Acute lymphocytic leukemia (ALL) with near-haploidy—A unique subgroup of ALL?

Near-haploid and low-hypodiploid acute lymphoblastic leukemia: two distinct subtypes with consistently poor prognosis

Hypodiploidy <40 chromosomes is an uncommon genetic feature of acute lymphoblastic leukemia (ALL) in both children and adults. It has long been clear by cytogenetic analyses, and recently confirmed by mutational profiling, that these cases may be further subdivided into 2 subtypes: near-haploid ALL with 24 to 30 chromosomes and low-hypodiploid ALL with 31 to 39 chromosomes. Both groups are associated with a very poor prognosis, and these patients are among those who could benefit most from novel treatments.

Reassessment of the prognostic significance of hypodiploidy in pediatric patients with acute lymphoblastic leukemia

BACKGROUND

The purpose of the current study was to evaluate the cytogenetic features of the hypodiploid leukemic cells of pediatric patients with this rare subgroup of acute lymphoblastic leukemia (ALL). In addition, the authors determined whether subdivision of the hypodiploid category served a prognostic purpose for these patients.

METHODS

The authors evaluated the cytogenetic records of 979 patients with ALL admitted to St. Jude Children's Research Hospital (Memphis, TN) between 1984 and 1999.

RESULTS

Of 67 patients (6.8%) whose leukemic cells contained a modal number (MN) of chromosomes less than or equal to 45 (i.e., hypodiploid leukemic cells), 57 had an MN of 45 and 10 had an MN of less than 45. In 19 patients, cells with an MN of 45 had a whole chromosome missing (42%), which was a sex chromosome in 12 patients (63%). Leukemic cells with an MN of 45 contained dicentric chromosomes (n = 33) formed from chromosome 9p (55%), 12p (18%), or both (21%). The ETV6-CBFA2 fusion was present in 39% of 28 evaluable B-lineage cases with an MN of 45. The event-free survival rate (EFS) for patients with hypodiploid leukemic cells of MN less than 45 (5-year EFS = 20.0% +/- 10.3%) was significantly (P < 0.001) lower than that for patients with leukemic cells of MN greater than or equal to 45 (5-year EFS = 74.9% +/- 1.6%).

CONCLUSIONS

Low hypodiploidy (MN < 45) should be recognized as a high-risk feature in pediatric ALL. Only two hypodiploid groups (MN < 45 and MN = 45) may be necessary in prognostic assessments.

Near haploid childhood acute lymphoblastic leukemia masked by hyperdiploid line: detection by fluorescence in situ hybridization

Near-haploid (<30 chromosomes) acute lymphoblastic leukemia (ALL) is a rare and unique subgroup of childhood common ALL associated with a very poor outcome. It may be underdiagnosed when masked by a co-existing hyperdiploid line, which has to be distinguished from the common good-prognostic hyperdiploid (>50 chromosomes) ALL. We present three children in whom, by conventional cytogenetics, near-haploid ALL was detected on relapse. Using interphase FISH probes of chromosomes X, Y, 4, 12, and 21, we were able, in two cases, to trace the hidden near-haploid lines of approximately 5% and 20% of the cells, masked by hyperdiploid cells of approximately 80% and 70%, respectively; at relapse, the proportion was reversed, with predominant near-haploid lines of over 80% and residual hyperdiploidy of less than 10%. The near-haploid lines consisted of 24 and 27 chromosomes, and always retained the second copy of chromosome 21 or its derivative, as detected in one of our patients by SKY. The hyperdiploid clones were the exact duplicates of the near-haploid ones and contained four and two copies of the chromosomes represented in two and one copies in the near-haploid stem line, respectively. Unlike the common hyperdiploid ALL, no trisomies were observed. The patients were all aged >10 years, with WBC 0.7-30 x 10(9)/L, and a common ALL phenotype. They were treated with the ALL-BFM-95 protocol, medium risk group, and responded well to 8 days of steroid therapy, but relapsed early, within 11 months, and died a few months later. Interphase FISH technique is recommended for the detection of cryptic near-haploid clones in the diagnostic survey of ALL. To assess the prognostic value of near-haploidy in the context of the ALL-BFM protocols, a larger cohort of patients is required.

