Translocation (5;10)(q22;q24) in a case of acute lymphoblastic leukemia.

The activation of genes important to acute lymphoblastic leukemia (ALL) may be evidenced by somatically acquired chromosomal translocations found recurrently in different patient subgroups. It is for this reason that research efforts have focused on the molecular dissection of recurring chromosomal rearrangements. However, even though a large number of leukemia-causing genes have been identified, the genetic basis of many ALL cases remains unknown.

A full-length and potentially active LINE element is integrated polymorphically within the IGL locus in a genomically unstable region of chromosome 22.

Leukemic cells of a patient diagnosed with chronic myeloid leukemia (CML) showed a complex BCR-ABL1 rearrangement hidden within a normal appearing karyotype. Previous molecular studies had established that the 3' BCR had recombined at a novel site within the variable region of the immunoglobulin lambda locus ( IGL). A segment of DNA mapping very close to the site of the IGL/3' BCR recombination recognized a previously undescribed insertion polymorphism.

3' BCR recombines with IGL locus in BCR-ABL-positive philadelphia-negative chronic myeloid leukemia.

We have isolated the 3' BCR breakpoint junction of a complex BCR-ABL1 rearrangement found in leukemic cells with a cytogenetically normal karyotype, and the corresponding germline fragment that spanned the 3' BCR recombination site. Fluorescence in situ hybridization localized the 3' BCR recombination site to 22q11, about 350-600 kb proximal to BCR. Restriction map and DNA sequence comparisons indicated that 3' M-Bcr had recombined at a site within the variable region (Itv Region IV) of the immunoglobulin lambda (IGL) locus.

The BCR gene recombines preferentially with Alu elements in complex BCR-ABL translocations of chronic myeloid leukaemia.

Chronic myeloid leukaemia (CML) develops when two genes, BCR on chromosome 22 and ABL on chromosome 9, recombine to form a hybrid BCR-ABL gene with leukaemogenic properties. The mechanism which underlies this recombination is unknown, but additional chromosome sites may be involved to form complex BCR-ABL rearrangements. The majority of breakpoints in BCR occur within a 5 kb major breakpoint cluster region, M-Bcr.

Spatial organization of ABR and CRK genes on human chromosome band 17p13.3.

Deletion of part or all of chromosome 17p is among the most frequent chromosome abnormalities in human cancer. We show that the CRK and ABR genes are close to a marker on chromosome 17p13.3, D17S34, which is frequently deleted in different tumours, and demonstrate that CRK is centromeric to ABR.

Deletion 20q in association with Philadelphia chromosome positive acute lymphoblastic leukemia. A report of two cases.

Cytogenetic deletions involving the long arm of chromosome 20 are thought to be characteristic of myeloid disorders. We report clinical and cytogenetic observations of two adult patients with Philadelphia chromosome positive acute lymphoblastic leukemia: one with a smaller 20q deletion that was the sole cytogenetic abnormality in a persisting remission clone, the other with a larger 20q deletion that was a late addition to the leukemic clone at disease relapse following allogeneic bone marrow transplantation.

CRK proto-oncogene maps to human chromosome band 17p13.

A genomic DNA fragment, isolated from a human phage library using a chicken crk cDNA probe, was shown to derive from the human CRK locus. We have used fluorescent in situ hybridization (FISH) to map CRK distal in chromosome band 17p13, a region which demonstrates frequent deletion or loss of heterozygosity in a wide range of human cancers.

Oligoclonal B-cell leukemia characterized by spontaneous cell division and telomere association.

Cytogenetic analysis of unstimulated cultures from a female patient with chronic B-cell leukemia (CLL) revealed three cytogenetically distinct clones, suggesting that the patient's leukemia was oligoclonal. Immunoglobulin heavy chain gene rearrangement studies revealed 1 germline and 4 rearranged bands, indicative of an oligoclonal leukemic population. Further evidence of oligoclonality was provided by X-linked RFLP studies.

Complex karyotypic evolution in B-cell chronic lymphocytic leukemia.

Cytogenetic analysis at diagnosis in a female patient with chronic B-cell leukemia showed a single abnormal clone with a 4p+ abnormality, 46,XX, -4, +der(4)t(4;?)(p16;?). Six additional clones evolved from this clone during the following 4 1/2 years and showed 3p+, 4p-, and 11q- chromosomes in addition to the 4p+ abnormality. Immunoglobulin heavy chain gene rearrangement studies showed two rearranged bands and a faint germline band.

Molecular definition of interstitial deletions of chromosome 13 in leukemic cells.

Three patients with leukemia and one with a myeloproliferative disorder carried an interstitial deletion of chromosome 13, del(13)(q12q14), in leukemic cells. Proximal and distal breakpoints of the deleted segment were characterized by using DNA restriction fragment length polymorphisms of chromosome 13 supplemented by quantitative densitometry of hybridization signals to determine the copy number of individual loci. Both proximal and distal breakpoints varied between patients, and it is unlikely that a significant hybrid gene was formed by rejoining at the breakpoint junctions.