The chromosome translocation (11;14)(p13;q11) associated with T-cell acute lymphocytic leukemia: an 11p13 breakpoint cluster region

The translocation (11;14)(p13;q11) was observed in karyotypes of leukemic cells from a 3-year-old boy with T-cell acute lymphocytic leukemia (T-ALL). Since this translocation is a recurrent marker of T-ALL, we undertook to investigate its mode of formation and role in leukemogenesis. The cytogenetic breakpoint on chromosome 14 occurs in 14q11, the same band wherein lies the T-cell receptor alpha/delta chain gene; and Southern hybridization analysis of peripheral blood and bone marrow DNA uncovered a tumor-specific rearrangement in the D delta-J delta region of this locus. DNA encompassing the rearrangement was isolated by molecular cloning, and further analysis revealed it to be the t(11;14)(p13;q11) junction. Nucleotide sequence determination of the junction indicates that the 14q11 breakpoint occurs immediately adjacent to the D delta 2 gene segment. Hence, the translocation arose as an aberrant rearrangement between the downstream recombination signal of D delta 2 and a pseudo recombination signal adjacent to the chromosome 11 breakpoint. Finally, comparison of the breakpoint in band 11p13 with those of other translocations (11;14)(p13;q11) identified a breakpoint cluster region of approximately 1.2 kilobase-pairs (kb), alterations of which may promote the development of T-ALL.     

T-cell receptor delta gene rearrangement in childhood T-cell acute lymphoblastic leukemia

During the development of functional T lymphocytes, a variety of genes involved in antigen recognition undergo somatic rearrangement. These include the alpha, beta, and gamma chain genes. Recently a fourth rearranging gene, the delta chain gene, embedded in the alpha chain locus, has been described. We have determined the structure of the beta, gamma, and delta chain genes in 15 cases of T-cell acute lymphoblastic leukemia (T-ALL) representing stage I (CD7+, CD1-, CD3-) and stage II (CD7+, CD1+, CD3-) of intrathymic T-cell development. The alpha-delta locus was rearranged in 14 of the 15 cases. In three cases the delta constant region was deleted on both chromosomes, suggesting biallelic V-J alpha rearrangement. A limited pattern of rearrangement of the delta locus was observed in the remaining 11 cases. When the alpha-delta region was rearranged, there was rearrangement of the beta and gamma TcR in all cases except two; in these cases the beta chain was in the germline configuration. These findings support the hypothesis that delta chain gene rearrangement is an early event in T- cell development, possibly contemporary to gamma gene rearrangement, and that the delta locus has a limited repertoire.     

Clustering of breakpoints on chromosome 10 in acute T-cell leukemias with the t(10;14) chromosome translocation.

The T-cell receptor (TCR) alpha/delta chain locus on chromosome 14q11 is nonrandomly involved in translocations and inversions in human T-cell neoplasms. We have analyzed three acute T-lymphoblastic leukemia samples carrying a t(10;14)(q24;q11) chromosome translocation by means of somatic cell hybrids and molecular cloning. In all cases studied the translocation splits the TCR delta chain locus. Somatic cell hybrids containing the human 10q+ chromosome resulting from the translocation retain the human terminal deoxynucleotidyltransferase gene mapped at 10q23-q24 and the diversity and joining, D delta 2-J delta 1, regions of the TCR delta chain, but not the V alpha region (variable region of the TCR alpha chain), demonstrating that the split occurred within the V alpha-D delta 2 region. Molecular cloning of the breakpoint junctions revealed that the TCR delta chain sequences involved are made from the D delta 2 segment. The chromosome breakpoints are clustered within a region of approximately 263 base pairs of chromosome 10. The results suggest that the translocation of the TCR delta chain locus to a locus on 10q, which we have designated TCL3, results in deregulation of this putative oncogene, leading to acute T-cell leukemia.     

Juxtaposition of the T-cell receptor alpha-chain locus (14q11) and a region (14q32) of potential importance in leukemogenesis by a 14;14 translocation in a patient with T-cell chronic lymphocytic leukemia and ataxia-telangiectasia.