Near-haploid common acute lymphoblastic leukaemia of childhood with a second hyperdiploid line: a DNA ploidy and fluorescence in-situ hybridization study

Near-haploidy is a rare cytogenetic finding in childhood acute lymphoblastic leukaemia (ALL) and is associated with a poor prognosis. A second hyperdiploid line, occurring presumably by endoreduplication of the near-haploid stemline, is often observed. We present a case of common ALL in relapse characterized morphologically by a dual population of small and large lymphoblasts. Cytogenetic analysis supplemented with fluorescence in-situ hybridization (FISH) studies localized near-haploidy and hyperdiploidy to the small and large blast population respectively. DNA ploidy determination confirmed two abnormal clones with near-haploidy as the predominant one. A novel t(9;12)(q11;q13) was present in the near-haploid clone and was duplicated in the hyperdiploid clone. This finding identified cells bearing near-haploidy to be the clonogenic population following malignant transformation and confirmed endoreduplication as the mechanism for the presence of associated hyperdiploidy.

A near-haploid bone marrow karyotype in systemic mast cell disease: is it characteristic of the disease or an incidental finding?

We present the case of a 40-year-old man with aggressive systemic mast cell disease. The patient had a predominant near-haploid clone in his bone marrow cells, detected by cytogenetic analysis performed at the time of diagnosis. The similarities between this case and a previously published case of near-haploidy in a patient with malignant mastocytosis suggest that near-haploidy may be a characteristic of aggressive systemic mast cell disease rather than an incidental finding.

Hyperdiploidy arising from near-haploidy in childhood acute lymphoblastic leukemia

Acute lymphoblastic leukemia (ALL) of childhood is frequently characterized by a hyperdiploid karyotype. Typically, most of the affected chromosomes in the abnormal clone are present in three copies. We have studied two patients with hyperdiploid ALL whose leukemic cells were atypical in that all or most of the chromosomes were present in either two or four copies, raising a suspicion that the observed karyotype arose through duplication of chromosomes in a precursor cell with a near-haploid chromosome number. Analysis of restriction fragment length polymorphisms confirmed that both cases arose from a near-haploid cell; all informative disomic chromosomes tested had loss of heterozygosity. Furthermore, the hyperdiploid karyotypes did not arise via a perfect haploid cell with exactly 23 chromosomes, because tetrasomic chromosomes remained heterozygous. These two patients probably are classified best as near-haploid cases, which often are observed to have a co-existing hyperdiploid clone with a duplicated chromosome set. The distinction between typical hyperdiploidy and hyperdiploidy arising via a near-haploid cell may be clinically important, because the prognosis for patients with a hyperdiploid karyotype is favorable in comparison to that of patients with a near-haploid karyotype.

Cytogenetic and flow cytometric analysis of a clear cell chondrosarcoma

Cytogenetic analysis of a rare tumor, a clear cell chondrosarcoma of the spine, showed unusual karyotypic findings. The tumor had a predominant clone with a near-haploid chromosome complement of 30 chromosomes with loss of one homologue of each chromosome pair except chromosomes 5, 7, 12, and 19-22. A second clone with 58-60 chromosomes appeared to have originated by a doubling of the near-haploid clone. No structural changes were present. Comparison with other solid tumors and leukemias with near-haploid chromosome complements showed an interesting difference in the chromosomes which were preferentially disomic or monosomic in the two groups. Quantitative DNA analysis also showed aneuploid clones of cells corresponding to the near-haploid and hyperdiploid chromosome counts obtained cytogenetically.

Flow cytometric evidence for minimal residual disease and cytological heterogeneities in acute lymphoblastic leukemia with severe hypodiploidy

Two subpopulations of small and large leukemia cells and binucleated cells were present in the bone marrow of a 10-year-old girl with acute lymphoblastic leukemia (ALL). Cytogenetic studies showed some cells with a karyotype of 34,X,-X,-2,-3,-4,-5,-7,-9,-13,-15,-16,-17,-20, and others with a karyotype that was exactly double the chromosome set in the cells with 34 chromosomes. Flow cytometric (FCM) examination of surface common ALL antigen (CALLA) and DNA content of the lymphoblasts led to the identification of the primary hypodiploid DNA stemline (DI = 0.72), which corresponds to the small-sized blasts, and the secondary hyperdiploid DNA stemline (DI = 1.44), which corresponds to the large-sized blasts. Sequential bone marrow examinations with FCM and cytogenetics revealed the persistence of the primary hypodiploid clone during remission and their proliferation with chromosomal evolution at full relapse. These results suggest that more rational inductive therapy should be designed to achieve the favorable outcome of ALL with severe hypodiploidy and that FCM is a useful tool to monitor the minimal residual disease of this subgroup in ALL.

