Low frequency of FLT3 gene internal tandem duplication and activating loop mutation in therapy-related acute myelocyticleukemia and myelodysplastic syndrome

FLT3 gene internal tandem duplication (ITD) and activating loop mutations (D835) were determined in 22 cases of therapy-related acute myelocytic leukemia/myelodysplastic syndrome (t-AML/MDS) and 102 cases of de novo AML/MDS. In t-AML/MDS, FLT3 ITD was absent, and D835 was found in only one case of therapy-related acute promyelocytic leukemia (APL). In de novo AML/MDS, however, FLT3 ITD and D835 were significantly more frequent (28 of 102 cases, P=0.024) and were associated with high peripheral blood and marrow blast counts. Our results suggest that different pathogenetic pathways might be involved in t-AML/MDS and de novo AML/MDS.     

Therapy-related myelodysplastic syndrome: morphologic subclassification may not be clinically relevant

In practice, cases of therapy-related myelodysplastic syndrome (t-MDS) are often classified according to morphologic schemes used for de novo MDS. However, there are few data addressing the appropriateness of such classification. We studied 155 patients with therapy-related acute myeloid leukemia (t-AML)/t-MDS to determine whether subclassification by the World Health Organization (WHO) criteria for de novo MDS provides prognostic information in t-MDS. In addition, we assessed whether cytogenetic stratification by the International Prognostic Scoring System (IPSS) guidelines or karyotypic complexity was prognostically important. We found no differences in median survival times among patients classified into the different WHO subgroup of MDS or according to their bone marrow blast percentage; our results indicate a uniformly poor outcome in t-MDS regardless of morphologic classification. However, significant survival differences correlated with cytogenetic stratification according to IPSS guidelines and/or karyotypic complexity. We found only a borderline difference in median survival of patients with an initial t-MDS diagnosis compared with patients with an initial t-AML diagnosis.     

Myelodysplastic syndrome with inv(3)(q21q26.2) or t(3;3)(q21;q26.2) has a high risk for progression to acute myeloid leukemia

Acute myeloid leukemia (AML) with inv(3) (q21q26.2) or t(3;3)(q21;q26.2) is a distinct subtype in the World Health Organization classification. The natural history of myelodysplastic syndrome (MDS) associated with these cytogenetic aberrations is poorly understood. We studied 17 MDS (11 de novo and 6 therapy related) and 3 chronic myelomonocytic leukemia (CMML) cases associated with inv(3) (q21q26.2) or t(3;3)(q21;q26.2). The de novo cases were further classified as refractory cytopenia with multilineage dysplasia (n = 8) and refractory anemia with excess blasts (n = 3). Isolated inv(3)/t(3;3) was identified in 4 cases, whereas -7/7q (n = 13) and -5/5q (n = 6) were common additional aberrations. Nineteen patients died, including 13 in whom the disease progressed to AML after a median of 7 months. Median survival for patients with de novo disease was similar to that for patients with therapy-related MDS (13 vs 17.5 months). MDS or CMML with inv(3)/t(3;3) are aggressive diseases with a high risk of progression to AML.     

RAS, FLT3, and TP53 mutations in therapy-related myeloid malignancies with abnormalities of chromosomes 5 and 7

Oncogenic mutations in the KRAS2, NRAS, or FLT3 gene are detected in more than 50% of patients with de novo acute myeloid leukemia (AML). RAS mutations are also prevalent in de novo myelodysplastic syndrome (MDS), especially chronic myelomonocytic leukemia and juvenile myelomonocytic leukemia. However, few studies have examined these genetic lesions in therapy-related myeloid malignancies. Monosomy 7/del(7q) and monosomy 5/del(5q) represent the most common cytogenetic abnormalities in therapy-related MDS and AML (t-MDS/t-AML) and are strongly associated with prior exposure to alkylating agents. Mutational analysis of bone marrow specimens from a well-characterized cohort of 26 t-MDS/t-AML patients with abnormalities of chromosomes 5 and/or 7 revealed 3 with RAS mutations. Further analyses of 23 of these cases uncovered one FLT3 internal tandem duplication and five TP53 mutations. The four patients with RAS or FLT3 mutations had monosomy 7, including one with abnormalities of chromosomes 5 and 7. One specimen demonstrated mutations in both KRAS2 and TP53. RAS and FLT3 mutations, which are thought to stimulate the proliferation of leukemia cells, appear to be less common in t-MDS/t-AML than in de novo AML, whereas TP53 mutations are more frequent.     

