Chromosome abnormalities in malignant hematologic disorders

Liposomal Grb2 antisense oligodeoxynucleotide (BP1001) in patients with refractory or relapsed haematological malignancies: a single-centre, open-label, dose-escalation, phase 1/1b trial

BACKGROUND

Activating mutations of tyrosine kinases are common in leukaemias. Oncogenic tyrosine kinases use the growth factor receptor-bound protein 2 (Grb2) for signal transduction, leading to activation of mitogen-activated protein kinase (MAPK) 1 and MAPK3 (ERK2 and ERK1). We hypothesised that inhibition of Grb2 would suppress ERK1 and ERK2 activation and inhibit leukaemia progression. To inhibit Grb2, a liposome-incorporated antisense oligodeoxynucleotide that blocks Grb2 protein expression, BP1001, was developed. We report the first phase 1 findings of BP1001.

METHODS

In this single-centre, open-label, dose-escalation phase 1/1b trial, we enrolled participants (aged ≥18 years) with refractory or relapsed acute myeloid leukaemia, Philadelphia-chromosome-positive chronic myeloid leukaemia (in chronic, accelerated, or blast phase), acute lymphoblastic leukaemia, or myelodysplastic syndrome, at MD Anderson Cancer Center (Houston, TX, USA). We used a 3 + 3 dose escalation strategy, with at least three patients enrolled at each dose level. We administered BP1001 intravenously, twice weekly, for 28 days, with a starting dose of 5 mg/m2. If two or more patients developed toxic effects of grade 3 or higher, that dose level was deemed toxic. The dose was escalated if it did not produce dose-limiting toxic effects, and patients would be sequentially enrolled into cohort 2 (10 mg/m2), cohort 3 (20 mg/m2), cohort 4 (40 mg/m2), cohort 5 (60 mg/m2), or cohort 6 (90 mg/m2). After completion of monotherapy, we assessed the safety and toxicity of BP1001 (60 or 90 mg/m2) in combination with 20 mg low-dose cytarabine (twice-daily subcutaneous injections) in a phase 1b study in patients with refractory or relapsed acute myeloid leukaemia (ie, those who were refractory to at least one previous therapy regimen and no more than one previous salvage regimen). The objectives of this study were to establish the toxicity and tolerance of escalating doses of BP1001 monotherapy in patients with refractory or relapsed leukaemia, to assess the maximum tolerated dose of BP1001, and to determine the optimal biologically active dose of BP1001, defined as a 50% reduction in Grb2 expression in circulating leukaemia cells. We also aimed to assess the in-vivo pharmacokinetics of BP1001 and tumour response. The study is completed and is registered with ClinicalTrials.gov, number NCT01159028.

FINDINGS

Between July 23, 2010, and Feb 23, 2016, we enrolled and treated 39 patients, of whom 27 were assessable for dose-limiting toxicity. The first patient treated had mucositis and hand-foot syndrome, which were assessed as possibly related to BP1001 and counted as a dose-limiting toxicity. We noted no other dose-limiting toxicities, and a maximum tolerated dose was not identified. The highest tested dose of BP1001 was 90 mg/m2. The most common grade 3-4 adverse events were cardiopulmonary disorders (25 [64%] of 39 patients), and fever (including neutropenic fever) and infections (17 [44%] patients). Grade 5 adverse events were cardiopulmonary disorders (two [5%] of 39 patients), fever (including neutropenic fever) and infections (two [5%] of 39 patients), and multi-organ failure (one [3%] of 39 patients). Nine (33%) of 27 patients who had peripheral blood blasts at the start of therapy had a reduction of 50% or more in peripheral blood blasts while receiving BP1001 montherapy. Three (10%) of 29 patients who had bone marrow blasts at the start of therapy had a reduction in bone marrow blasts of 50% or more while receiving BP1001 monotherapy. Per investigator's assessment, seven (22%) of 32 patients benefited from BP1001 monotherapy and had extended cycles of treatment. Of seven patients receiving BP1001 plus low-dose cytarabine combination therapy, two had complete remission, one had complete remission with incomplete haematological recovery, and two had stable disease with no dose-limiting toxicity; one patient died and one withdrew, both because of disease progression. There were eight deaths; none were treatment related.

INTERPRETATION

BP1001 is well tolerated, with early evidence of anti-leukaemic activity in combination with low-dose cytarabine. To further explore this anti-leukaemic activity, the efficacy of BP1001 plus low-dose cytarabine combination is being investigated in an ongoing phase 2 study in patients with previously untreated acute myeloid leukaemia who are ineligible for intensive induction therapy.

FUNDING

Bio-Path Holdings Inc.

