Der(2)t(2 ; 11)(p21 ; q23), a Variant form of t(2 ; 11), in Biphenotypic Acute Leukemia with T Lymphoid Lineage and Myeloid Lineage Differentiation

Abstract

We describe a patient with biphenotypic acute leukemia (BAL) with T-lymphoid lineage and myeloid lineage differentiation [BAL (T/M)]. Cytogenetic analysis revealed complex chromosomal abnormalities, including der(2)t(2 ; 11)(p21 ; q23). Neither leukemia cells nor T-cell receptor gene rearrangements were detected in the bone marrow samples after four courses of high dose cytosine arabinoside regimen. However, der(2)t(2 ; 11)(p21 ; q23) anomaly persisted in most of metaphases. Fluorescence in situ hybridization (FISH) analysis with a probe for MLL did not detect the split signal. Forty-five cases of hematological disorder with t(2 ; 11)(p21 ; q23) abnormality have been previously reported. The majority of such cases have been classified as myelodysplastic syndrome (MDS) or acute myeloid leukemia (AML). This is the first case BAL (T/M) associated with a t(2 ; 11)(p21 ; q23) anomaly.