Assessment of myeloid and monocytic dysplasia by flow cytometry in de novo AML helps define an AML with myelodysplasia-related changes category

The International Consensus Classification of acute myeloid leukemia

Acute myeloid leukemias (AMLs) are overlapping hematological neoplasms associated with rapid onset, progressive, and frequently chemo-resistant disease. At diagnosis, classification and risk stratification are critical for treatment decisions. A group with expertise in the clinical, pathologic, and genetic aspects of these disorders developed the International Consensus Classification (ICC) of acute leukemias. One of the major changes includes elimination of AML with myelodysplasia-related changes group, while creating new categories of AML with myelodysplasia-related cytogenetic abnormalities, AML with myelodysplasia-related gene mutations, and AML with mutated TP53. Most of recurrent genetic abnormalities, including mutations in NPM1, that define specific subtypes of AML have a lower requirement of ≥ 10% blasts in the bone marrow or blood, and a new category of MDS/AML is created for other case types with 10-19% blasts. Prior therapy, antecedent myeloid neoplasms or underlying germline genetic disorders predisposing to the development of AML are now recommended as qualifiers to the initial diagnosis of AML. With these changes, classification of AML is updated to include evolving genetic, clinical, and morphologic findings.

Diagnosis and Treatment of Patients With Acute Myeloid Leukemia With Myelodysplasia-Related Changes (AML-MRC)

Objectives

Acute myeloid leukemia (AML) with myelodysplasia-related changes (AML-MRC) represents a high-risk and somewhat diverse subtype of AML, and substantial confusion exists about the pathologic evaluation needed for diagnosis, which can include the patient’s clinical history, cytogenetic analysis, mutational analysis, and/or morphologic evaluation. Treatment decisions based on incomplete or untimely pathology reports may result in the suboptimal treatment of patients with AML-MRC.

Methods

Using a PubMed search, diagnosis of and treatment options for AML-MRC were investigated.

Results

This article reviews the current diagnostic criteria for AML-MRC, provides guidance on assessments necessary for an AML-MRC diagnosis, summarizes clinical and prognostic features of AML-MRC, and discusses potential therapies for patients with AML-MRC. In addition to conventional chemotherapy, treatment options include CPX-351, a liposomal encapsulation of daunorubicin/cytarabine approved for treatment of adults with AML-MRC; targeted agents for patients with certain mutations/disease characteristics; and lower-intensity therapies for less fit patients.

Conclusions

Given the evolving and complex treatment landscape and the high-risk nature of the AML-MRC population, a clear understanding of the pathology information necessary for AML-MRC diagnosis has become increasingly important to help guide treatment decisions and thereby improve patient outcomes.

Immunophenotypic dysplasia and aberrant T-cell antigen expression in acute myeloid leukaemia with complex karyotype and TP53 mutations

AIMS

Cytogenetic and molecular aberrations are the strongest factors in determining outcome in acute myeloid leukaemia (AML). AML with complex karyotype confers a particularly poor prognosis and is associated with morphologic dysplasia. Flow cytometric immunophenotyping (FCI) has been investigated in defining dysplasia within myelodysplastic syndromes, but little is known about immunophenotypic dysplasia in AML and correlation with genetic abnormalities. This study aimed to explore differences in antigen expression by FCI in AML with complex karyotype (AML-CK) and AML with complex karyotype and TP53 mutations (AML-TP53) compared with AML with normal karyotype (AML-NK).

METHODS

Twenty-five cases of AML-CK, 13 of which had abnormalities of TP53, were compared with 83 cases of AML-NK using FCI.

RESULTS

Our findings demonstrated brighter expression of CD34 with decreased CD33 and aberrant expression of CD5 in blasts of AML-CK, while AML-TP53 blasts exhibited brighter expression of CD13. Granulocytes in AML-CK exhibited brighter expression of CD5, CD7, CD10 and CD14, with brighter CD3 also seen in AML-TP53.

CONCLUSIONS

Our results suggest that immunophenotypic dysplasia correlates with complex karyotype and TP53 mutation, including increased expression of T-cell antigens.