NG2 Molecule Expression in Acute Lymphoblastic Leukemia B Cells: A Flow-Cytometric Marker for the Rapid Identification of KMT2A Gene Rearrangements

• Published in: Mediterranean journal of hematology and infectious diseases 2024, Vol.16 (1), p.e2024018-e2024018
• Main Authors: Bisegna, Maria Laura, Peragine, Nadia, Elia, Loredana, Matarazzo, Mabel, Milani, Maria Laura, Intoppa, Stefania, Di Trani, Mariangela, Malfona, Francesco, Martelli, Maurizio, De Propris, Maria Stefania
• Format: Article
• Language: English
• Subjects: acute lymphoblastic leukemia; flow-cytometry; KMT2A gene rearrangements; NG2; Original
• ISSN: 2035-3006; 2035-3006
• DOI: 10.4084/MJHID.2024.018

B-lineage acute lymphoblastic leukemias (B-ALL) harboring rearrangements of the histone lysine [K]-Methyltransferase 2A ( ) gene on chromosome 11q23 ( ) represent a category with dismal prognosis. The prompt identification of these cases represents an urgent clinical need. Considering the correlation between rat neuron glial-antigen 2 (NG2) chondroitin-sulfate-proteoglycan molecule expression and , we aimed to identify an optimized cytofluorimetric diagnostic panel to predict the presence of . We evaluated 88 NG2+ B-ALL cases identified with an NG2 positivity threshold >10% from a cohort of 1382 newly diagnosed B-ALLs referred to the Division of Hematology of 'Sapienza' University of Rome. Eighty-five of 88 (96.6%) NG2+ B-ALLs harbored and were mainly pro-B ALL (77/85; 91%). Only 2 B-ALLs with showed NG2 expression below 10%, probably due to the steroid therapy administered prior to cytofluorimetric analysis.Compared to cases, B-ALLs showed a higher blast percentage, significantly higher mean fluorescence intensity (MFI) of CD45, CD38, and CD58, and significantly lower MFI of CD34, CD22, TdT, and CD123.The study confirmed differences in CD45, CD34, CD22, and TdT MFI within the same immunologic EGIL group (European Group for the immunological classification of leukemias), indicating no influence of the B-ALLs EGIL subtype on the B-ALLs immunophenotype. Our data demonstrate the association between NG2 and in B-ALLs identify a distinctive immunophenotypic pattern, useful for rapid identification in diagnostic routines of these subtypes of B-ALLs with a poor prognosis that benefits from a specific therapeutic approach.