Chromosomes and causation of human cancer and leukemia. XLVIII. T-cell acute leukemia in ataxia telangiectasia

The natural history of ataxia-telangiectasia (A-T): A systematic review

BACKGROUND

Ataxia-telangiectasia is an autosomal recessive, multi-system, and life-shortening disease caused by mutations in the ataxia-telangiectasia mutated gene. Although widely reported, there are no studies that give a comprehensive picture of this intriguing condition.

OBJECTIVES

Understand the natural history of ataxia-telangiectasia (A-T), as reported in scientific literature.

SEARCH METHODS

107 search terms were identified and divided into 17 searches. Each search was performed in PubMed, Ovid SP (MEDLINE) 1946-present, OVID EMBASE 1980 -present, Web of Science core collection, Elsevier Scopus, and Cochrane Library.

SELECTION CRITERIA

All human studies that report any aspect of A-T.

DATA COLLECTION AND ANALYSIS

Search results were de-duplicated, data extracted (including author, publication year, country of origin, study design, population, participant characteristics, and clinical features). Quality of case-control and cohort studies was assessed by the Newcastle-Ottawa tool. Findings are reported descriptively and where possible data collated to report median (interquartile range, range) of outcomes of interest.

MAIN RESULTS

1314 cases reported 2134 presenting symptoms. The most common presenting symptom was abnormal gait (1160 cases; 188 studies) followed by recurrent infections in classical ataxia-telangiectasia and movement disorders in variant ataxia-telangiectasia. 687 cases reported 752 causes of death among which malignancy was the most frequently reported cause. Median (IQR, range) age of death (n = 294) was 14 years 0 months (10 years 0 months to 23 years 3 months, 1 year 3 months to 76 years 0 months).

CONCLUSIONS

This review demonstrates the multi-system involvement in A-T, confirms that neurological symptoms are the most frequent presenting features in classical A-T but variants have diverse manifestations. We found that most individuals with A-T have life limited to teenage or early adulthood. Predominance of case reports, and case series demonstrate the lack of robust evidence to determine the natural history of A-T. We recommend population-based studies to fill this evidence gap.

Abnormalities of chromosomes 8, 11, 14, and X in T-prolymphocytic leukemia studied by fluorescence in situ hybridization

Twenty-one patients with T-prolymphocytic leukemia (T-PLL) were studied by FISH to characterize abnormalities of chromosomes 8, 11, 14, and X. A higher percentage of abnormalities of these chromosomes was detected by FISH than by cytogenetics. Seventy-one percent had inv(14) (q11q32)/t(14;14)(q11;q32). Four patients had abnormalities involving Xq28 (MTCP-1 locus) resulting from t(X;14)(q28;q11) or t(X;7)(q28;q35). These abnormalities have also been described in persistent expanding pre-malignant T-cell clones in patients with ataxia telangiectasia (AT). We have previously reported that in T-PLL and AT developing T-cell leukemia, the above abnormalities occur with additional abnormalities, mainly trisomy for 8q resulting predominantly from an i(8)(q10) and an increased expression of MYC. In this series, 81% of cases had chromosome 8 abnormalities including i(8)(q10)[43%]/t(8;8)(p12;q11)[14%], + 8[14%], and 8p + [14%]. The use of probes for MYC (8q24) and chromosome 8 centromere on metaphase chromosomes revealed that cases with i(8)(q10) were dicentric and t(8;8) monocentric. These abnormalities are not only associated with increase in dosage of 8q and the MYC gene, but also involved 8p. 8p is known to have several suppressor genes associated with solid tumors. Our findings suggest that the possible loss of a tumor suppressor gene plus the increased dosage of the q arm and/or the high expression of TCL-1/MTCP-1, which results from inv(14)/t(14;14), allows the malignant phenotype to emerge.

Cytogenetic analysis in ataxia telangiectasia with malignant lymphoma

We present the results of cytogenetic analysis in a brother and sister with ataxia telangiectasia (AT), one of whom had malignant T-cell lymphoma. In both children, cytogenetic analysis of phytohemagglutinin (PHA)-stimulated lymphocytes showed chromosomal instability and inv(7) in 10% of the cells examined. The malignant lymphoma was analyzed cytogenetically on slides obtained from short-term culture of the lymph node cells; 64 cells were analyzed. A heterogeneous cell population was noted. Fourteen cells (21.9%) had a normal male karyotype; t(7;14)(p14;q12) and inv(7)(p14q35) were observed in 6.3% and 3.1% of metaphases. Owing to low frequency, these cells are probably a characteristic of the basic disease and have no features of malignant cells. Forty cells (62.5%) had a pseudodiploid karyotype 46,XY,dup(1)(p22p36),del(5)(q33),del(12)(p11), without cytogenetically evident aberrations of chromosomes 7 and 14. The results of these investigations suggest that the cells with rearrangements of chromosomes 1, 5, and 12 are malignant cells and did not originate by transformation of cells with inv(7) and t(7;14).