Origin of near-haploidy in malignant hematopoietic cells

Hyperdiploidy is common in neoplastic diseases but severe hypodiploidy or near-haploidy is extremely rare. Acute lymphocytic leukemia (ALL) and blast phase of chronic myelocytic leukemia (BC/CML) are the two most common leukemias where metaphases with as low as 23 chromosomes have been reported. Recent studies have indicated that during the course of malignant development, cells undergo numerous changes, however, it is still not known whether malignant transformation proceeds or results from the near-haploid state. Retrospectively, we have examined 100 metaphases with chromosome counts of 23 to 35 in patients with CML who have not yet progressed to the blastic phase, to see whether such metaphases share any common characteristics with published cases. The unusual behavior of chromosomes 8, 17 and the presence of Ph-chromosomes in 85% of the cells are highly unique features in our study. These observations are compatible with those found in BC/CML patients reported earlier. Therefore, it is hypothesized that selective chromosome loss is a gradual phenomenon and one of these near-haploid clones may replace a diploid clone as the dominant component of the population during blast transformation. Several hypotheses are proposed as to the origin of such clones in malignant hematopoietic stem cells.

Prospective study of childhood acute lymphocytic leukemia: hematologic, immunologic, and cytogenetic correlations

We studied the karyotype in 81 consecutively diagnosed children with acute lymphocytic leukemia (ALL) treated at one institution on a randomized treatment protocol. In 75 patients (93%), a morphological cytogenetic result was obtained, and 57 (65%) were successfully G-banded. Of the 75 patients, 46 (61%) showed abnormal chromosomes, mainly hyperdiploidy and pseudodiploidy, and 29 had no detectable abnormality. Our findings confirmed that the karyotype has prognostic significance. Duration of complete remission was 93% at 42 months for patients with high hyperdiploidy (greater than 50). For patients with an apparently normal karyotype, it was 58%; and for patients with structural abnormalities it was 15%. The significance of these findings was confirmed by multivariate analysis, which showed age and karyotype to be the most important determinants of duration of remission.

Near-haploidy in childhood leukemia: a high-risk component

We present a 4-year-old girl with acute lymphocytic leukemia (ALL) and only 25 chromosomes at cytogenetic examination of her bone marrow. Severe hypodiploidy is extremely rare in childhood leukemia and is almost exclusively associated with ALL. To our knowledge only six cases with banded metaphases have been published. The chromosome number in the present case is the lowest ever reported. Our patient as well as other reported cases have disomy for chromosome 21. The prognosis for ALL with hypodiploidy is poor with a reported mean survival of 9 months. All published patients are females.

Hybrid biphenotypic acute leukemia with extreme hypodiploidy

A patient diagnosed as having acute lymphoblastic leukemia (L2) relapsed 4 months later and was found to have morphologic and immunologic evidence of a biphenotypic hybrid acute leukemia. Chromosome analysis at relapse showed two abnormal clones, one with marked hypodiploidy and the other with exactly double the hypodiploid clone. It is considered that this is an example of a hybrid lymphoblastic/nonlymphoblastic leukemia with unique karyotype.

Ph-positive chronic myeloid leukemia with near-haploid conversion in vivo and establishment of a continuously growing cell line with similar cytogenetic pattern

Blast cells from a 39-year-old man in the blastic phase of chronic myeloid leukemia, with a benign phase of 15 years duration, as well as a cell line arising from this cell population, were studied. Cellular morphology, cytochemical staining pattern, and absence of terminal deoxynucleotidyl transferase showed the blast cells to be of myeloid character. Cytogenetic studies revealed the presence of two near-haploid cell populations with +8 and +8, +15, respectively, both of them containing the translocation t(9;22) in the original tumor cell sample. The cell line derived from this patient's leukemic cell sample contained both near-haploid and hyperdiploid clones, the hyperdiploid clones being multiples of the near-haploid clone(s). All of the clones carried the t(9;22) in the form of a Philadelphia chromosome.

Near-haploidy in a case of plasmocytoma

Chromosome studies of a solitary plasmocytoma in the femoral bone revealed a near-haploid chromosome number of 31-32 with a loss of one homolog of each chromosome pair except #1, #7, #9, #15, #19-21, and the sex chromosomes (XY). The cytogenetic findings have been compared with 16 cases of near-haploid neoplasms from the literature studied using banding techniques. A common feature present in 13 of the 16 cases reported was found to be disomy 21; the only chromosomes consistently present in one copy in all neoplasms were #2, #3, #4, and #5.

