Chromosomal loss and deletion are the most common mechanisms for loss of heterozygosity from chromosomes 5 and 7 in malignant myeloid disorders.

We have examined a population of patients with acute myeloid leukemia (AML) or myelodysplastic syndrome (MDS) for loss of heterozygosity of polymorphic markers on chromosomes 5 and 7. The rationale for this study was the observation that the majority of patients with therapy-related leukemia (t-AML or t-MDS), resulting from cytotoxic treatment for prior malignancies, have loss of chromosome 5 and/or 7 or deletions involving the long arms of one or both of these chromosomes. This cytogenetic finding suggested that tumor-suppressor genes, important in the development of AML, may be located in these chromosomal regions. We analyzed a total of 60 patients, 43 with primary MDS/AML de novo and 17 with t-MDS/t-AML. Leukemia cells were evaluated for restriction fragment length polymorphisms (RFLPs). Leukemia cell genotypes were compared with lymphoblastoid cell genotypes from the same patients. Two cases of loss of heterozygosity were identified from chromosomes lacking visible deletions: one involving chromosome 5 in a patient with AML de novo who had a visible deletion of 5q at a later stage of the disease, and one involving chromosome 7 in a patient with t-AML. We conclude that allele loss from loci on chromosomes 5 and 7 in MDS/AML, when it occurs, usually results from major deletion or simple chromosome loss, rather than from mitotic recombination or chromosome loss with duplication of the remaining homologue.     

Therapy-related myelodysplastic syndrome with trisomy 1q due to der(1;7) and megakaryoblastic proliferation developing during complete remission of therapy-related acute myeloid leukemia with t(8;21)

Therapy-related acute myeloid leukemia (t-AML) with t(8;21) and therapy-related myelodysplastic syndrome (t-MDS) with trisomy 1q due to der(1;7) developed in the same patient with T-cell lymphoma at intervals of six years. After the development of t-MDS with trisomy 1q, during complete remission of t-AML, the number of megakaryoblasts increased to maximally 74% of leukocytes in the blood. This is a very rare case of two separate therapy-related myeloid malignancies (early t-AML and late t-MDS) and is also a notable case of t-MDS with trisomy 1q due to der(1;7) accompanied by megakaryoblastic proliferation.     

Different genetic pathways in leukemogenesis for patients presenting with therapy-related myelodysplasia and therapy-related acute myeloid leukemia

Development of myelodysplasia (MDS) with subsequent progression to acute myeloid leukemia (AML) is an example of the multistep process of malignant transformation in which each step often relates to genetic abnormalities that can be directly seen as chromosomal aberrations. Therapy-related MDS and AML (t-MDS and t-AML) may serve as an ideal model for a study of the genetic evolution of MDS and AML because chromosomal abnormalities are observed in most cases and because the disease is often diagnosed early due to a close patient follow-up. The cytogenetic characteristics at diagnosis were studied in 137 consecutive cases of t-MDS and t-AML, including 22 new cases, and correlated with the clinical characteristics and the course of the disease. Balanced translocations to chromosome bands 11q23 and 21q22 represent primary steps in pathways leading directly to overt t-AML. Specific chromosomal deletions or losses, on the other hand, represent primary or secondary events in alternative pathways leading to t-MDS with potential for subsequent transformation to overt t-AML. Loss of a whole chromosome 7 (-7) or deletion of its long arm (7q-) and deletion of the long arm of a chromosome 5 (5q-) were the most frequent primary abnormalities significantly related to t-MDS. Loss of a whole chromosome 5 (-5) was also a primary event, but surprisingly, was observed equally in t-MDS and in t-AML. Deletion of chromosome 13, including bands q13q14, was another less common primary aberration of t- MDS. Except for -7 and del(13q), these primary aberrations were most often observed together with secondary abnormalities. These included balanced aberrations involving band 3q26 and various deletions of chromosome 3, a gain of a whole chromosome 8, deletions of the short arm or loss of chromosomes 12 and 17, loss of a whole chromosome 18, and deletions of the short arm of chromosome 21. Deletions or loss or chromosomes 5 and 7 were significantly associated with previous therapy with alkylating agents (P = .002), and balanced translocations to chromosome bands 3q26, 11q23, and 21q22 were significantly associated with previous therapy with drugs targeting DNA-topoisomerase II (P < .00005). Other characteristic aberrations were not related to any specific type of therapy. The molecular changes believed to contribute to the development of t-MDS and t-AML have been identified for many of these chromosomal abnormalities.     