Genetic and cytogenetic changes in acute lymphoblastic leukemia

In recent years, a number of non-random chromosomal alterations have been identified in specific populations of acute lymphoblastic leukemic cells of either B-cell or T-cell lineage. The most frequently involved chromosomal sites are 1q, 4q, 6q, 7q, 8q, 9p, 9q, 10q, 11p, 12p, 14q, 19p and 22q. Genes located near frequent breakpoints include c-myc, c-abl and the genes for the T-cell alpha and beta receptors. In addition, approximately 20 other genes potentially involved in the leukemic process are located near less frequently encountered, but consistent, chromosomal breakpoints.

Ataxia telangiectasia and acinic cell carcinoma of the parotid gland

An increased incidence of malignancies occurs in ataxia telangiectasia. These are most frequently hematopoietic in children and epithelial in adults. Both cellular immunodeficiency and chromosome damage have been implicated in their etiology. There has been only one report of a salivary malignancy, a parotid mucoepidermoid carcinoma. We describe a second salivary malignancy, a metastasizing acinic cell carcinoma of the parotid gland, that developed in a 33-yr-old woman with ataxia telangiectasia. The marked chromosomal abnormalities that were present may have been involved in the pathogenesis of her tumor.

Cytogenetic studies in T-cell malignancies

Clonal chromosome abnormalities in ten cases of T-cell lymphoproliferative disorders are reported. In addition, an extensive review of the literature on T-cell lymphomas shows the chromosomal sites most frequently involved in structural rearrangements.

Distinct chromosome abnormalities in ataxia telangiectasia with chronic T-cell lymphocytic leukemia

We report chromosomal studies of a 27-year-old male patient with ataxia telangiectasia who developed a chronic T-cell lymphocytic leukemia. The leukemic cells grew spontaneously although a better yield of metaphases could be obtained after PHA stimulation. Chromosome analysis revealed a hypodiploid leukemic clone (44 chromosomes) and a single remaining normal metaphase. An isochromosome 8q was detected in a subclone at an early analysis, which was lost during clonal evolution. At the time of the last analysis, 6 months before the patient died, the diploid metaphases disappeared completely. The karyotype of the final chromosome study showed a monoclonal condition with the following abnormalities: 44,X,-Y,4q-,6p-,14q-,19p+,20q+,-20,22q-. Loss of the Y chromosome was limited to the leukemic cells. Comparing our data with the chromosome abnormalities reported in the literature, breakpoints at band 14q11-12 (location of the gene for the alpha chain of the T-cell receptor), loss of a normal chromosome #20, as well as structural abnormalities of the remaining chromosome 20p seem to be nonrandom in T-CLL arising in patients with ataxia telangiectasia. A Philadelphia-like marker that seems to be a peculiar feature of the case described here, however, resembles a small marker chromosome qualified as unidentifiable in a similar case of T-CLL reported in the literature.

Common mechanism of chromosome inversion in B- and T-cell tumors: relevance to lymphoid development

An inversion of chromosome 14 present in the tumor cells of a patient with childhood acute lymphoblastic leukemia of B-cell lineage was shown to be the result of a site-specific recombination event between an immunoglobulin heavy-chain variable gene and the joining segment of a T-cell receptor alpha chain. This rearrangement resulted in the formation of a hybrid gene, part immunoglobulin and part T-cell receptor. Furthermore, this hybrid gene was transcribed into messenger RNA with a completely open reading frame. Thus, two loci felt to be normally activated at distinct and disparate points in lymphocyte development were unified and expressed in this tumor.

Cis-trans position effect in cancer translocations

Translocations of chromosomes occurring in human cancer cells appear specific to the type of cell from which the cancer arises. To explain the action of these translocations, we propose dual position effect: Position effect of the cis type transforms the cell to malignancy, while position effect of the trans type permits the normal homologous chromosome to express a normal gene product. Thus, the translocation itself has to do with malignant transformation, while the normal homologous chromosome performs its normal function. This dual concept is illustrated by t(8;14) in Burkitt's lymphoma. The concept can be tested with t(2;18) and t(8;22) in lymphoid malignancies and with other translocations and chromosome rearrangements marking human cancer cells.

Non-random in vitro 7;14 translocations detected in a routine cytogenetic series. 12 examples and their possible significance

This study describes 12 examples of translocations between chromosomes 7 and 14 in short-term peripheral blood lymphocyte cultures from 10 patients investigated in a routine cytogenetic series. Only one constant breakpoint was found on 14q, and chromosome 7 had two constant breakpoints, one on 7p and the other on 7q. The cause and true significance of such nonrandom in vitro chromosome translocations is not known at present, but one may speculate as to their possible indication of heterozygosity for a chromosome instability syndrome and thus a predilection for the development of lymphoid or other malignancy.