IGH/FGFR3 translocation, t(4;14)(p16;q32) The t(4;14) translocation is associated with upregulation of the fibroblast growth factor receptor 3 (FGFR3) and the myeloma SET domain protein. This reciprocal translocation is a common alteration in multiple myeloma (MM) not often detected by classic cytogenetics, because of the telomeric location of the regions involved. Patients with t(4;14) demonstrate an […]
Loss of ATM gene, del(11q22.3) The protein kinase ATM (Ataxia-Telangiectasia Mutated) gene located in 11q22.3 is frequently deleted in cases of CLL. The ATM gene is an important checkpoint gene involved in cell damage management. Its function is to assess the level of DNA damage that the cell has received and attempt to repair the DNA
IGH/MYC translocation, t(8;14) Translocation t(8;14)(q24;q32), IGH-MYC, is the cytogenetic hallmark of Burkitt’s lymphoma, but also found in rare occasions, in cases of B-cell lymphoma or chronic lymphocytic leukemia (CLL). This translocation results in a fusion gene that deregulates and overexpressee MYC. FISH is very useful in understanding these complex chromosomal abnormalities and their relationship to other
IGH rearrangements, (14q32) There are a number of stereotypical translocations involved in IGH (14q32) rearrangements associated with lymphoblastic leukemias. In B-ALL, IGH is most notably involved in rearrangements involving the cMYC oncogene as a result of the t(8;14) translocation. However, less common rearrangements of the IGH gene are most often seen in T-ALL, but can also be found in B-ALL (0.1% of the
TCF3-PBX1 fusion gene, t(1;19) t(1;19)(q23;p13) translocation event between the TCF3 locus (19p13.3) and PBX1 locus (1q23) which produces the chimeric gene TCF3-PBX1, is present in most type L1 and type L2 ALLs and exceptionally in ALL- L3. The translocation occurs in approximately 5% of childhood ALL and while this chromosomal anomaly usually was associated with poor prognosis, nowadays associates with
ABL-BCR translocation, t(9;22) The t(9;22)(q34;q11.2) translocation fuses ABL proto-oncogene on chromosome 9 with the BCR (breakpoint cluster region) region located on chromosome 22, leading to the formation of the Philadelphia chromosome (Ph) and the formation of two hybrid genes. The first gene is BCR-ABL (major), located on the long arm of chromosome 22 or chromosome
TEL/ETV6-AML1/RUNX1 fusion gene, t(12;21) t(12;21)(p13;q22) reciprocal translocation is the most frequent chromosomal rearrangement in childhood B-ALL with an incidence of 25% in children (only 3% occurs in adults). The expression of the resulting fusion gene TEL-AML1 or ETV6-RUNX1, leads to expansion of the precursors of B cells giving them a great capacity for self-renewal and differentiation to mature
12;21 – TEL(ETV6)-AML1(RUNX1) Read More »
MLL rearrangements, (11q23) MLL/ALL1/HRX gene (11q23) encodes a 90 amino acid protein and is highly expressed in the thymus, but not in peripheral lymphoid tissues. In contrast to its restricted normal hematopoietic tissue distribution, this gene is expressed in all leukemia cell lines studied. Chromosomal rearrangements of the human MLL gene are associated with acute leukemias