Secondary clonal cytogenetic abnormalities following successful treatment of acute promyelocytic leukemia

To identify patients who developed secondary clonal cytogenetic aberrations (CCA) following therapy for acute promyelocytic leukemia (APL), we retrospectively analyzed cytogenetic results from 123 patients diagnosed with APL between 1995 and 2007, who had ongoing cytogenetic analysis undertaken in our laboratory. During follow‐up for APL we identified 12 patients (9.8%) who developed CCA, not detected at diagnosis of APL and unrelated to their original APL karyotype. All patients had received all‐trans retinoic acid (ATRA) and chemotherapy and were in complete remission for APL when secondary CCA were identified. The median latency period between diagnosis of APL and emergence of secondary CCA was 27.5 months (range: 2–54 months). To date, four patients with CCA have been diagnosed with therapy‐related myelodysplastic syndrome (t‐MDS)/acute myeloid leukemia (t‐AML), giving a median t‐MDS/AML free survival of 78 months, with follow‐up ranging between 20 and 136 months from APL diagnosis. Three patients have died: two patients died of t‐AML and another developed relapsed APL with persistence of his secondary clone but no diagnosis of t‐MDS/AML and died from transplant‐related complications. Two patients are alive with t‐MDS. Seven patients with CCA are alive with no morphological evidence of MDS at the time of their last known follow‐up; thus median survival has not been reached. The appearance of these abnormalities in the absence of morphological evidence of MDS in the majority of patients is unusual, and highlights the importance of continued cytogenetic follow‐up in these patients. Am. J. Hematol., 2009. © 2009 Wiley‐Liss, Inc.     

Acute myelomegakaryocytic leukemia developed from myelodysplastic syndrome after chemotherapy against complicated small cell lung cancer]

A patient with acute myelomegakaryocytic leukemia (AMMgL), which developed from myelodysplastic syndrome (MDS) after chemotherapy against complicated small cell lung cancer, is reported. The patient was a 66 year-old male, who first presented with moderate macrocytic anemia. Bone marrow aspiration showed absolute erythroid hypoplasia and morphological abnormalities were found in erythroid, granuloid and megakaryocytic lineage cells. Iron utilization studies using radioisotope showed ineffective hematopoiesis. He was diagnosed as having MDS (refractory anemia) and treated with prednisolone, fluoxymesterone, and transfusions. After 3 years, small cell lung cancer was found, but he achieved complete remission with chemotherapy. Since then, pancytopenia progressed with myelofibrosis. Abnormal blasts were found in peripheral blood and gradually increased. He finally died from a blastic crisis resulting in gastric bleeding. The blasts were peroxidase negative, platelet peroxidase positive (10%), and glycoprotein II b/III a antibody positive, indicating megakaryoblasts.     

Primary myelodysplastic syndrome in children--clinical, hematological and histomorphological profile from a tertiary care centre in India

We describe the clinical, hematological and histomorphological features in children of primary myelodysplastic syndrome (MDS) seen at the All India Institute of Medical Sciences over three years (Jan 2001-Jan 2004). Twenty-one patients of primary MDS aged 17 year or less were classified using the latest proposed WHO classification for Pediatric MDS. The median age was 9 years with male predominance (80%). Pallor was present in all the cases while fever and bleeding diathesis was present in more than 50% of the cases. Morphological assessment of the peripheral blood showed macrocytosis in 50%, pancytopenia in 15% and blast cells in 45% of cases. A complete analysis of clinical features in conjunction with the bone marrow profile revealed 8 cases of refractory cytopenia (RC), 3 cases of refractory anemia with excess blasts (RAEB), 5 cases of refractory anemia with excess blasts in transformation (RAEB-T), 4 cases of Juvenile myelomonocytic leukemia (JMML) and a solitary cases of acute myeloid leukemia (AML) in Downs syndrome.These children were followed up from 1-36 months (mean 15 months). Three patients of RAEB-T progressed to AML within 3-4 months. RC had the best prognosis and all are alive and under regular follow up. The solitary case of AML of Downs syndrome died 1.5 months after initial diagnosis. All 3 cases of RAEB are under regular follow-up and doing well. Three cases of RAEB-T died (all had progressed to AML); the remaining 2 cases were lost to follow up. Of the 4 cases of JMML 1 died within 6 months of diagnosis; the other 3 cases are under regular follow up of whom 1 has a progressively increasing blast count.We conclude that the latest proposed WHO classification for Pediatric MDS can be successfully applied to all cases of primary MDS.     

