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Ali H, Puccio I, Akarca AU, Bob R, Pomplun S, Keong Wong W, Gupta R, Sekhar M, Lambert J, Al-Masri H, Stein H, Marafioti T. Megakaryocytes, erythropoietic and granulopoietic cells express CAL2 antibody in myeloproliferative neoplasms carrying CALR gene mutations. Int J Exp Pathol 2020; 102:45-50. [PMID: 32929772 PMCID: PMC7839955 DOI: 10.1111/iep.12375] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2020] [Revised: 08/02/2020] [Accepted: 08/12/2020] [Indexed: 12/31/2022] Open
Abstract
Testing for the CALR mutation is included in the updated WHO criteria for essential thrombocythaemia (ET) and primary myelofibrosis (PMF). We report on the application of the CAL2 monoclonal antibody, raised against the mutated CALR gene to myeloid cases. The immunostain was used on 116 acute myeloid leukaemias (AML) and 66 myeloproliferative neoplasms (MPN) or myelodysplastic syndromes/myeloproliferative neoplasms (MDS/MPN). None of AML cases was stained by the CAL2 antibody, while 20/66 MPNs and MDS/MPNs appeared positive. Fourteen of the latter cases were studied by molecular techniques, and all showed aberrations of the CALR gene. In addition, CAL2 positivity was found in some small‐sized elements besides megakaryocytes. By double staining, these elements corresponded to small megakaryocytes as well as both erythroid and myeloid precursors. This finding suggests possible occurrence of CALR gene abnormalities in a stem cell.
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Affiliation(s)
- Hebah Ali
- Haematological Malignancy Diagnostic Service, Leeds, UK.,University of Leeds, Leeds, UK
| | - Ignazio Puccio
- Department of Histopathology, University College London, London, UK
| | - Ayse U Akarca
- Department of Histopathology, University College London, London, UK
| | - Roshanak Bob
- Reference and Consultation Center for Lymphoma and Haematopathology, Pathodiagnostik Berlin, Berlin, Germany
| | - Sabine Pomplun
- Department of Cellular Pathology, University College Hospital, London, UK
| | - Wai Keong Wong
- Department of Haematology, University College Hospital, London, UK
| | - Rajeev Gupta
- Department of Haematology, University College Hospital, London, UK
| | - Mallika Sekhar
- Department of Haematology, University College Hospital, London, UK
| | - Jonathan Lambert
- Department of Haematology, University College Hospital, London, UK
| | | | - Harald Stein
- Reference and Consultation Center for Lymphoma and Haematopathology, Pathodiagnostik Berlin, Berlin, Germany
| | - Teresa Marafioti
- Department of Histopathology, University College London, London, UK.,Department of Cellular Pathology, University College Hospital, London, UK
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