Maximizing mouse cancer models

Animal models of cancer provide an alternative means to determine the causes of and treatments for malignancy, thus representing a resource of immense potential for cancer medicine. The sophistication of modelling cancer in mice has increased to the extent that investigators can both observe and manipulate a complex disease process in a manner impossible to perform in patients. However, owing to limitations in model design and technology development, and the surprising underuse of existing models, only now are we realising the full potential of mouse models of cancer and what new approaches are needed to derive the maximum value for cancer patients from this investment.

Hematologic disorders in 13 patients with acquired trisomy 21 and 13 individuals with Down syndrome

To study the role of trisomy 21 in hematologic malignancies, we investigated the hematologic disorders of 13 patients with acquired trisomy 21 and 13 individuals with Down syndrome (DS). The most common hematologic malignancy among the patients with acquired trisomy 21 involved both granulocytic and monocytic lineages. By comparison, the hematologic disorders among the DS patients were predominantly acute lymphocytic leukemia and acute megakaryocytic leukemia. Although our sample was small, our results suggest that most patients with acquired trisomy 21 have different hematologic disorders than individuals with DS. Perhaps the role of trisomy 21 in the development of hematologic malignancy is different in constitutional trisomy 21 than it is in acquired trisomy 21.

Characteristics and outcome of patients with Philadelphia chromosome negative, bcr/abl negative chronic myelogenous leukemia

BACKGROUND

Up to 5% of patients with chronic myelogenous leukemia (CML) do not have the Philadelphia (Ph) translocation t(9;22)(q34;q11) or a bcr/abl molecular rearrangement. Although the diagnostic criteria of this entity are still under debate, there is general agreement that patients with Ph negative, bcr/abl negative CML have a severe clinical course that is not affected significantly by current treatment options.

METHODS

A population of 76 patients with bcr/abl negative CML who had received minimal or no previous therapy was characterized carefully with the intent of investigating clinical and hematologic variables and their association with survival by univariate, correlation, and multivariate analyses. A group of 73 patients with Ph negative CML who were not tested for the bcr/abl rearrangement (bcr/abl unknown) was analyzed separately and used for extension of the analysis.

RESULTS

In the bcr/abl negative patient population, the median overall survival was 24 months. At the time of the analysis, 38 patients (50%) had died, and blastic transformation preceded death in 31%. Chromosomal abnormalities were found in 30% of the 76 patients, with trisomy 8 the most common abnormality. Complex chromosomal abnormalities were rare, and monosomy 7 was not observed. Survival was not affected significantly by treatment. Multivariate analysis identified older age (> 65 years), anemia (hemoglobin < 10 g/dL), and severe leukocytosis (white blood cells > 50 x 10(9)/L) as variables with independent prognostic significance for poor survival. A prognostic scoring system stratified patients into a low-risk group (53%) and a high-risk group (47%), with median survivals of 38 months and 9 months, respectively.

CONCLUSIONS

Bcr/abl negative CML is a distinct clinical entity associated with very poor prognosis. Two risk categories are identifiable using a simple scoring system based on age, hemoglobin level, and leukocyte number.

Treatment of myeloma: recent developments

Melphalan was the first described treatment for patients with multiple myeloma in the 1960s and is still being used in clinical practice. However, the use of melphalan in combination with prednisone resulted in a median survival of only 2-3 years. Therefore, the dose of melphalan has been intensified since then (140-200 mg/m(2)). In order to diminish treatment-related morbidity and mortality due to severe myelosuppression induced by these regimens, high-dose melphalan is currently supported with autologous stem cells. Indications for high-dose therapy and the role of further intensification by performing second or allogeneic transplantations are discussed. Furthermore, new therapeutic modalities, such as inhibitors of angiogenesis, also showing direct antiproliferative, cytokine-related and immunomodulatory effects on plasma cells (thalidomide and its newer derivatives), inhibitors of the transcription factor NF-kappa B (proteasome inhibitors) and immunotherapy are described.

Characterization of a highly complex region in Xq13 and mapping of three isodicentric breakpoints associated with preleukemia

The chromosomal abnormality represented by an isodicentric X chromosome [idic(X)(q13)] is associated with a subset of acute myeloid leukemia (AML) and preleukemia observed in elderly females. A previous study localized the breakpoints of two acquired isodicentric X chromosomes associated with myelodysplasia to a 450-kb region proximal to the XIST gene. Here we report the construction and extensive characterization of a reliable 1-Mb P1 artificial chromosome and bacterial artificial chromosome contig covering a highly problematic region in Xq13 that includes the previously described isodicentric breakpoint region. In addition to mapping of the brain-specific gene (NAP1L2) and the phosphoglyceryl kinase alpha subunit 1 gene (PHKA1) and generation and mapping of a large number of STSs throughout the contig, we have mapped a putative transcriptional regulatory protein (HDACL1), and 35 ESTs. Sequencing data, Southern blot analysis, and fiber-FISH analysis have permitted characterization of extensive region-specific duplications and triplications in addition to an unusually high concentration of long interspersed repeat elements, both of which could be implicated in isodicentric chromosome formation and other Xq13 chromosome aberrations. FISH analysis of metaphase chromosomes from two previously unpublished AML patients and one preleukemic patient using cosmid clones and selected subclones allowed mapping of the idic(X)(q13) breakpoints to a 100-kb interval, consistent with the involvement of an X-linked gene in the genesis of this form of preleukemia, disruption of which may represent a preliminary step in progression to AML. Assembly and physical mapping of this complex 1-Mb contig establish a foundation for ongoing sequencing and gene identification projects in the region.