Therapy-related acute myeloid leukemia after single-agent treatment with fludarabine for chronic lymphocytic leukemia

A 70-year-old man with B-cell chronic lymphocytic leukemia (CLL) received single-agent treatment with the purine analogue fludarabine, which led to complete remission. After 8 years, he presented with pancytopenia. Marrow examination showed acute myeloid leukemia (AML) with trilineage myelodysplasia (MDS). Cytogenetic analysis showed an unbalanced der(1;7)(p10;q10) that resulted effectively in deletion 7q; confirming the diagnosis of therapy-related AML (t-AML). No residual CLL was present. Together with previous reports of secondary cancers after fludarabine treatment and the association of monosomy 7/7q- with another purine analogue azathioprine, results suggest that t-AML might develop after fludarabine therapy.     

Serial Morphologic Observation of Bone Marrow in Aplastic Anemia in Children

Recent reports of myelodysplastic syndrome/acute myeloid leukemia (t-MDS/AML) developing after treatment with immunosuppressants and granulocyte colony-stimulating factor (G-CSF) has raised the question of whether previously unrecognized myelodysplastic features had been present or whether actual transformation had occurred. We undertook a multi-institutional study of 112 children with aplastic anemia diagnosed between 1976 and 1996 and then treated with immunosuppressants with or without G-CSF. In each case, bone marrow specimens were tested at study entry and every 6 months for 3 years to detect t-MDS/AML as defined by morphologic and molecular/cytogenetic criteria. As of December 2001, all eligible patients had been followed for a median of 3 years. Morphologic abnormalities were found in 17 cases. The patients in 4 of these cases had clonal cytogenetic abnormalities and received MDS diagnoses. The morphologic features of the patients with and without clonal cytogenetic abnormalities were indistinguishable. However, the mast cell content was lower in cases with cytogenetic abnormalities than in cases without them. An elucidation of the role of mast cells may provide information about the differences between aplastic anemia and MDS or about the transition of aplastic anemia to MDS.     

Sacroiliitis as an Initial Manifestation of Acute Myelogenous Leukemia

Sacroiliitis is the most pathognomonic and earliest manifestation of ankylosing spondylitis. We herein report a 28-year-old female patient who presented with sacroiliitis as an initial manifestation of acute myelogenous leukemia (AML). She had a 3-month history of anemia and walking difficulty. Bone marrow findings revealed an increase of blasts with trilineage dysplasia. Although she was initially diagnosed with myelodysplastic syndrome (MDS), blasts rapidly increased and AML developed 1 month after the diagnosis of MDS with Sacroiliitis. Induction chemotherapy failed to induce a complete remission of AML, but it did effectively treat the sacroiliitis. However, the sacroiliitis relapsed when the leukemia cells progressed thereafter. Oral corticosteroids helped ameliorate the sacroiliitis. She underwent bone marrow transplantation (BMT) from an HLA-identical sister during a nonremission period; however, the leukemic cells began to rapidly increase from day 30 after BMT. The close relationship between the occurrence of sacroiliitis and AML suggested that autoimmune sacroiliitis was a paraneoplastic phenomenon of AML in this patient. Although autoimmune disorders develop in a substantial number of MDS patients, they are rarely observed in de novo AML. No previous report has described sacroiliitis as the initial manifestation of de novo AML.     