We describe a t(14;14)(q11;q32) translocation in a patient with T-cell chronic lymphocytic leukemia and ataxia-telangiectasia (AT). By using a battery of joining (J)-segment probes from the T-cell receptor (TCR) alpha-chain locus TCRA, three distinct J alpha rearrangements were observed. One rearrangement reflected a normal TCRA variable (V) region V alpha-to-J alpha recombination. The second rearrangement was caused by the translocation even itself, which joined a DNA segment from 14q32 centromeric to the immunoglobulin heavy chain locus (IGH) and a J alpha gene located approximately 75 kilobases (kb) 5' of the TCRA constant region gene (C alpha). A third rearrangement involved a 17-kb internal deletion 3' to the translocation, a rearrangement within the J alpha locus that has been observed once before in a patient with AT. Analysis of these three rearrangements underscores the increase in aberrant locus-specific recombination in lymphocytes from patients with AT. Furthermore, these studies support the view that a growth-effecting gene is present in the 14q32 region that participates in the leukemogenic process.     

Chromosomal abnormalities in T-cell large granular lymphocyte leukaemia: report of two cases and review of the literature

Cytogenetic information on T-cell large granular lymphocyte leukaemia (T-LGL; large granular lymphocytosis) is limited. We report two cases of T-LGL with unusual karyotypic aberrations. The first case showed a novel inv(7)(p15q22) as the sole chromosomal abnormality, while the second case showed an inv(14)(q11q32) with evidence of clonal evolution. The breakpoints 7p14-p15 and 14q11 coincide with the T-cell receptor (TCR)-gamma and TCR-alpha/TCR-delta gene loci respectively. This is the first report describing the possible involvement of T-cell receptor genes in karyotypic aberrations in T-LGL.     

c-tal, a helix-loop-helix protein, is juxtaposed to the T-cell receptor- beta chain gene by a reciprocal chromosomal translocation: t(1;7)(p32;q35)

Studies on nonrandom chromosomal translocations have been important for the identification of genes potentially involved in the malignant transformation of cells. The most widely studied translocations, involving members of the Ig supergene family, have shown juxtapositions of proto-oncogenes with the rearranging loci. Such translocations can inappropriately activate expression of the proto-oncogenes and thereby play a role in tumorigenesis. Because the cytogenetic analysis of a bone marrow sample from a child with T-cell acute lymphoblastic leukemia showed a (1;7)(p32;q35) translocation, we sought to determine if the translocation breakpoint was in the T-cell receptor (TCR)-beta gene locus on chromosome 7. Analysis of the TCR-beta gene by Southern blotting showed three rearranged bands. Nucleotide sequencing and Southern blot analysis of TCR-beta genomic clones, isolated from patient DNA, showed that one contained a normal rearrangement of the TCR-beta gene using V beta 12.2, D beta 2.1, and J beta 2.5, whereas two other clones contained DNA from derivative chromosomes 1 and 7. Chromosomal mapping showed that the (1;7) translocation breakpoint was 35 kb 3' to the c-tal gene locus. The juxtaposition of c-tal to the TCR- beta locus may enhance c-tal expression and contribute to T-cell leukemogenesis.     

Comparative genomic hybridization analysis in adult T-cell leukemia/lymphoma: correlation with clinical course

Sixty-four patients with adult T-cell leukemia/lymphoma (ATL; 18 patients with indolent subtype and 46 with aggressive subtype) associated with human T-lymphotropic virus type 1 (HTLV-1) were analyzed using comparative genomic hybridization (CGH). The most frequent observations were gains at chromosomes 14q, 7q, and 3p and losses at chromosomes 6q and 13q. Chromosome imbalances, losses, and gains were more frequently observed in aggressive ATL than in indolent ATL, with significant differences between the 2 ATL subtypes at gains of 1q and 4q. An increased number of chromosomal imbalances was associated with a significantly shorter survival in all patients. A high number of chromosomal losses was associated with a poor prognosis in indolent ATL, whereas the presence of 7q+ was marginally associated with a good prognosis in aggressive ATL. Paired samples (ie, samples obtained at different sites from 4 patients) and sequential samples from 13 patients (from 6 during both chronic disease and acute crisis and from 7 during both acute onset and relapse) were examined by CGH and Southern blotting for HTLV-1. All but 2 paired samples showed differences on CGH assessment. Two chronic/crisis samples showed distinct results regarding both CGH and HTLV-1 integration sites, indicating clonal changes in ATL at crisis. In 11 patients, the finding of identical HTLV-1 sites and clonally related CGH results suggested a common origin of sequential samples. In contrast to chronic/crisis samples, CGH results with all acute/relapse sample pairs showed the presence of clonally related but not evolutional subclones at relapse, thereby suggesting marked chromosomal instability. In summary, clonal diversity is common during progression of ATL, and CGH alterations are associated with clinical course. (Blood. 2001;97:3875-3881)     

