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

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