Therapy-related leukemia and myelodysplasia: susceptibility and incidence

Therapy-related myelodysplastic syndrome/acute myeloid leukemia (t-MDS/AML) is an increasingly recognized treatment complication in patients treated with radiotherapy or chemotherapy for previous hematologic malignancies or solid tumors. Distinct clinical entities have been described according to the primary treatment, corresponding to defined genetic lesions. Chromosome 7 and/or 5 losses or deletions are typical of alkylating agent-induced AML, while development of t-AML with balanced translocations involving chromosome bands 11q23 and 21q22 has been related to previous therapy with drugs targeting DNA-topoisomerase II. In addition, antimetabolites, and in particular the immunosuppressant azathioprine, have been shown to induce defective DNA-mismatch repair. This could promote survival of misrepaired cells giving rise to the leukemic clone. Individual predisposing factors, including polymorphisms in detoxification and DNA repair enzymes have been identified. Their combination may significantly increase the risk of t-MDS/AML. Among patients with hematologic malignancies, long-term survivors of Hodgkin's lymphoma are exposed to an increased risk of t-MDS/AML, particularly when receiving MOPP-based, and escalated BEACOPP regimens, and when alkylators are combined with radiotherapy. Patients with Hodgkin's and non-Hodgkin's lymphoma are at highest risk when total body irradiation followed by autologous stem cell transplantation is used as rescue or consolidation therapy. The addition of granulocyte-colony-stimulating factor and radiotherapy plays a significant role in t-AML following treatment of children with acute lymphoblastic leukemia. In non-hematologic malignancies, treatment for breast cancer and germ-cell tumors has been associated with a 1-5% lifetime risk of both lymphoid as well as myeloid leukemia. In all cases the risk of t-MDS/AML drops sharply by 10 years after treatment.     

REVIEW: Recent advances in the diagnosis and classification of myeloid neoplasms – comments on the 2008 WHO classification

The fourth edition of the World Health Organization (WHO) classification of myeloid neoplasms refined the criteria for some previously described myeloid neoplasms and recognized several new entities based on recent elucidation of molecular pathogenesis, identification of new diagnostic and prognostic markers, and progress in clinical management. Protein tyrosine kinase abnormalities, including translocations or mutations involving ABL1, JAK2, MPL, KIT, PDGFRA, PDGFRB, and FGFR1, have been used as the basis for classifying myeloproliferative neoplasms (MPN). Two new entities - refractory cytopenia with unilineage dysplasia and refractory cytopenia of childhood have been added to the group of myelodysplastic syndromes (MDS), and ‘refractory anemia with excess blasts-1’ has been redefined to emphasize the prognostic significance of increased blasts in the peripheral blood. A list of cytogenetic abnormalities has been introduced as presumptive evidence of MDS in cases with refractory cytopenia but without morphologic evidence of dysplasia. The subgroup ‘acute myeloid leukemia (AML) with recurrent genetic abnormalities’ has been expanded to include more molecular genetic aberrations. The entity ‘AML with multilineage dysplasia’ specified in the 2001 WHO classification has been renamed ‘AML with myelodysplasia-related changes’ to include not only cases with significant multilineage dysplasia but also patients with a history of MDS or myelodysplasia-related cytogenetic abnormalities. The term ‘therapy-related myeloid neoplasms’ is used to cover the spectrum of disorders previously known as t-AML, t-MDS, or t-MDS/MPN occurring as complications of cytotoxic chemotherapy and/or radiation therapy. In this review, we summarize many of these important changes and discuss some of the diagnostic challenges that remain.     

Rearrangements of the MLL gene in therapy-related acute myeloid leukemia in patients previously treated with agents targeting DNA- topoisomerase II

Chromosome band 11q23 is frequently involved in acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL) de novo, as well as in myelodysplastic syndromes (MDS) and lymphoma. Five percent to 15% of patients treated with chemotherapy for a primary neoplasm develop therapy-related AML (t-AML) that may show rearrangements, usually translocations involving band 11q23 or, less often, 21q22. These leukemias develop after a relatively short latent period and often follow the use of drugs that inhibit the activity of DNA-topoisomerase II (topo II). We previously identified a gene, MLL (myeloid-lymphoid leukemia or mixed-lineage leukemia), at 11q23 that is involved in the de novo leukemias. We have studied 17 patients with t-MDS/t-AML, 12 of whom had cytogenetically detectable 11q23 rearrangements. Ten of the 12 t-AML patients had received topo II inhibitors and 9 of these, all with balanced translocations of 11q23, had MLL rearrangements on Southern blot analysis. None of the patients who had not received topo II inhibitors showed an MLL rearrangement. Of the 5 patients lacking 11q23 rearrangements, some of whom had monoblastic features, none had an MLL rearrangement, although 4 had received topo II inhibitors. Our study indicates that the MLL gene rearrangements are similar both in AML that develops de novo and in t-AML. The association of exposure to topo II- reactive chemotherapy with 11q23 rearrangements involving the MLL gene in t-AML suggests that topo II may play a role in the aberrant recombination events that occur in this region both in AML de novo and in t-AML.     