t(8;21)(q22;q22) in blast phase of chronic myelogenous leukemia

The blast phase of chronic myelogenous leukemia (CML) frequently is associated with cytogenetic evidence of clonal evolution, defined as chromosomal aberrations in addition to the t(9;22)(q34;q11.2). We identified the t(8;21)(q22;q22) and other cytogenetic abnormalities by conventional cytogenetics and fluorescence in situ hybridization in 2 patients with t(9;22)-positive CML at the time of blast phase. The t(8;21), which typically is associated with a distinct subtype of de novo acute myeloid leukemia (AML) carrying the aml1/eto fusion gene, was accompanied by increased bone marrow myeloblasts (33%) in case 1 and extramedullary myeloid sarcoma in case 2, suggesting its possible role in disease progression. In case 1, the leukemic cells in aspirate smears had salmon-colored cytoplasmic granules, and immunophenotypic studies showed that the blasts expressed CD19. These findings suggest that the pathologic features of blast phase CML with the t(8;21) resemble those of de novo AML with the t(8;21).     

Myelodysplastic syndrome/acute myeloid leukemia with t(3;21)(q26.2;q22) is commonly a therapy-related disease associated with poor outcome

The t(3;21)(q26.2;q22) translocation is rare in cases of myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML). We studied 17 patients with MDS/AML associated with t(3;21) and compared them with 17 patients with MDS associated with inv(3) (q21q26.2)/t(3;3)(q21;q26.2), because these entities share 3q26 locus abnormalities. The t(3;21) group included 9 men and 8 women, with a median age of 62 years (range, 13-81 years). One case was de novo AML and 16 cases were therapy-related, including 12 MDS (blasts, <15%) and 4 AML (blasts, 33%-50%). All patients had multilineage dysplasia, whereas none had thrombocytosis. Additional cytogenetic aberrations were identified in 12 cases, including -7/7q (n = 9) and a complex karyotype (n = 7). All patients died, with 1- and 2-year survival rates of 35% and 6%, respectively. Although multilineage dysplasia and frequent association with -7/7q were similar in both groups, MDS/AML cases associated with t(3;21) have a higher frequency of therapy-related disease and shorter survival times, suggesting that they are distinct from MDS/AML cases associated with inv(3)/t(3;3).     

MDS/AML-associated cytogenetic abnormalities in multiple myeloma and monoclonal gammopathy of undetermined significance: evidence for frequent de novo occurrence and multipotent stem cell involvement of del(20q)

Multiple myeloma (MM) and monoclonal gammopathy of undetermined significance (MGUS) are characterized cytogenetically by 14q32 rearrangements, -13/13q-, and various trisomies. Occasionally, karyotypic patterns characteristic of myelodysplastic syndrome (MDS)/acute myeloid leukemia (AML) occur in MM, often signifying therapy-related (t)-MDS/t-AML. Comparison of cytogenetic features in all published MMs (n = 993) and t-MDS/t-AML post-MM (n = 117) revealed significant differences in complexity and ploidy levels and in most genomic changes. Thus, these features often can be used to distinguish between MM and t-MDS/t-AML. Rarely, myeloid-associated aberrations are detected in MM without any signs of MDS/AML. To characterize such abnormalities in MM/MGUS, we ascertained all 122 MM and 26 MGUS/smoldering MM (SMM) cases analyzed in our department. Sixty-six (54%) MMs and 8 (31%) MGUS/SMMs were karyotypically abnormal, of which 6 (9%) MMs and 3 (38%) MGUS/SMMs displayed myeloid abnormalities, that is, +8 (1 case) and 20q- (8 cases) as the sole anomalies, without any evidence of MDS/AML. One patient developed AML, whereas no MDS/AML occurred in the remaining 8 patients. In one MGUS with del(20q), fluorescence in situ hybridization analyses revealed its presence in CD34+CD38- (hematopoietic stem cells), CD34+CD38+ (progenitors), CD19+ (B cells), and CD15+ (myeloid cells). The present data indicate that 20q- occurs in 10% of karyotypically abnormal MM/MGUS cases and that it might arise at a multipotent progenitor/stem cell level.     

