ETV6-ABL1 fusion is a rare but recurrent genetic aberration found in various hematologic malignancies involving both the lymphoid and myeloid lineage, but to the best of our knowledge, CMML is an exceptionally rare presentation of ETV6-ABL1 rearranged neoplasm.
The introduction of BCR-ABL-tyrosine kinase inhibitors (TKI) for treatment of hematologic malignancies has made a significant impact on patient outcome.
In this work we demonstrate for the first time that in CML the BMI1 protein is co-expressed with BCR-ABL1 only in the cytoplasm of the CD26+ precursors; on the contrary, in other hematological malignancies where BMI1 is commonly expressed (follicular lymphoma, essential thrombocytemia, acute myeloid leukemia), it was not co-localized with CD26 or, obviously, with BCR-ABL1.
BCR-ABL1-targeting tyrosine kinase inhibitors (TKIs) have revolutionized treatment of Philadelphia chromosome-positive (Ph<sup>+</sup>) hematologic neoplasms.
To characterize the incidence, clinical features and genetics of ETV6-ABL1 leukemias, representing targetable kinase-activating lesions, we analyzed 44 new and published cases of ETV6-ABL1-positive hematologic malignancies [22 cases of acute lymphoblastic leukemia (13 children, 9 adults) and 22 myeloid malignancies (18 myeloproliferative neoplasms, 4 acute myeloid leukemias)].
Among these, a very rare fusion transcript joining the first 6 exons of BCR to exon 2 of ABL1 (e6a2) has been reported in various hematological malignancies characterized by an aggressive clinical course.
Although nuclear ABL1 triggers cell death through its interaction with the Hippo pathway coactivator YAP1 in normal cells, we show that low YAP1 levels prevent nuclear ABL1-induced apoptosis in these hematologic malignancies.
Chronic myeloid leukemia (CML) is a hematological malignancy that arises from the transformation of stem hematopoietic cells by the fusion oncogene BCR/ABL and subsequent clonal expansion of BCR/ABL-positive progenitor leukemic cells.
The presence of the type A fusion transcript strongly implies ALL manifestation in ETV6/ABL1-positive hematologic malignancies as minor BCR breakpoint in BCR/ABL1-positive ALL.
Collectively our data show that monitoring Hh pathway activity contemporaneously with BCR-ABL1 mRNA level may improve the chance of early detection of patients who will experience a relapse (mainly in the high Sokal risk group), paving the way for an innovative management of this hematologic malignancy.
Only 19 cases of ETV6/ABL1-positive hematological malignancy have been published, diagnosed with chronic myeloid leukemia, other types of chronic myeloproliferative neoplasm, acute myeloid leukemia or acute lymphoblastic leukemia (ALL).
Chronic myelogenous leukemia (CML) is a hematological malignancy that begins as indolent chronic phase (CP) but inevitably progresses to fatal blast crisis (BC). p210BCR/ABL, a chimeric protein with enhanced kinase activity, initiates CML CP, and additional genetic alterations account for progression to BC, but the precise mechanisms underlying disease evolution are not fully understood.
The discovery of the BCR-ABL fusion gene on the Philadelphia (Ph) chromosome in 1985 was the start of a new era in understanding the molecular basis of hematologic malignancies.
The identification of the Philadelphia chromosome and the subsequent discovery that it represents a translocation between the long arms of chromosomes 9 and 22 producing an aberrant tyrosine kinase, known as BCR-ABL1, has catalyzed our understanding and treatment of this hematologic malignancy.
Both myelodysplastic syndrome and BCR/ABL-negative classic MPD were previously discussed as part of the current ongoing symposium on hematological malignancies.
The role of fluorescence in situ hybridization (FISH) for monitoring hematologic malignancies with BCR/ABL or ETO/AML1 rearrangement: a comparative study with FISH and G-banding on 919 consecutive specimens of hematologic malignancies.
However, several lines of evidence suggest that also quantitative changes of the BCR/ABL transcript amounts could explain the progression of the leukemic phenotype in the BCR/ABL-positive hematologic malignancies.
Expression of the P210bcr/abl gene in mice gives rise to a spectrum of hematological malignancies, most prominently a myeloproliferative syndrome which closely resembles human chronic myelogenous leukemia (CML).