Clinical, Immunophenotypic, and Genomic Findings of Acute Myeloid Leukemia With RAM Immunophenotype: Comparison With Other CD56-Positive Acute Leukemias

Authors

• Hanan Hamdan, Department of Pathology University of Texas Southwestern Medical Center Dallas Texas USA.
• Yen-Chun Liu, Department of Pathology St. Jude Children's Research Hospital Memphis Tennessee USA.
• Sa A. Wang, Department of Hematopathology, Division of Pathology/Lab Medicine The University of Texas MD Anderson Cancer Center Houston Texas USA.
• Jacob Bledsoe, Department of Pathology Boston Children's Hospital (BCH) Boston Massachusetts USA.
• Karen M. Chisholm, Department of Pathology Seattle Children's Hospital Seattle Washington USA.
• Alexa Siddon, Department of Pathology Yale School of Medicine New Haven Connecticut USA.
• Robert Ohgami, Department of Pathology University of Utah and ARUP Laboratories Salt Lake City Utah USA.
• Tracy I. George, Stanford Health Care Stanford Medicine Children's Health Stanford California USA.
• Jason Kurzer, Department of Pathology Massachusetts General Hospital Boston Massachusetts USA.
• Robert P. Hasserjian, Department of Pathology The University of Chicago Chicago Illinois USA.
• Daniel A. Arber, Division of Hematopathology Hospital of the University of Pennsylvania Philadelphia Pennsylvania USA.
• Adam Bagg, Division of Hematopathology Hospital of the University of Pennsylvania Philadelphia Pennsylvania USA.
• Kathryn Foucar, Department of Hematopathology The University of New Mexico Albuquerque New Mexico USA.
• Elizabeth Margolskee, Department of Pathology The Children's Hospital of Philadelphia Philadelphia Pennsylvania USA.
• Dorottya Laczko, Perelman School of Medicine. Department of Pathology University of Pennsylvania Philadelphia Pennsylvania USA.
• Weina Chen, Department of Pathology University of Texas Southwestern Medical Center Dallas Texas USA.
• Franklin Fuda, Department of Pathology University of Texas Southwestern Medical Center Dallas Texas USA.
• Nidhi Aggarwal, Department of Pathology UPMC Presbyterian Hospital Pittsburgh Pennsylvania USA.
• Olga K. Weinberg, Department of Pathology University of Texas Southwestern Medical Center Dallas Texas USA.

Document Type

Article

Publication Date

2-1-2025

Abstract

BACKGROUND: Acute myeloid leukemia (AML) with RAM immunophenotype is a newly recognized high-risk AML immunophenotypic subcategory characterized by blasts with bright expression of CD56 and weak to absent expression of CD45, HLA-DR, and CD38, as first described by the Children's Oncology Group (COG). The relationship between AML-RAM and other CD56-positive acute leukemias is unclear. The goal of this study is to characterize the clinicopathological characteristics of AML with RAM phenotype and compare them with other CD56 co-expressing acute leukemias.

METHODS: From a multi-institutional search, we identified a total of 160 CD56+ acute leukemia cases, including AML-RAM (

RESULTS: AML-RAM patients were significantly younger and presented with significantly higher platelet and white blood cell counts and bone marrow (BM) blast percentages when compared to AUL (

CONCLUSION: We find that AML with RAM phenotype occurs primarily in younger ages, with distinct clinicopathological, immunophenotypic, and mutational presentations, and worse prognosis. This diagnosis should be considered in the clinical differential diagnosis of CD56-positive acute leukemias.

Recommended Citation

Hamdan H, Liu YC, Wang SA, Bledsoe J, Chisholm KM, Siddon A, Ohgami R, George TI, Kurzer J, Hasserjian RP, Arber DA, Bagg A, Foucar K, Margolskee E, Laczko D, Chen W, Fuda F, Aggarwal N, Weinberg OK. Clinical, immunophenotypic, and genomic findings of acute myeloid leukemia with RAM immunophenotype: Comparison with other CD56-positive acute leukemias. EJHaem. 2024 Dec 16;6(1):e1052. doi: 10.1002/jha2.1052. PMID: 39866946; PMCID: PMC11756974.