Cytogenetic findings in secondary acute nonlymphocytic leukemia

Karyotype abnormalities in a variant Chinese hamster cell line resistant to methyl methanesulphonate

A variant cell population, isolated from V79-C13 Chinese hamster cells after two consecutive treatments with methyl methanesulphonate (MMS), was found to be highly resistant to killing by this alkylating agent. The resistant cell line was cytogenetically characterized both by the presence of a stable translocation involving metacentric chromosome 2 and acrocentric chromosome 6 and by a supernumerary chromosome originated by the duplication of a small telocentric chromosome. This cell population also showed a transient transformed phenotype, seen as formation of transformed foci containing cells with high chromosomes counts and multiple chromosomal aberrations. As MMS-resistance and karyotype changes are permanent and heritable traits, we suppose that they are related events.

Acute myeloid leukemia with t(5;18)(q35;q21)

A case of acute myelocytic leukemia with a translocation (5;18)(q35;q21) is reported. Cytogenetic abnormalities of the long arm of chromosome 5 have long been known to affect hematopoiesis. Although translocations between 5q and other chromosomes have been associated with malignancy, this is the first reported case of a t(5;18) resulting in acute myeloid leukemia. Possible molecular mechanisms underlying the pathogenesis of the disease are discussed.

Progressive Telomere Shortening in Aplastic Anemia

Improved survival in aplastic anemia (AA) has shown a high incidence of late clonal marrow disorders. To investigate whether accelerated senescence of hematopoietic stem cells might underlie the pathophysiology of myelodysplasia (MDS) or paroxysmal nocturnal hemoglobinuria (PNH) occurring as a late complication of AA, we studied mean telomere length (TRF) in peripheral blood leukocytes from 79 patients with AA, Fanconi anemia, or PNH in comparison with normal controls. TRF lengths in the patient group were significantly shorter for age than normals (P < .0001). Telomere shortening was apparent in both granulocyte and mononuclear cell fractions, suggesting loss at the level of the hematopoietic stem cell. In patients with acquired AA with persistent cytopenias (n = 40), there was significant correlation between telomere loss and disease duration (r = −.685; P < .0001), equivalent to progressive telomere erosion at 216 bp/yr, in addition to the normal age-related loss. In patients who had achieved normal full blood counts (n = 20), the rate of telomere loss had apparently stabilised. There was no apparent association between telomere loss and secondary PNH (n = 13). However, of the 5 patients in the study with TRF less than 5.0 kb, 3 had acquired cytogenetic abnormalities, suggesting that telomere erosion may be relevant to the pathogenesis of MDS in aplastic anemia.

Progressive Telomere Shortening in Aplastic Anemia

Improved survival in aplastic anemia (AA) has shown a high incidence of late clonal marrow disorders. To investigate whether accelerated senescence of hematopoietic stem cells might underlie the pathophysiology of myelodysplasia (MDS) or paroxysmal nocturnal hemoglobinuria (PNH) occurring as a late complication of AA, we studied mean telomere length (TRF) in peripheral blood leukocytes from 79 patients with AA, Fanconi anemia, or PNH in comparison with normal controls. TRF lengths in the patient group were significantly shorter for age than normals (P < .0001). Telomere shortening was apparent in both granulocyte and mononuclear cell fractions, suggesting loss at the level of the hematopoietic stem cell. In patients with acquired AA with persistent cytopenias (n = 40), there was significant correlation between telomere loss and disease duration (r = −.685; P < .0001), equivalent to progressive telomere erosion at 216 bp/yr, in addition to the normal age-related loss. In patients who had achieved normal full blood counts (n = 20), the rate of telomere loss had apparently stabilised. There was no apparent association between telomere loss and secondary PNH (n = 13). However, of the 5 patients in the study with TRF less than 5.0 kb, 3 had acquired cytogenetic abnormalities, suggesting that telomere erosion may be relevant to the pathogenesis of MDS in aplastic anemia.

Karyotypic and clinical progression of ANLL in a patient with constitutional der(15;21)(q10;q10)

A patient with a constitutional chromosomal abnormality who developed acute nonlymphocytic leukemia (ANLL-M4) at the age of 31 is presented. At the time of diagnosis the only acquired chromosomal change was the presence of a small marker chromosome. The patient was studied periodically for 11 years during his illness with no evidence of karyotypic progression, until the last study, when a deletion of the long arm of chromosome 7 was detected.