t(3;21)(q26;q22): a recurring chromosomal abnormality in therapy- related myelodysplastic syndrome and acute myeloid leukemia

We have identified an identical reciprocal translocation between the long arms of chromosomes 3 and 21 with breakpoints at bands 3q26 and 21q22, [t(3;21)(q26;q22)], in the malignant cells from five adult patients with therapy-related myelodysplastic syndrome (t-MDS) or acute myeloid leukemia (t-AML). Primary diagnoses were Hodgkin's disease in two patients and ovarian carcinoma, breast cancer, and polycythemia vera in one patient each. Patients had been treated with chemotherapy including an alkylating agent for their primary disease 1 to 18 years before the development of t-MDS or t-AML. We have not observed the t(3;21) in over 1,500 patients with a myelodysplastic syndrome or acute myeloid leukemia arising de novo or in over 1,000 patients with lymphoid malignancies. We have previously reported that the t(3;21) occurs in Philadelphia chromosome-positive chronic myelogenous leukemia (CML). Thus, the t(3;21) appears to be limited to t-MDS/t-AML and CML, both of which represent malignant disorders of an early hematopoietic precursor cell. These results provide a new focus for the study of therapy-related leukemia at the molecular level.     

Primary myelodysplastic syndrome in children—clinical,hematological and histomorphological profile from a tertiary care centre in India

We describe the clinical, hematological and histomorphological features in children of primary myelodysplastic syndrome (MDS) seen at the All India Institute of Medical Sciences over three years (Jan 2001–Jan 2004). Twenty-one patients of primary MDS aged 17 year or less were classified using the latest proposed WHO classification for Pediatric MDS. The median age was 9 years with male predominance (80%). Pallor was present in all the cases while fever and bleeding diathesis was present in more than 50% of the cases. Morphological assessment of the peripheral blood showed macrocytosis in 50%, pancytopenia in 15% and blast cells in 45% of cases. A complete analysis of clinical features in conjunction with the bone marrow profile revealed 8 cases of refractory cytopenia (RC), 3 cases of refractory anemia with excess blasts (RAEB), 5 cases of refractory anemia with excess blasts in transformation (RAEB-T), 4 cases of Juvenile myelomonocytic leukemia (JMML) and a solitary cases of acute myeloid leukemia (AML) in Downs syndrome.

These children were followed up from 1–36 months (mean 15 months). Three patients of RAEB-T progressed to AML within 3–4 months. RC had the best prognosis and all are alive and under regular follow up. The solitary case of AML of Downs syndrome died 1.5 months after initial diagnosis. All 3 cases of RAEB are under regular follow-up and doing well. Three cases of RAEB-T died (all had progressed to AML); the remaining 2 cases were lost to follow up. Of the 4 cases of JMML 1 died within 6 months of diagnosis; the other 3 cases are under regular follow up of whom 1 has a progressively increasing blast count.

We conclude that the latest proposed WHO classification for Pediatric MDS can be successfully applied to all cases of primary MDS.     

Myelodysplastic Syndrome Progresses Rapidly Into Erythroleukemia Associated With Synchronous Double Cancers of the Stomach and the Papilla of Vater