dic(5;17): A recurring abnormality in malignant myeloid disorders associated with mutations of TP53

We have identified three unbalanced translocations involving chromosomes 5 and 17, der(5)t(5;17), der(17)t(5;17), and dic(5;17), in the malignant cells from 17 patients with myeloid neoplasms. Six patients had a primary myelodysplastic syndrome (MDS) or acute myeloid leukemia (AML) de novo; ten patients had therapy-related MDS and/or AML (t-MDS/t-AML), and one patient had chronic myelogenous leukemia in myeloid blast phase. Two of the six patients with MDS or AML de novo had extensive exposure to industrial solvents, and one patient had Seckel syndrome. The primary diagnoses for the ten patients with t-MDS/t-AML were breast carcinoma and Hodgkin's disease in two patients each, and non-Hodgkin's lymphoma, multiple myeloma, chronic lymphocytic leukemia, ovarian carcinoma, thyroid carcinoma, and rhabdomyosarcoma in one patient each. Four patients had received both prior chemotherapy and radiotherapy, four others received prior chemotherapy only, and the remaining two patients only prior radiotherapy. Fluorescence in situ hybridization of centromere-specific probes for chromosomes 5 and 17 revealed that a dicentric rearrangement was the most common (13/16 patients examined). The genetic consequences of these chromosomal rearrangements are partial monosomy for 5q and 17p. Two of six patients examined had point mutations in TP53, suggesting that loss of function of TP53 in addition to loss of a tumor suppressor gene on 5q may be involved in the pathogenesis of the malignant disease in some of these patients. Genes Chromosomes Cancer 20:282–291, 1997. © 1997 Wiley-Liss, Inc.     

Translocation (3;8)(q26;q24): a recurrent chromosomal abnormality in myelodysplastic syndrome and acute myeloid leukemia

We identified a reciprocal translocation between chromosomes 3 and 8, with breakpoints at bands 3q26 and 8q24, in five patients with myelodysplastic syndrome (MDS) or acute myeloid leukemia (AML). The t(3;8)(q26;q24) was the sole cytogenetic aberration in two patients, was associated with trisomy 13 in one patient, and occurred with monosomy 7 in two patients. In three patients, the AML or MDS developed 36, 52, and 57 months following chemotherapy for soft tissue sarcoma, mantle cell lymphoma, and diffuse large B-cell lymphoma, respectively; in these three patients, the neoplasms were considered to be therapy-related. All five patients displayed marked trilineage dysplasia and variable degrees of cytopenias, with marked thrombocytosis noted in one patient and a normal platelet count in another patient. All patients were treated with combination chemotherapy; at writing, four were still alive and one had died during a follow-up period ranging from 1 to 16 months. We conclude that the t(3;8)(q26;q24) is a recurrent translocation associated with therapy-related MDS/AML or de novo AML, and is frequently associated with monosomy 7.     

Clinical and pathologic features of secondary acute promyelocytic leukemia

Acute promyelocytic leukemia (APL) is a relatively common form of acute myeloid leukemia (AML) that has an excellent prognosis. In contrast, secondary acute myeloid leukemias, including therapy-related AML and AML with myelodysplasia-related changes, have a relatively poor prognosis. We identified 9 cases of APL at our institution in which there was a history of chemotherapy, radiotherapy, chronic immunosuppression, or antecedent myelodysplastic syndrome. The clinical and pathologic findings in these cases of secondary APL were compared with the clinical and pathologic findings in cases of de novo APL. We found that secondary and de novo APL had abnormal promyelocytes with similar morphologic and immunophenotypic features, comparable cytogenetic findings, comparable rates of FMS-like tyrosine kinase mutations, and similar rates of recurrent disease and death. These data suggest that secondary APL is similar to de novo APL and, thus, should be considered distinct from other secondary acute myeloid neoplasms.     