Near-triploid Ph-positive leukemia

Tetraploid populations have been observed in various types of leukemia, but relatively few reports exist of triploid cell populations in acute or chronic leukemia. We report two cases of Ph-positive leukemia with a modal triploid cell population. Examination of peripheral blood from a 3-year-old boy with Ph-positive acute lymphoblastic leukemia (ALL) and a 68-year-old male with Ph-positive chronic myelocytic leukemia (CML) in blastic crisis revealed modal populations of 72 and 63 chromosomes, respectively. G-banding analysis of both cases revealed the following: karyotypic instability (no clonality), dominant trisomy, and the random association of the Ph chromosome with gains and losses of chromosomes involved in this translocation. The cytogenetic evidence obtained suggests that the triploid cell populations were not derived from a duplication of a hypodiploid cell population, but resulted from random loss of chromosomes from tetraploid cell populations derived from duplication of pseudodiploid cells.

A case of acute lymphoblastic leukemia with severe hypodiploidy

A case of acute lymphoblastic leukemia with a severe hypodiploid chromosome constitution is reported. The modal chromosome number was 36, and the karyotype of these cells was 36,X, -X, -2, -3, -5, -7, -9, -12, -13, -15, -16, -17, -20, +21, +mar,del(1) (p13.1p22.3),inv(3)(q13.3q29). In addition to a haploid set, extra copies of chromosomes #6, #10, #14, #18, and #21 were found, as in most cases with severe hypodiploid karyotypes. A second, near-triploid cell line was also observed. An examination of chromosomal heteromorphisms suggested that the severe hypodiploid clone originated either from a near-triploid cell or from a common precursor cell.

24-36-Chromosome clones in human malignancies. Cytogenetic interrelationships, clinical significance and patient age

The literature has been reviewed for cases of malignant disease showing cellular clones with 24-36 chromosomes. Such cases are characterized by aggressive disease. Together the clones with 24-36 chromosomes compose a remarkably consistent non-random cytogenetic pattern, which demonstrates that different chromosomes are of different value for cellular survival and clonal propagation. Considering that the tissues of origin are very different (various solid tumours and different leukaemias), the close mutual cytogenetic relationship between the clones indicates that the cytogenetic pattern is tissue non-specific. Karyotypic non-specificity of cells with very different phenotypes is an apparent contradiction, which raises important questions concerning the relation between karyotype and phenotype.

Near-haploid cell line in the blastic crisis of chronic myelogenous leukemia: a possible marker for lymphoid malignancy

The blast cells of a 14-year-old patient in the blastic phase of chronic myelogenous leukemia (CML) were studied. Cellular morphology, presence of the enzyme terminal deoxynucleotidyl transferase (TdT), and reactivity to the common acute lymphoblastic leukemia antiserum (CALLA) substantiated a lymphoid blast cell line. Immunologic surface markers were nonreactive for E-rosette (T) cells and immunoglobulin-bearing (B) cells. Cytogenetic, studies revealed persistance of the Philadelphia chromosome and a near-haploid cell line, i.e., 28,XY,t(9;22), +14, +15, +21, +22(GTG). The patient responded to chemotherapy with vincristine, prednisone, and L-asparaginase, first line drugs used for remission-induction of acute lymphoblastic leukemia in childhood. We suggest that severe hypodiploidy or near-haploidy, along with TdT and CALLA, may provide more accurate prognostic information in patients with CML and the lymphoid blastic crisis.

Extreme hypodiploidy in a case of myelomonocytic crisis of chronic myelogenous leukemia

Two cytogenetically distinct populations of marrow cells were observed in a 28-year-old woman who developed a fulminant blastic crisis (BC) of chronic myelogenous leukemia (CML) after only 1 year in the chronic phase: one population with 35-36 chromosomes, the other showing 66-72 chromosomes. Cytochemical investigation demonstrated a myelomonocytic type of BC. Chromosome banding and correlation analysis of the mean karyotypes of the two populations showed that a close relationship existed between them, indicating that one population had developed from the other. The cytogenetic evidence suggests but does not prove that the cells with triploid chromosome numbers developed from the extremely hypodiploid population by duplication of the chromosome complement. The extreme cytogenetic diversity of both populations indicates that each was undergoing further cytogenetic evolution.

