Letter to the Editor Diagnostic Hematology Acute Lymphoblastic Leukemia with Mature B-Cell

Patients with infantile ALL are fundamentally different from adult patients in that infants have a worse prognosis, which is attrib-uted to the increased relative incidence of MLL gene rearrange-ments [1, 2]. MLL is located on chromosome 11q23 and is a frequent target of chromosome translocations in hematopoietic malignancies. Patients with ALL and MLL rearrangements usu-ally have distinct characteristics, such as organomegaly, marked leukocytosis, and a high incidence of central nervous system leukemia [3, 4]. Most importantly, regardless of the age at pre-sentation, MLL rearrangement in ALL is associated with a poor response to therapy and a poor prognosis [5]. In contrast to lymphoblastic leukemias with MLL rearrange-ments, B-lineage acute leukemias with surface immunoglobulin expression are generally associated with leukemic manifestation of Burkitt lymphoma. Leukemic cells typically have a deeply ba