Patients with myelodysplastic syndrome (MDS) show a relatively high incidence of developing cancers. However, it is extremely rare that synchronous double cancers develop in an MDS patient. We report a case of MDS that progressed rapidly into erythroleukemia (M6 by French-American-British classification) complicated by gastric cancer and carcinoma of the papilla of Vater. A 66-year-old man was admitted because of pancytopenia with peripheral blasts. A diagnosis of MDS (with refractory anemia with excess of blasts in transformation [RAEB-T]) was made by bone marrow examination. Chromosome analysis revealed 46,XY. An early gastric cancer was also diagnosed by endoscopic examination. The peripheral blasts gradually proliferated and the disease progressed to M6. A chromosome abnormality 46,XY,del(1)(q42) was detected at the leukemic transformation. A CAG (low-dose cytarabine and aclarubicin in combination with granulocyte colony-stimulating factor) regimen was started as a remission-induction therapy. However, obstructive jaundice developed and a marked dilatation of bile ducts was observed by abdominal computed tomography (CT). A carcinoma of the papilla of Vater was detected by endoscopy. As remission was achieved and the pancytopenia improved, the patient subsequently underwent a surgical jejuno-choledochostomy to manage the jaundice. However, the leukemia relapsed thereafter and additional chromosome abnormalities including der(5)t(5;10)(p15:q11) were observed.     

Detection of t(3 ; 21) (q26 ; q22) with AML1/EVI1 mRNA during progression of myelodysplastic syndrome to acute myeloid leukemia]

A 74-year-old woman had myelodysplastic syndrome (MDS) in 1986. In June 1994, she suffered exacerbation of pancytopenia with no chromosomal abnormalities, but AML1/EVI1 chimeric mRNA was detected by RT-PCR. Two months later, an increase in bone marrow blasts (5%) was noted, and chromosomal analysis detected t(3 ; 21) (q26 ; 22), del(7) (q22), del(11) (q23). In 1995, the marrow blasts increased to 30% and the patient died of disease progression. The AML1/EVI1 gene has been shown to cause blast crisis in chronic myelogenous leukemia. This case suggested that the AML1/EVI1 gene may be involved in the progression of MDS together with del(7) (q22) and del(11) (q23).     

Two Independent Clones in Myelodysplastic Syndrome Following Treatment of Acute Myeloid Leukemia

We describe a 55-year-old Japanese woman with therapy-related myelodysplastic syndrome (t-MDS) with 2 independent clones, t(1;2)(p36;p21) and t(11;12)(pl5;ql3). She was diagnosed with acute myeloid leukemia (AML) with cytological features of the bone marrow and peripheral blood. Cytogenetic evaluation revealed a 46,XX karyotype. She received chemotherapy and achieved complete remission (CR). Despite maintenance chemotherapy, she suffered a relapse. Chromosomal analysis showed t(1;2)(p36;p21) in 2 of 20 metaphases. At second CR, this clone transiently disappeared. Nine months later, t(1;2) (p36;p21) was detected again in 3 of 20 metaphases while the patient remained in CR. Six months later, bone marrow examination disclosed trilineage dysplasia without an excess of blasts, suggesting MDS. t(1;2)(p36;p21) was observed in 16 of 20 metaphases. The clinical course and serial cytogenetic findings were diagnostic of t-MDS. The duration of t-MDS was 6 years. During this period, persistent t(1;2)(p36;p21) and transient t(11;12)(p15;q13) were found. When t-MDS evolved toAML, cytogenetic evaluation revealed 46,XX,t(1;2)(p36;p21),del(7)(q22),add(19)(p13).     

Prediction of therapy-related acute myelogenous leukemia (AML) and myelodysplastic syndrome (MDS) after autologous bone marrow transplant (ABMT) for lymphoma

Therapy-related acute myelogenous leukemia and myelodysplastic syndrome (t-AML/MDS) are being reported with increasing frequency as a complication of ABMT for Hodgkin's disease and non-Hodgkin's lymphoma. At present there is no method available to predict who is at risk or is destined to develop this nearly universally fatal disorder. We therefore investigated whether clonal growth of cells is predictive of the development of t-AML/MDS. In a patient who developed secondary AML/MDS 18 months after ABMT, X-linked clonality analysis at the human androgen receptor locus was performed on serial banked samples, and documented transition from polyclonal to clonal hematopoiesis. Clonal cells could be identified 6 months after transplant (1 year prior to the diagnosis of t-AML/MDS), at a time when there was no morphologic or clinical evidence of disease. Clonality analysis can be predictive of the development of t-AML/MDS after ABMT and may offer important insights into associated risk factors and strategies to minimize the risk of t-AML/MDS. Am. J. Hematol. 56:45–51, 1997. © 1997 Wiley-Liss, Inc.