Approximately 5-10% of chronic myeloid leukemia (CML) patients are found to have structural or numerical additional chromosomal abnormality (ACAs) in addition to the characteristic t(9;22)(q34;q11.2) BCR/ABL1 at the time of diagnosis.
The appearance of chromosomal aberrations in patients with CML BC has led to many attempts to elucidate a mechanism whereby BCR-ABL affects DNA damage and repair.
Association of cytogenetic abnormalities with detection of BCR-ABL fusion transcripts in children with T-lineage lymphoproliferative diseases (T-ALL and T-NHL).
Although the major BCR/ABL transcript is present in majority of CML patients, the minor BCR/ABL transcript is rarely reported as an additional chromosomal abnormality related to the progression of CML.
Specific subsets of MPAL are defined by chromosomal anomalies such as the t(9;22) Philadelphia chromosome BCR-ABL1 or involvement of the MLL gene on chromosome 11q23.
Specifically, it is associated to a particular cytogenetic abnormality, known as Philadelphia chromosome (Ph), which results from a fusion between part of the BCR ("breakpoint cluster region") gene from chromosome 22 and the Abelson (ABL) gene on chromosome 9 and leads to the formation a new gene leukemia-specific, the BCR-ABL.
The abnormal haemopoietic precursor cells of chronic myeloid leukaemia (CML) carry the cytogenetic abnormality [t(9;22)(q34;q11)]--a reciprocal translocation that results in the expression of a chimaeric protein derived from the fused BCR and ABL genes.
These studies involve the identification of the first cancer-associated chromosomal abnormality and the subsequent development of tyrosine kinase inhibitors (TKIs) that inhibit BCR-ABL kinase activity in CML.
Studies on CML have led to the identification of the first cancer-associated chromosomal abnormality and the subsequent development of tyrosine kinase inhibitors (TKIs) that inhibit BCR-ABL kinase activity in CML.
Thus, ectopic p185/p190 BCR-ABL expression, such as p210 BCR-ABL, PML-RARA, or C-MYC transduction, may induce an increased chromosomal instability leading to clonal karyotypic evolution, which may mimic secondary chromosome aberrations in human Ph-positive ALL.
The BCR/ABL tyrosine kinase inhibitor imatinib mesylate produces a high rate of cytogenetic responses in patients with Philadelphia (Ph)-positive chronic myeloid leukemia (CML), but secondary clonal chromosome abnormalities may develop in Ph-negative cells, and acute myeloid leukemia (AML) has been reported in patients with secondary chromosome abnormalities.
The ABL gene on chromosome band 9q34 is a proto-oncogene and is the well-known translocation partner of the BCR gene on 22q11 giving rise to t(9;22)(q34;q11), which is the hallmark of chronic myeloid leukemia and is the most common chromosomal abnormality in adult acute lymphoblastic leukemia (ALL).
Genomic instability is a hallmark of chronic myeloid leukemia in chronic phase (CML-CP) resulting in BCR-ABL1 mutations encoding resistance to tyrosine kinase inhibitors (TKIs) and/or additional chromosomal aberrations leading to disease relapse and/or malignant progression.
A BCR/ABL-negative chronic myeloid leukemia (CML) with t(12;14) (p12;q11-13) as the sole chromosomal abnormality was investigated by fluorescence in situ hybridization (FISH), which disclosed a cryptic insertion of ETV6 (previously called TEL), located at 12p12, into ABL at chromosome band 9q34.
We report a rare cryptic ins(12;9)(p13;q34q34), a chromosomal abnormality involving the ABL1 (9q34) and the ETV6 (alias TEL; 12p13) genes, detectable only by fluorescence in situ hybridization (FISH), in a patient with Philadelphia-negative chronic myeloid leukemia (CML).
Among 53 patients with a median follow-up of 16 months, of whom 38, 5 and 10 were in chronic phase, accelerated phase and blast crisis, respectively, 19 (36%) had additional chromosomal aberrations and 20 (38%) had BCR-ABL kinase domain mutations.
T-cell, MLL-rearranged, TEL-AML1-positive, E2A-PBX1-positive and hyperdiploid acute lymphoblastic leukemia, with the exception ofBCR-ABL-positive and 'B-other' acute lymphoblastic leukemias (defined as precursor B-cell acute lymphoblastic leukemia not carrying the foregoing cytogenetic aberrations), were found to have unique microRNA-signatures that differed from each other and from those of healthy hematopoietic cells.
In acute lymphoblastic leukemia, besides age and white cell count at diagnosis, the cytogenetic abnormalities t(9;22)/BCR-ABL and t(4;11)/MLL-AF4 are important prognostic markers and are often included in the treatment stratification of patients with adult acute lymphoblastic leukemia.
In both cases, multiple secondary cytogenetic abnormalities were observed at transformation, with homogeneously staining regions that were shown to contain BCR/ABL amplification by fluorescence in situ hybridization appearing after imatinib mesylate administration.
In the present case, cytogenetic and fluorescence in situ hybridization analyses revealed multiple chromosomal aberrations, including a del(9)(q21qter) and a marker chromosome ish der(9)(ABL+).
The translocation t(9;22)(q34;q11), known as Philadelphia chromosome (Ph1) or its molecular equivalent the expression of BCR-ABL-mRNA, is one of the most striking and well-characterized cytogenetic abnormalities in leukemia.
The effect of the additional cytogenetic abnormalities on major molecular response and BCR-ABL kinase domain mutations in long-term follow-up chronic myeloid leukemia patients, a cross sectional study.