Chromosomes and causation of human cancer and leukemia. XLVII. severe hypodiploidy and chromosome conglomerations in ALL

A case of acute lymphoblastic leukemia (ALL) of the L1 type with severe hypodiploidy in the marrow cells (modal chromosome number, 36) is described. In addition, most of the metaphases contained chromosome conglomerations which consisted of varying numbers of chromosomes and appeared similar to conglomerations previously observed by us in a case of chronic myelocytic leukemia (CML) in the blastic phase (BP), where some cells contained less than 20 chromosomes. The karyotype of the ALL cells of our case was similar to those of published near-haploid ALL cases, possibly indicative of a common pathway of cytogenetic evolution.

Acute lymphocytic leukemia with microblastosis and near haploidy (26 chromosomes): a case report

A three-year-old acute lymphocytic leukemia (ALL) patient had a modal chromosome count of 26 in her bone marrow metaphases. The leukemia was "common" ALL by cytochemical and immunologic studies. Five other cases had been reported previously, and all have had a near haploidy varying from 26 to 32 chromosomes. Disomy of chromosomes 18 and 21 is a consistent feature of this disease. Severe hypodiploidy correlates with microblastosis requiring morphologic separation from non-neoplastic small lymphocytes.

Chromosomal findings and their correlation to prognosis in acute lymphocytic leukemia

Sixteen of the 17 patients with acute lymphocytic leukemia (ALL) were revealed to have chromosome abnormalities in their leukemic cells. Of nine children, six had modal chromosome numbers between 50 and 59; these patients and one additional patient with a pseudodiploid karyotype have achieved and retained a complete remission. The only patient without chromosome abnormalities achieved a remission, but had a relapse and died. The only child who expired without achieving a remission had 47 chromosomes in his leukemic cells. Of eight adults, none had the hyperdiploidy seen in the children. The four with hypo-or pseudodiploidy failed to achieve a complete remission. One patient had 47 chromosomes in his leukemic cells, and this patient and the remaining three, all with ploidy abnormalities, achieved a complete remission, but a relapse occurred and they died. The chromosomal abnormalities were very extensive in most cases, many patients having marker chromosomes of an unknown origin. Four patients clearly exhibited karyotypic evolution when they relapsed. The patients with hyperdiploidy had a better prognosis, and those with pseudodiploidy had a poorer prognosis. The role of individual chromosome aberrations, however, remains to be elucidated.

Cytogenetic analysis and flow cytometric DNA measurement of a human tumor with pronounced hypodiploidy

A case of malignant choroid plexus papilloma of the brain with severe hypodiploidy is presented. The hypodiploidy was estimated by means of flow cytometric measurements of the nuclear DNA content in two investigations with an interval of 21 months. The latter investigation was supplemented with chromosome analyses including quinacrine bonding. A modal chromosome number of 34 to 35 was found with a consistent loss of one chromosome Nos. 2, 3, 4, 5, 10, 13, 14, 15, 17, and 18, and no major structural changes. The corresponding calculated DNA content per nucleus correlated very well with the measured content, which was found to be 75% of the male diploid amount. The paper briefly discusses cell survival in extreme hypodiploidy and provides a comparison with cases from the literature in which banding analysis gives comparable information.

Chromosomes and causation of human cancer and leukemia: XXXIX. Usual and unusual findings in Ph1-positive CML

The chromosomal changes in the leukemic cells of 48 patients with Ph1-positive CML are reported. The karyotypic findings in the chronic phase (CP) and blastic phase (BP) were similar to those reported in the past, with +8, and extra Ph1, and an iso (17q) being the most common anomalies observed in BP. Unusual cytogenetic findings were observed in one patient whose cells (from lymph nodes, bone marrow, and blood) were characterized by very marked hypodiploidy and hypo-haploidy, with some of the cells having less than 20 chromosomes. In each of these very hypodiploid metaphases, conglomerations of darkly stained and condensed chromosomes were seen. These conglomerations consisted of a few to eight chromosomes. The role played by these chromosomes in the genesis of severe hypodiploidy is uncertain. The patient was thought to have "lymphoid" types of leukemic cells in BP, with an extramedullary origin of such cells, particularly in lymph nodes, playing a major role in the genesis of BP. The reported cases of near-haploidy with Ph1-positive CML and those with constitutional translocations with CML have been tabulated and the possible significance of the cytogenetic abnormalities discussed.