Treatment of children with epipodophyllotoxin-induced secondary acute myeloid leukemia

BACKGROUND

Secondary acute myeloid leukemia (AML) after treatment with epipodophyllotoxins is being observed with increased frequency. Therapeutic options are limited for patients with secondary AML and the role of bone marrow transplantation is unclear.

METHODS

The authors report the treatment outcome of a cohort of 17 children who developed epipodophyllotoxin-induced secondary AML after therapy for childhood acute lymphoblastic leukemia (ALL) that included etoposide but no irradiation or alkylating agents. Thirteen patients (76%) had 11q23 chromosomal abnormalities that were not present at the initial diagnosis of ALL.

RESULTS

Remission induction was attempted in 16 children, with 13 (81%) achieving a complete remission. After consolidation, 9 of these 13 patients received a bone marrow transplant (BMT): 2 with 4-hydroperoxycyclophosphamide-purged autologous marrow, 4 from a human leukocyte antigen (HLA)-identical sibling, 1 from a mismatched parental donor, and 2 from a matched unrelated donor. One additional child underwent allogeneic BMT without an attempt at reinduction. Of the 10 patients who received transplants, 2 were alive and well 27+ and 36+ months, respectively, after BMT. Of the 7 patients who did not receive a transplant, at last follow-up 1 had survived off therapy for 8 months for recurrent ALL whereas 6 died of AML.

CONCLUSIONS

These data confirm the poor prognosis of secondary AML after epipodophyllotoxin treatment for childhood ALL. Although patients with secondary AML can achieve a remission, it is usually of brief duration. Allogeneic BMT may offer the possibility of long term remission in some of these patients. More information is needed to better define the risks and benefits of epipodophyllotoxin therapy for childhood ALL.

Translocation (12;15)(p13;q13) in a patient with relapsed acute myeloid leukemia

We report a patient with a history of leukopenia who developed acute myeloid leukemia (AML) FAB M2 and was successfully treated with induction and consolidation chemotherapy. She relapsed 7 months after initial diagnosis. Peripheral blood cells at relapse showed a t(12;15)(p13;q13), which has not been previously described in de novo or relapsed AML.

A new pericentric inv(8) in acute nonlymphocytic leukemia

Chromosome studies were carried out on unstimulated bone marrow cells from a patient with a diagnosis of acute nonlymphocytic leukemia (FAB M6 ANLL). Cytogenetic analysis revealed a mosaic chromosome pattern 46,XX/46,XX,inv(8)(p21q24). This pericentric inversion has not been previously described in ANLL. Because, fragile sites, zinc finger gene loci, and the MYC protooncogene have been localized to band 8q24, a putative role for these sites and genes could be considered.

Specific chromosomal translocations and therapy-related leukemia induced by bimolane therapy for psoriasis

This paper reports for the first time results of cytogenetic studies on 14 consecutive secondary acute non-lymphocytic leukemia (S-ANLL) induced by bimolane therapy. They included 10 males and 4 females with ages ranging from 17 to 54 years. They had all suffered from psoriasis and received bimolane treatment before the occurrence of their leukemia. The total dose of bimolane ranged from 40 to 400 g (mean dose 194 g). The interval between the initiation of bimolane therapy and the diagnosis of leukemia was 12-96 months (median 30 months). A preleukemic phase was only found in one case. No dysplastic features in the hemopoietic series were seen in any patient. Chromosome analysis of bone marrow cells using banding techniques revealed clonal karyotypic abnormalities in all cases: t(15;17) in 8 cases of M3, of which 75% had extra abnormalities, t(8;21) in 4 cases of M2, del(7q) only in one case of M4 and one case of M5. After antileukemic therapy, complete remission was obtained in 10 out of 12 cases with specific translocations and one out of 2 cases with 7q-anomaly, respectively. The former survived 4-58 months (median 12 months), while the latter 1 and 9 months, respectively. This study indicates that: (1) bimolane is a causative factor of leukemia in this series; (2) the leukemia in our series is therapy-related leukemia (TRL) rather than de novo ANLL; (3) there exists, in fact, a new subgroup of TRL characterized by specific rearrangements, whose clinical, hematological and prognostic features and pathogenetic mechanism may be different from classical TRL characterized by chromosome abnormalities involving absence or deletion of parts of chromosome 5 and/or 7.