The t(1;14)(p34;q11) is nonrandom and restricted to T-cell acute lymphoblastic leukemia: a Pediatric Oncology Group study

We report the nonrandom occurrence, frequency, and degree of immunophenotype association of the t(1;14)(p34;q11) in children with acute lymphoblastic leukemia (ALL). This chromosomal abnormality occurred in leukemia cells from 5 of 1,630 (0.3%) consecutive children with newly diagnosed ALL who were entered on a single Pediatric Oncology Group classification study (POG 8600) between January 1986 and February 1989. The frequency of the t(1;14) was 3% (5 of 168 cases) in children with T-cell ALL. All five cases had pseudodiploid karyotypes, and in 3 cases the t(1;14) was accompanied by a deletion of the long arm of chromosome 6. This translocation is of special interest because the breakpoint on chromosome 14 in band q11 corresponds to the assigned locus of the T-cell receptor alpha/delta chain gene. All five of our patients and three cases reported previously have had T-cell ALL. These findings, considered together, suggest that this translocation is specific for T-cell ALL and that a gene in the 1p34 region may play an important role in malignant transformation of thymocytes.     

Analysis of a T-cell tumor-specific breakpoint cluster at human chromosome 14q32.

Cytogenetic abnormalities involving chromosome 14 band q32 are consistently observed in human T-cell tumors. Patients with ataxia-telangiectasia (AT) are especially prone to development of these tumors, which frequently carry either inversion inv(14)(q11;q32) or translocation t(14;14) (q11;q32) chromosomes. We have previously shown that the cytogenetic breakpoints of one t(14;14)(q11;q32) chromosome and two inv(14)(q11;q32) chromosomes in T-cell tumors from AT and non-AT patients join the T-cell receptor alpha chain locus, at chromosome band 14q11, with a region(s) at 14q32 centromeric of the immunoglobulin heavy chain variable region (VH) gene IGHV. We now show that these two inv(14) breakpoints are linked by 2.1 kb of germ-line 14q32 DNA and that the three breakpoints define, by in situ hybridization analysis, a single locus at chromosome band 14q32.1 located about 15-20 million base pairs on the centromeric side of the IGH locus. Sequence analysis of the 14q32.1 breakpoint regions indicates that abnormal recombination does not universally result from mistaken V-D-J joining (D = diversity region; J = joining region). Therefore, we invoke a tumor selection model to describe the role of the 14q32.1 locus in tumor development.     

The T-cell receptor delta chain locus is disrupted in the T-ALL associated t(11;14)(p13;q11) translocation

Two T-ALL patients carrying a t(11;14)(p13;q11) translocation were analyzed. Southern blotting experiments demonstrated that both patients had rearranged their J delta genes and that the translocation involved the delta locus in both cases. In one patient, cloning, restriction mapping, and sequencing showed that the translocation occurred on a D delta 1-D delta 2-J delta 2 rearranged gene. In addition, the rearrangement on chromosome 11 occurred in both patients within a segment of less than or equal to 2 kb showing the presence in this region of a point of recurrent recombination.     

Molecular analysis of a t(14;14) translocation in leukemic T-cells of an ataxia telangiectasia patient.