Evaluation of chromosome 5 aberrations in complex karyotypes of patients with myeloid disorders reveals their contribution to dicentric and tricentric chromosomes, resulting in the loss of critical 5q regions

Dicentric chromosomes have often been observed in complex karyotypes in previously reported studies of therapy-related myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML). Fluorescence in situ hybridization (FISH) has now made the characterization of these rearrangements much easier. Dicentric and tricentric chromosomes were identified in 21 patients (9 MDS and 12 AML) among the 133 consecutive MDS/AML patients (17%) who had a structural or numerical aberration of chromosome 5 using conventional cytogenetic analysis. One third (7/21) of the patients had received alkylating drugs for a previously diagnosed cancer or chronic myeloproliferative disease. Loss of 5q material was identified in all 21 patients. One copy of the EGR1 (5q31) or the CSF1R (5q33 approximately q34) genes was lost in 20 of the 21 patients. Dicentric and tricentric chromosomes involving chromosome 5 are frequently observed in complex karyotypes among patients with de novo or therapy-related MDS/AML. They lead to deletions of various parts of the long arm of chromosome 5.     

Leukemias resembling acute promyelocytic leukemia, microgranular variant

Acute promyelocytic leukemia (APL) should be distinguished from other subtypes of acute myeloid leukemia (AML) because of the increased risk of disseminated intravascular coagulation (DIC) and its response to arsenic compounds and retinoids. Some cases of AML seem morphologically similar to the microgranular variant of APL (French-American-British [FAB] AML-M3v) but lack the t(15;17). We evaluated 8 cases of APL-like leukemias for subtle morphologic, cytochemical, immunophenotypic, and cytogenetic differences compared with 5 cases of promyelocytic leukemia/retinoic receptor alpha (PML/RARalpha)-positive APL (FAB AML-M3v). We also evaluated both groups for the presence of DIC. No differences among the groups were noted in blast size, chromatin pattern, nuclear morphologic features, intensity of myeloperoxidase staining, or presence of Auer rods. Immunophenotypes were similar; both types of cases lacked CD34 and HLA-DR and were CD13+ and CD33+. Two cases of APL-like leukemias also were CD56+. DIC was present in 2 patients with M3v. Our study shows that there are no definitive morphologic, cytochemical, or immunophenotypic findings that can distinguish these cases from PML/RARalpha-positive APL.     

Translocations and deletions with breakpoint on 21q are nonrandomly associated with treatment-related acute nonlymphocytic leukemia and preleukemia

Six of 70 (8.6%) consecutive cases with therapy-related acute nonlymphocytic leukemia (ANLL) or preleukemia had a translocation or deletion with a breakpoint on 21q. Such aberrations were seen in only one of 200 (0.5%) consecutive cases of de novo ANLL examined at our laboratory. The figures reflect a 17.1-fold increased incidence of 21q aberrations in therapy-related ANLL or preleukemia, compared with ANLL de novo. The difference is highly significant (p = 0.003). The increased incidence of 21q aberrations in therapy-related myelodysplastic syndromes was confirmed by literature studies. Band 21q22 was most often involved. Cases with t(8;21), which is strongly associated with the M2 variant of ANLL, or cases with i(21q), which is supposedly due to a centromeric misdivision, were not included in the count. It is concluded that the 21q aberrations are associated with treatment-related ANLL or preleukemia with at least the same degree of specificity as aberrations of #5 and #7.     

Therapy-related myelodysplastic syndrome/acute myeloid leukemia with del(7)(q22) in a patient with de novo AML

A 55-year-old Korean woman was initially diagnosed with acute myelomonocytic leukemia (AML). After induction chemotherapy was performed using cytarabine, idarubicin, and G-CSF, complete remission (CR) was subsequently achieved following reinduction chemotherapy using the same chemotherapeutic agents. Thirty-six months after the initial CR, an increase in immature cells (up to 12.0%) was observed in the patient's bone marrow. Because chromosome analysis revealed a karyotype of 46,XX,del(7)(q22) in all of the analyzed cells, the patient was diagnosed with therapy-related myelodysplastic syndrome (t-MDS). Although the patient subsequently received chemotherapy and G-CSF for neutropenia, t-MDS rapidly progressed after 3 months to therapy-related acute myeloid leukemia (t-AML). Although very rare, de novo AML can progress to a secondary MDS/AML with del(7q) after chemotherapy with cytarabine, idarubicin, and G-CSF. Further investigation into the role of genes located in 7q22 may provide more information about the mechanisms of leukemogenesis.     

