Acute myeloid leukemia M2 and t(8;21)(q22;q22) with an unusual phenotype: myeloperoxidase (+), CD13 (-), CD14 (-), and CD33 (-)

Abstract

Cases of myeloid surface antigen-negative acute myeloid leukemia (AML) are rare. We describe the morphological, cytochemical, immunologic, and cytogenetic features of two patients with AML with maturation (FAB M2) and the phenotype MPO+, CD13 (-), CD33(-), CD56(+). Cytogenetic studies demonstrated t(8;21)(q22;q22). These findings suggest an association between the lack of CD13 and CD33 in myeloperoxidase-positive AML and the presence of t(8;21).

Multidimensional Flow Cytometry Immunophenotyping of Hematologic Malignancy

“…Recent reports have also indicated the existence of an important association between specific genetic alterations and the immunophenotypic characteristics of leukemic cells in both AML and ALL, particularly using multivariate phenotypic patterns and considering the extent of antigen expression and its pattern of reactivity (homogeneous vs heterogeneous, unimodal vs multimodal) 23–27. As a matter of fact, in a recent study of 111 patients with AML in whom multivariate information provided by the use of multiple staining analyzed at flow cytometry was obtained, it was shown that the combination of three phenotypic variables (number of major blast cell populations, pattern of CD34/CD15 expression, and reactivity for CD13) was highly sensitive (100%) and specific (99%) for the selection of AML cases carrying PML/RAR‐α gene rearrangements, as demonstrated by the combined use of the reverse transcription‐polymerase chain reaction and fluorescent in situ hybridization (FISH) analysis 25…”

“…Furthermore, some nonspecific myeloid markers such as CD2 expression in AML‐M4‐Eo with inv(16)13 and CD19 and CD56 expression in AML‐M2 with t(8:21)24,26,27 are useful in recognizing new immunophenotypic subgroups associated with these genetically defined subtypes.…”