1 ︳INTRODUCTION
The rearrangement of the c-MYC gene is the hallmark of Burkitt leukemia
(BL), which is a kind of mature B-cell neoplasms, accounting for about
2% of acute pediatric leukemia. The well characterized immunophenotype
for BL is mature B cell phenotype, including CD10, CD19, CD20, CD22,
CD79a and sIgM, without the expression of CD34 and terminal
deoxynucleotidyl transferase (TdT) 1, 2. Except for
BL, c-MYC rearrangement can also occur in other B-cell NHL, such as
diffuse large B-cell lymphoma (DLBCL), multiple myeloma (MM) and so
on3. Nevertheless, c-MYC rearrangement is also
occasionally detected in acute lymphoblastic leukemia (ALL) with an
immature B cell immunophenotype of B cell precursor (BCP-ALL). Although
the “WHO Classification of Tumors of Hematopoietic and Lymphoid
Tissue” has noted these rare cases of BL exhibiting a precursor B-cell
phenotype (termed herein “pre-BLL”), the characteristics of it are
poorly understood for its rarity4. Because of the
overlapping features between BL and pre-BLL, the diagnosis is often
delayed and the treatment is controversial, making the clinical
management complicated. In order to clarify the clinical and biological
characteristics and the treatment outcome of pre-BLL, we report nine
patients with pre-BLL in this study.