Rare t(1;11)(q23;p15) in therapy-related myelodysplastic syndrome evolving into acute myelomonocytic leukemia: a case report and review of the literature

Balanced chromosome rearrangements are the hallmark of therapy-related leukemia that develops in patients treated with topoisomerase II inhibitors. Many of these rearrangements involve recurrent chromosomal sites and associated genes (11q23/MLL, 21q22.3/AML1, and 11p15/NUP98), which can interact with a variety of partner genes. One such rearrangement is the rare t(1;11)(q23;p15), which involves juxtaposition of the homeobox gene PMX1 (PRRX1) and NUP98. We report on an additional patient with t(1;11) who presented with myelodysplastic syndrome (MDS) subsequent to treatment for a pleomorphic liposarcoma. With time, the patient's disorder progressed to acute myelomonocytic leukemia with cytogenetic evidence of clonal evolution. To our knowledge, this is the first report of a patient presenting with a myelodysplastic syndrome with isolated t(1;11) (q23;p15), which evolved into therapy-related acute myeloid leukemia (t-AML). This patient is the third reported with this cytogenetic rearrangement and t-AML, and is compared with the other two reports of t(1;11)(q23;p15).     

Impact of cytogenetics on outcome of de novo and therapy-related AML and MDS after allogeneic transplantation.

Cytogenetics has an important impact on the prognosis of patients undergoing allogeneic hematopoietic stem cell transplantation (HSCT) for acute myelogenous leukemia (AML) or myelodysplastic syndromes (MDS). However, it is unclear whether currently accepted cytogenetic risk groups, which were established for patients treated mostly with standard therapy, are optimally discriminating for patients undergoing HSCT. Also, the impact of cytogenetics in the growing population of patients with therapy-related disease has not been completely elucidated. In this study, we retrospectively analyzed data on 556 patients with AML or MDS transplanted at our institution. We examined, in multivariate analyses, the contribution of cytogenetics to survival, relapse, and nonrelapse mortality for the 476 patients with de novo disease. We used these results to establish an optimal cytogenetic grouping scheme. We then applied this grouping scheme to the 80 patients with therapy-related disease. Our proposed 3-group cytogenetic classification outperformed the established grouping schemes for both de novo and therapy-related disease. When classified by this new scheme, cytogenetics was the strongest prognostic factor for overall survival in our cohort, through its impact on the risk of relapse (and not on nonrelapse mortality). After accounting for cytogenetics, patients with therapy-related AML or MDS had an equivalent outcome to those with de novo disease. This study demonstrates the impact of cytogenetics on the risk of relapse and death for patients with both de novo and therapy-related disease undergoing transplantation; it also emphasizes the necessity of using cytogenetics to stratify patients entering clinical trials, and provides a system for doing so, which can be validated in a multi-institutional database.     

Translocation (11;16)(q23;p13) acute myelogenous leukemia and myelodysplastic syndrome

The purpose of this study is to examine the relationship of t(11;16)(q23;p13) to the type of myeloproliferative disorder noted by hematopathology. Previously, t(11;16) has been reported in fewer than 20 patients, all with the diagnosis of therapy-related (secondary) acute myelogenous leukemia (sAML) or myelodysplastic syndrome (MDS). Putative involved genes are the MLL on 11q23 and CBP at 16p13. Data from The University of Texas M. D. Anderson Cancer Center (UTMDACC) Cytogenetics Laboratory revealed 3 patients with t(11;16) observed during the past 5 years. Two of the patients had a prior diagnosis of non-Hodgkin lymphoma (NHL) and had been treated with chemotherapy, which included cyclophosphamide. The other patient presented with de novo AML and no history of cancer or chemotherapy. Two of the 3 patients had t(11;16) as the sole cytogenetic abnormality. One patient had a t(11;16) clone that included t(9;21) and t(10;21) as additional changes. Translocation (11;16) has previously been reported only as being therapy-related. In this study, the t(11;16) was seen in 2 patients with previous lymphomas treated with cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP). A single patient with apparently de novo AML constitutes the first reported instance of non-treatment associated t(11;16) AML.     