We have detected and cloned two rearrangements in the T-cell receptor alpha locus from a clone of somatic cell hybrids carrying a t(14;14)(q11;q32) chromosomal translocation derived from an ataxia telangiectasia patient with T-cell chronic lymphocytic leukemia. The T-cell clone carrying the t(14;14) chromosomal translocation was known to be present for greater than 10 years before the onset of overt leukemia. One molecular rearrangement of the T-cell receptor alpha locus corresponded to a functional variable-joining region (V-J) joining, whereas the other derived from the breakpoint of the t(14;14)(q11;q32) translocation. Chromosomal in situ hybridization of the probe derived from the t(14;14) breakpoint localized the breakpoint region to 14q32.1, apparently the same region that is involved in another ataxia telangiectasia characteristic chromosome translocation, t(7;14)(q35;q32). The 14q32.1 breakpoint is at least 10,000 kilobase pairs (kbp) centromeric to the immunoglobulin heavy chain locus. Sequence analysis of the breakpoint indicates the involvement of a J alpha sequence during the translocation. Comigration of high-molecular weight DNA fragments involved with t(7;14) and t(14;14) translocations suggests the presence of a cluster of breakpoints in the 14q32.1 region, the site of a putative oncogene, TCL1.     

A gamma delta+ T-cell leukemia bearing a novel t(8;14)(q24;q11) translocation demonstrates spontaneous in vitro natural killer-like activity.

A highly malignant human T-cell leukemia was identified by cell surface analysis as a member of the T-cell receptor (TCR) gamma delta lineage. Cytogenetic and molecular analysis showed a novel t(8;14)(q24;q11) rearrangement involving the J delta 1 gene segment on chromosome 14 and the distal end of chromosome 8 near the c-myc proto-oncogene locus. The gamma delta TCR of the leukemia blasts was functionally intact and could be activated to generate intracellular calcium flux and to target Fc receptor-mediated redirected tumor cell lysis. In addition, non-major histocompatibility complex restricted lysis of a limited target cell panel was shown by fresh leukemic blasts and by the in vitro-maintained leukemia cells that was comparable to known T-cell lines with natural killer-like activity. These data suggest that the T-cell leukemia potentially had in vivo functional cytolytic activity. However, whether this activity did contribute to the patient's clinical condition could not be determined.     

Recent advances in clinical research on T-cell lymphoma

Immunophenotypic analysis on 34 cases of T-cell malignancies using monoclonal antibodies against T-cell receptors (TCR) revealed 25 cases of alpha beta-type and two of gamma delta-type. The two patients with gamma delta-type showed cutaneous involvement of tumor cells. Immunoblastic lymphadenopathy (IBL)-like T-cell lymphoma is divided into three histologic categories; inconspicuous type, patchy type and diffuse type. DNA hybridization analysis revealed that 11 of 16 cases showed clonal rearrangement of TCR beta-chain gene without rearrangement of immunoglobulin heavy chain gene, providing strong evidence for clonal proliferation of T-cells. Among 185 patients with adult T-cell leukemia (ATL), 18 cases (9.7%) were found not to be associated with human T-cell leukemia virus type I (HTLV-I). They consisted of 10 of acute type, five of chronic type, two of lymphoma type and one of smoldering type, indicating a diversity in clinical features. Two Japanese patients with ATL developed secondary monoclonal B-cell lymphomas of diffuse, large cell, non-Burkitt type. They were seropositive for HTLV-I but negative for human immunodeficiency virus (HIV). They also suffered from pulmonary tuberculosis, and one from adenovirus type 11-induced hemorrhagic cystitis, indicating an immunodeficient state. Epstein-Barr virus genome was found in lymphoma cells from one patient. It is suggested that opportunistic B-cell lymphomas may occur in the immunodeficient stage of ATL.     

