BCR/ABL1 fluorescence <em>in situ</em> hybridization fusion signals on both copies of chromosome 22 in a Philadelphia-masked chronic myeloid leukemia case: implication for the therapy

• Main Authors: Silvia Soriani, Valentina Guido, Giambattista Bertani, Clara Cesana, Valentina Motta, Gabriella De Canal, Elena De Paoli, Silvio Veronese, Emanuela Bonoldi, Lorenza Romitti
• Format: Article
• Language: English
• Published: PAGEPress Publications 2021-03-01
• Series: Hematology Reports
• Subjects: Chronic Myeloid Leukemia; CML; Philadelphia chromosome-negative; masked Philadelphia; p.(Tyr315Ile) mutation
• Online Access: https://www.pagepress.org/journals/index.php/hr/article/view/8795
• ISSN: 2038-8322; 2038-8330

The cytogenetic hallmark of Chronic Myeloid Leukemia (CML) is the presence of Philadelphia (Ph) chromosome, which results from a reciprocal translocation t(9;22)(q34;q11). In this report, we describe a CML patient with no evidence of Ph chromosome but trisomy of chromosome 8 as single cytogenetic abnormality and a typical e14a2 (b3a2) BCR-ABL1 fusion transcript. Fluorescence In Situ Hybridization (FISH) analysis revealed an uncommon signal pattern: the fusion signals were located on both copies of chromosome 22. During the course of the disease the appearance of the p.(Tyr315Ile) mutation was recorded. To the best of our knowledge this is the first Ph chromosome-negative CML case with e14a2 (b3a2) BCR-ABL1 transcript and p.(Tyr315Ile) mutation.