Cytogenetic evidence for involvement of erythroid progenitors in a child with therapy linked myelodysplasia

Progression of myelodysplasia to acute lymphoblastic leukaemia: implications for disease biology

Myelodysplastic syndrome (MDS) comprises a group of clonal haematopoietic disorders characterized by peripheral blood cytopenias, bone marrow hypercellularity, and abnormal blood cell differentiation. Approximately 30% of cases of MDS eventually progress to acute myelogenous leukemia (AML), while progression of MDS into acute lymphoblastic leukemia (ALL) is rare. In this report, we describe a case of MDS that progressed to ALL, and review the 21 previously reported cases of MDS to ALL transformation. We review the cancer stem cell model and its application to these disorders, and discuss the implications of the rarity of transformation of MDS to ALL for the biology of MDS and the pathogenesis of ALL.

Cytogenetic findings in 179 patients with myelodysplastic syndromes

Cytogenetic analyses were performed on 266 bone marrow and peripheral blood samples from 179 patients with myelodysplastic syndromes (MDS). According to the FAB classification, 42 patients presented with RA, 18 with RARS, 37 with RAEB, 22 with CMML, and 29 with RAEB-T. Nine patients showed a secondary MDS (S MDS). FAB classification was not available for 22 patients. Clonal karyotype anomalies were found in 92 patients (51.4%). Complex chromosome abnormalities occurred in 17 (18.5%) of them. An evolution of the karyotype was detected in 16 cases (17.4%). Cytogenetically independent cells or cell clones were found in eight patients. Nonclonal chromosome abnormalities were uncovered in 29 (16.2%) of the 179 MDS patients. Consecutive studies were performed in 48 patients and revealed a good correlation of initial karyotype and clinical course. The most frequent single anomalies were 5q- in 29 (31.5%), -7 in 22 (23.9%), trisomy 1q in 14 (15.2%), and +8 in 13 (14.1%) of 92 patients respectively. Our cytogenetic findings are presented in detail and discussed in relation to patients' age, morphological classification, clinical course, and prognostic impact. The contribution of cytogenetic findings to the delineation of multistep pathogenesis of MDS with special emphasis to karyotype instability is demonstrated.

Involvement of 11p15 and 3q21q26 in therapy-related myeloid leukemia (t-ML) in children. Case reports and review of the literature

The cytogenetic findings of therapy-related myeloid leukemia (t-ML) in three children are presented. These included one male patient with acute lymphoblastic leukemia (ALL) who underwent bone marrow transplantation and developed therapy-related myeloproliferative disease (t-MPD) in the female-donor hematopoietic cells 2.5 years after receiving radiation and epipodophyllotoxin therapy for ALL testicular relapse. Bone marrow leukemic cell karyotype revealed 46,XX,add (11)(p15) and a normal female karyotype in the peripheral blood lymphocytes. The other two children, one with ALL and one with ganglioneuroblastoma, developed fatal t-MPD and therapy-related acute myeloblastic leukemia (t-AML) preceded by myelodysplastic syndrome (t-MDS), respectively, 5 years after diagnosis, following administration of alkylating agents and irradiation. Monosomy 7 was present in both, and was combined with inv(3)(q21q26) in the second patient. Our review of the cytogenetic findings in 91 previously reported pediatric patients with t-ML suggested that the involvement of 11p15 and 3q21-->23, 3q24-q26 with or without a combination of translocation 11q23 and -7/7q-, respectively, are nonrandom aberrations of t-ML in children. Comparison of the chromosomal changes in t-ML between the pediatric and an adult series revealed some differences which may result from differences in treatment modalities and which, in addition, may indicate a possible role of genetic and/or age-dependent factors in the pathogenesis of therapy-related leukemogenesis in children.

Metastatic retinoblastoma successfully treated with immunomagnetic purged autologous bone marrow transplantation

There are no documented cases of long-term, disease-free survival in retinoblastoma (RB) metastatic to the bone marrow. The following study details successful outcome in a 3-year-old child with extensive marrow replacement 7 months postenucleation in an otherwise untreated group V RB. Therapy consisted of combinations of vincristine, doxorubicin, and cyclophosphamide for 3 months. After demonstrating cross-reactivity by a panel of six monoclonal neuroblastoma (NB) antibodies with the patient's RB cells, her marrow was purged by using microsphere-linked monoclonal antibodies, and then reinfused as rescue therapy after ablative doses of etoposide and cyclophosphamide. The authors conclude that short-term induction therapy followed by marrow ablative combination chemotherapy and immunomagnetically purged autologous marrow rescue can (1) effect successful outcome in widely metastatic RB, and (2) eliminate the risk of therapy-induced second malignancies.

Cytogenetic evidence for involvement of erythroid and granulocyte/macrophage progenitors in an infant with monosomy 7 syndrome presenting de novo

Monosomy 7 presenting as a myelodysplastic syndrome following radiation and chemotherapy has been reported to involve a stem cell capable of both erythroid and granulocyte/macrophage differentiation. To determine if monosomy 7 presenting de novo also involves a multipotential stem cell, we examined mitoses from individual colony-forming units (CFU)-GM and burst-forming units (BFU)-E colonies derived from semisolid cultures of marrow from an infant with this disorder. Direct cytogenetic analysis of bone marrow cells disclosed the characteristic 45,XY,-7 karyotype in 32 of 35 abnormal metaphases. Metaphases were obtained from 63 (73%) of 85 CFU-GM and BFU-E colonies (median metaphases per colony = 4, range = 1-21), with well-banded analyzable chromosome spreads available for 15 of the colonies with metaphases. The monosomy 7 karyotype was present in all 14 metaphases from ten BFU-E colonies and in all seven metaphases from five CFU-GM colonies. These results indicate that the monosomy 7 karyotype can originate in haematopoietic stem cells with both erythroid and granulocyte/macrophage differentiative potential.

Juvenile monosomy 7 syndrome: evidence that the disease originates in a pluripotent hemopoietic stem cell

The present study was undertaken to investigate the hemopoietic cell from which malignant change evolves in juvenile dyshemopoiesis with monosomy 7. Two male patients, aged 18 and 5 months, were studied using progenitor assays combined with cytogenetics. Both had hepatosplenomegaly, cytopenias and a cellular marrow. The karyotype in direct marrow was 45,XY-7/47,XY,+8/46,XY in patient 1 and 45,XY,-7/46,XY in patient 2. Patient 1 received chemotherapy but developed acute nonlymphocytic leukemia after 17 months and died 20 months after diagnosis. During this time marrow metaphases with 45,XY,-7 increased to 100% (25/25). Patient 2 received an allogeneic marrow transplant 4 months after diagnosis which did not engraft. In both patients progenitors of both small (CFU-E) and large (BFU-E) erythroid colonies were present at normal frequencies. However, the colonies produced were small and poorly hemoglobinized with some erythropoietin-independent maturation. Progenitors of large granulocyte/macrophage colonies (CFU-GM) were present at an elevated frequency in the marrow of patient 1 and in the blood all progenitor classes were markedly increased. Cytogenetic analysis of colonies from this patient showed BFU-E to be 45,XY,-7 or 47,XY,+8 and CFU-GM to be 45,XY,-7 or 47,XY,+8 or 46,XY. In patient 2, most BFU-E were 45,XY,-7, although a few were 46,XY. These data indicate that malignant change in this disease involves hemopoietic stem cells capable of erythroid and in at least some cases, myeloid differentiation.