T-cell receptor delta/alpha rearrangements in lymphoid neoplasms

Rearrangements within the T-cell receptor (TCR)delta/alpha locus were analyzed in a wide variety of lymphoid neoplasms by eight DNA probes specific for TCR J delta, J alpha and C alpha segments. In all 11 T- cell malignancies, rearrangement and/or deletion of TCR delta was detected irrespective of the stage of maturation of the tumor. The organization of TCR delta correlated with the phenotype of the tumor: In "prethymic" T-cell acute lymphocytic leukemia (ALL), TCR delta was the only TCR gene to be rearranged. More mature T cell malignancies expressing CD4 together with CD3 showed deletion of both alleles of TCR delta, suggestive of TCR V alpha-J alpha rearrangement. All 43 B-cell tumors expressing surface immunoglobulin (sIg), including two cases of adult B-cell ALL, had germline configuration of TCR delta/alpha. In contrast, all 17 B-cell precursor ALLs (null, common, and pre-B-cell ALLs) had rearrangement and/or deletion of TCR delta/alpha. A single case of "histiocytic" lymphoma also showed biallelic deletion of TCR delta. Oligoclonal rearrangements of Ig and TCR genes were observed in two cases of B-cell precursor ALL and in one case of T-cell lymphoblastic lymphoma. Patterns of such "aberrant" TCR rearrangement were similar to those observed in T-lineage malignancies. In particular, seven of eight cases of B-cell precursor ALL and the histiocytic lymphoma which demonstrated biallelic TCR delta deletion, (suggestive of a V alpha-J alpha rearrangement) had clonal TCR beta rearrangement. These data support the hypothesis that supposedly aberrant rearrangements of the TCR genes may follow the same developmental controls as found in T-cell differentiation, despite the lack of evidence for further commitment to the T-cell lineage. TCR delta rearrangement is a useful marker of clonality of immature T-cell tumors which may have only this gene rearranged but is not specific to the T-cell lineage.     

Cloning of the gene encoding the delta subunit of the human T-cell receptor reveals its physical organization within the alpha-subunit locus and its involvement in chromosome translocations in T-cell malignancy.

By taking advantage of "chromosomal walking" techniques, we have obtained clones that encompass the T-cell receptor (TCR) delta-chain gene. We analyzed clones spanning the entire J alpha region extending 115 kilobases 5' of the TCR alpha-chain constant region and have shown that the TCR delta-chain gene is located over 80 kilobases 5' of C alpha. TCR delta-chain gene is rearranged in the gamma/delta-expressing T-cell line Peer and is deleted in alpha/beta-expressing T-cell lines. Sequence analysis of portions of this genomic region demonstrates its identity with previously described cDNA clones corresponding to the C delta and J delta segments. Furthermore, we have analyzed a t(8;14)-(q24;q11) chromosome translocation from a T-cell leukemia and have shown that the J delta segment is rearranged in cells deriving from this tumor and probably directly involved in the translocation. Thus, the newly cloned TCR delta chain is implicated in the genesis of chromosome translocations in T-cell malignancies carrying cytogenetic abnormalities of band 14q11.     

A new case of acute lymphoblastic leukemia B-cell type with chromosomal rearrangements involving the T-cell receptor breakpoint at band 14q11.

A patient with B-cell acute lymphoblastic leukemia (ALL) and a translocation t(8;14) (q24;q11) is described. Translocation t(8;14)(q24;q32) is commonly associated with B-cell leukemia; nevertheless, translocations affecting chromosome 14 at band q11 are associated with T-cell malignancies, since the locus 14q11 contains genes that encode for the alpha and delta chains of the T-cell receptor (TCR). This finding points to the idea that the association between 14q11 rearrangements and T-cell neoplasia is less than complete.     

Defective synthesis or association of T-cell receptor chains underlies loss of surface T-cell receptor-CD3 expression in enteropathy-associated T-cell lymphoma

Enteropathy-associated T-cell lymphoma, an often fatal complication of celiac disease, can result from expansion of aberrant intraepithelial lymphocytes in refractory celiac disease type II (RCD II). Aberrant intraepithelial lymphocytes and lymphoma cells are intracellularly CD3epsilon(+) but lack expression of the T-cell receptor (TCR)-CD3 complex on the cell surface. It is unknown what causes the loss of TCR-CD3 expression. We report the isolation of a cell line from an RCD II patient with the characteristic phenotype of enteropathy-associated T-cell lymphoma. We demonstrate that in this cell line the TCR-alpha and -beta chains as well as the CD3gamma, CD3delta, CD3epsilon, and zeta-chains are present intracellularly and that assembly of the CD3gammaepsilon, CD3deltaepsilon, and zetazeta-dimers is normal. However, dimerization of the TCR chains and proper assembly of the TCR-CD3 complex are defective. On introduction of exogenous TCR-beta chains, but not of TCR-alpha chains, assembly and functional cell surface expression of the TCR-CD3 complex were restored. Defective synthesis of both TCR chains was found to underlie loss of TCR expression in similar cell lines isolated from 2 additional patients. (Pre)malignant transformation in RCD II thus correlates with defective synthesis or defective association of the TCR chains, resulting in loss of surface TCR-CD3 expression.