An e6a2 BCR-ABL fusion transcript in a CML patient having an iliac chloroma at initial presentation

A double Philadelphia chromosome-positive chronic myeloid leukemia patient, co-expressing P210BCR-ABL1 and P195BCR-ABL1 isoforms

“…P195 BCR-ABL1 has been described in a few CML patients and linked to a poor clinical outcome due to the aggressive progression. [3][4][5][6][7] The genetic instability of BCR-ABL1 expressing blast cells may lead to additional cytogenetic aberrations (ACAs), such as double Ph, trisomy 8, and i(17)(q10). These are known to reduce the response to imatinib and are detected in less than 5% of CML patients at diagnosis.…”

Thoracic t(9;22)-Positive Granulocytic Sarcoma as Initial Presentation of Chronic Myeloid Leukemia

“…Most patients presenting with aleukemic GS progress to a leukemic phase within 1 year of diagnosis. 11 The initial manifestation of relapse after alloBMT for patients with AML can be in the form of GS. It can also occur, although even more rarely, in patients with other myeloid neoplasms, such as myelodysplastic syndrome, myeloproliferative disorders, or CML.…”

Chronic Myelogenous Leukemia with the e6a2 <i>BCR-ABL</i> and Lacking Imatinib Response: Presentation of Two Cases

“…After allo-SCT, they developed extramedullary disease. Among 6 imatinib-treated e6a2 BCR-ABL CML patients reported before, 3 (50%) relapsed or did not respond [4, 5, 14]. Two of them additionally developed imatinib resistance [5, 14] and 1 extramedullary disease [14].…”

“…In rare instances, the BCR breakpoint occurs in intron 1 (minor BCR ), giving rise to the shorter e1a2 BCR-ABL transcript, which is typically seen in the more aggressive acute lymphatic leukemia [3]. Sporadic CML patients have BCR-ABL transcripts resulting from breakpoints outside major and minor BCR (e6a2, e8a2, e19a2) [4,5,6,7,8,9,10,11,12,13,14]. A small group of CML patients (less than 5%) are Philadelphia chromosome negative despite the presence of a BCR-ABL transcript.…”