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Published on: April 15, 2022
Immunostaining for nucleophosmin in bone marrow trephine biopsy specimens in acute myeloid leukemias
Gaia Goteri1, Antonio Zizzi, Simona Sabato
1Section of Pathological Anatomy, Department of Neurosciences, Polytechnic University of Marche Region, Ancona Hospital,Italy. g.goteri@univpm.it
Objective:
To evaluate the technicalfeasibility of nucleophosmin (NPM) staining and the problems of interpretations by pathologists in an academic regional hospital in Italy.
Study Design:
Acute myeloid leukemia (AML) is a heterogeneous clonal disorder of hematopoietic progenitor cells that presents genetic abnormalities in several genes, including NPM. Mutations of the NPM gene occur in 35% of patients with AML with normal karyotype, causing cytoplasmic rather than nuclear localization of the protein. Because the NPM antibody recently became commercially available, we immunostained a series of diagnosed AML samples. We performed NPM immunostaining in 48 AML cases. NPM immunostaining was correlated with phenotypic and cytogenetic data.
Results:
Reactivity for NPM was exclusively nuclear in 31 cases (64.6%) and nuclear and cytoplasmic in 17 cases (35.4%). The distribution of NPM cytoplasmic staining was more frequently observed in cases with monocytic differentiation and with normal karyotype or with minor cytogenetic abnormalities (p < 0.05).
Conclusion:
NPM immunostaining is a feasible test, without problems of interpretation for pathologists, when the sections are optimally prepared and can be considered predictive of peculiar phenotypic and karyotype subtypes of AML, in addition to the well-known prognostic role.
Insights
Nucleophosmin (NPM) immunostaining is a feasible diagnostic test for acute myeloid leukemia (AML). This method can predict specific AML subtypes based on cell characteristics and genetic abnormalities.
Area of Science:
- Hematology
- Oncology
- Pathology
Background:
- Acute myeloid leukemia (AML) is a complex blood disorder characterized by genetic abnormalities.
- Mutations in the nucleophosmin (NPM) gene occur in 35% of AML cases with normal karyotype, altering NPM protein localization.
- NPM protein localization (nuclear vs. cytoplasmic) is linked to AML subtypes.
Purpose of the Study:
- To assess the technical feasibility of NPM immunostaining in AML.
- To evaluate potential interpretation challenges for pathologists.
- To determine if NPM staining correlates with AML subtypes.
Main Methods:
- NPM immunostaining was performed on 48 diagnosed AML samples.
- Immunostaining results were correlated with available phenotypic and cytogenetic data.
- Analysis focused on NPM protein localization (nuclear, cytoplasmic, or both).
Main Results:
- Exclusively nuclear NPM staining was observed in 64.6% of cases.
- Nuclear and cytoplasmic NPM staining occurred in 35.4% of cases.
- Cytoplasmic NPM staining was more common in AML with monocytic differentiation and normal or minor cytogenetic abnormalities.
Conclusions:
- NPM immunostaining is technically feasible and interpretable by pathologists with optimal sample preparation.
- NPM immunostaining can predict specific phenotypic and karyotype subtypes of AML.
- NPM staining offers additional predictive value beyond its known prognostic role in AML.
