

Funding

This work was supported by the FERO Foundation under Grant 3281.