21q22 balanced chromosome aberrations in therapy-related hematopoietic disorders: report from an international workshop

The International Workshop on the relationship between prior therapy and balanced chromosome aberrations in therapy-related myelodysplastic syndromes (t-MDS) and therapy-related acute leukemia (t-AL) identified 79 of 511 (15.5%) patients with balanced 21q22 translocations. Patients were treated for their primary disease, including solid tumors (56%), hematologic malignancy (43%), and juvenile rheumatoid arthritis (single case), by radiation therapy (5 patients), chemotherapy (36 patients), or combined-modality therapy (38 patients). 21q translocations involved common partner chromosomes in 81% of cases: t(8;21) (n = 44; 56%), t(3;21) (n = 16; 20%), and t(16;21) (n = 4; 5%). Translocations involving 15 other partner chromosomes were also documented with involvement of AML1(CBFA2/RUNX1), identifying a total of 23 different 21q22/AML1 translocations. The data analysis was carried out on the basis of five subsets of 21q22 cases, that is, t(8;21) with and without additional aberrations, t(3;21), t(16;21), and other 21q22 translocations. Dysplastic features were present in all 21q22 cases. Therapy-related acute myeloid leukemia (t-AML) at presentation was highest in t(8;21) (82%) and lowest in t(3;21) (37.5%) patients. Cumulative drug dose exposure scores for alkylating agents (AAs) and topoisomerase II inhibitors indicated that t(3;21) patients received the most intensive therapy among the five 21q22 subsets, and the median AA score for patients with secondary chromosome 7 aberrations was double the AA score for the entire 21q22 group. All five patients who received only radiation therapy had t(8;21) t-AML. The median latency and overall survival (OS) for 21q22 patients were 39 and 14 months (mo), compared to 26 and 8 mo for 11q23 patients, 22 and 28 mo for inv(16), 69 and 7 mo for Rare recurring aberrations, and 59 and 7 mo for Unique (nonrecurring) balanced aberration (latency P < or = 0.016 for all pairwise comparisons; OS, P < or = 0.018 for all pairwise comparisons). The percentages of 21q22 patients surviving 1 year, 2 years, and 5 years were 58%, 33%, and 18%, respectively. Noticeable differences were observed in median OS between 21q22 patients (n = 7) receiving transplant (BMT) (31 mo) compared to 21q22 patients who received intensive non-BMT therapy (n = 46) (17 mo); however, this was nonsignificant because of the small sample size (log-rank, P = 0.33). t-MDS/t-AML with balanced 21q22 aberrations was associated with prior exposure to radiation, epipodophyllotoxins, and anthracyclines, dysplastic morphologic features, multiple partner chromosomes, and longer latency periods when compared to 11q23 and inv(16) t-MDS/AML Workshop subgroups. In general, patients could be divided into two prognostic risk groups, those with t(8;21) (median OS, 19 mo) and those without t(8;21) (median OS, 7 mo) leukemia (log-rank, P = 0.0007).     

Massive hyperdiploidy and tetraploidy in acute myelocytic leukemia and myelodysplastic syndrome

Massive hyperdiploidy (>50 chromosomes) and tetraploidy (4n) are rare cytogenetic abnormalities in myelocytic malignancies, and their significance is unknown. We report on 11 patients with acute myelocytic leukemia (AML) and two patients with a myelodysplastic syndrome (MDS) with massive hyperdiploidy (10 patients) or tetraploidy (3 patients) seen at our institution over a 12-year period. Eleven patients were male and two were female. Age range was 44-84 years (median, 70 years). Only one AML patient had a previous MDS, and no patient had therapy-related disease. One or more copies of chromosomes 8 and 19 were gained in eight patients each; other frequently gained chromosomes included 13, 15, and 21. Eight patients had structural abnormalities in addition to chromosome gain; del(5q) was most common (five patients). Eleven patients received induction chemotherapy, but only four achieved complete remission. Survival ranged from 1 to 22 months, with a median of 6 months. We conclude that massive hyperdiploidy and tetraploidy are infrequent abnormalities in AML and MDS, are seen primarily in de novo disease in older male patients and are associated with a low remission rate and short survival. Massive hyperdiploidy and tetraploidy define a prognostically unfavorable cytogenetic group in de novo AML.