Chronic eosinophilic leukemia and hypereosinophilic syndromes. Proposal for classification, literature review, and report of a case with a unique chromosomal abnormality

The idiopathic hypereosinophilic syndromes (HES) are rare hematologic disorders characterized by persistent eosinophilia with organ involvement that encompass a wide spectrum of clinical and hematological disease states. We propose a classification scheme to further delineate these patients, and present a case of a 45-year-old male with persistent eosinophilia, severe tissue and hematologic involvement, and trisomy 15. Although multiple cytogenetic abnormalities have been associated with hypereosinophilic syndromes, this is the first reported case where trisomy 15 is the sole chromosomal abnormality.

Diagnosis of Ewing's sarcoma and peripheral neuroectodermal tumour based on the detection of t(11;22) using fluorescence in situ hybridisation

Fluorescence in situ hybridisation (FISH) has been used increasingly for gene mapping and ordering probes on interphase and metaphase preparations. The association of consistent chromosomal aberrations with certain malignancies allows the possibility of using interphase cytogenetics as a diagnostic tool. In small round cell tumours of children accurate diagnosis may be difficult using existing methods. We have therefore evaluated the diagnostic potential of this technique when applied to the characteristic t(11;22) found in Ewing's sarcoma and peripheral neuroectodermal tumour (ES and PNET). Interphase nuclei were prepared from normal human foreskin fibroblasts (HFF), two Ewing's sarcoma cell lines and several fresh tumour biopsies. DNA probes each side of the breakpoint at 22q12 were labelled with biotin and digoxygenin, hybridised to chromosomes in interphase and detected in different colours. Measurements between pairs of signals arising from each copy of chromosome 22 were taken and statistical analysis performed. There was a highly significant difference (P < 0.0001) between the two populations of measurements obtained (from nuclei with and without the t(11;22)). Studying four tumours and one further ES line (blind) it was found that median values from 30 nuclei could correctly identify which samples contained the t(11;22). This application of interphase cytogenetics contributes a reliable, accurate and conceptually simple diagnostic test for ES and PNET. It may now be applied to other tumours with characteristic translocations, amplifications or deletions when suitable probes are available. This approach is likely to become a routine in clinical diagnosis.

Pseudomosaicism, true mosaicism, and maternal cell contamination in amniotic fluid processed with in situ culture and robotic harvesting

This study was designed to test the usefulness of the common definitions for maternal cell contamination, true mosaicism, and pseudomosaicism for amniotic fluid specimens processed by in situ culture and robotic harvesting. We prospectively studied 4309 consecutive amniotic fluid specimens processed with these methods and found that 0.84 per cent had maternal cell contamination, 0.28 per cent had true mosaicism, and 5.4 per cent had pseudomosaicism. Although the frequencies of maternal cell contamination and true mosaicism were comparable to those in similar published studies, the frequency of pseudomosaicism was more than twice as high as that in previous reports. This finding is most likely not due to the method, but rather to a more accurate estimate of the actual frequency of pseudomosaicism in amniotic fluid cultures than reported heretofore. Follow-up clinical information was available on 72 per cent of the cases. In three cases of true mosaicism involving structural anomalies, the results of cytogenetic follow-up studies on the neonates were normal. None of the pseudomosaic cases involving trisomy 8, 13, 18, or 21; triple X; or monosomy X were associated with newborns who had birth defects.

Chromosome studies in 104 patients with polycythemia vera

Chromosome studies were done in 104 patients with various stages of polycythemia vera (PV): 10 had leukemia-myelodysplastic syndrome, 28 had post-PV with myeloid metaplasia (PPVMM), 12 had PV with myelofibrosis, and 54 had PV. Chromosome studies were successful in 86 patients, 37 (43%) of whom had a chromosome abnormality. At diagnosis, 4 of 28 patients (14%) had an abnormal clone; the incidence was 78% in PPVMM and 100% in leukemia-myelodysplastic syndrome. Among the 63 patients with successful chromosome studies during the first 10 years of disease, 27% had an abnormal clone. In contrast, of the 23 patients who had the disease for more than 10 years, 87% had an abnormal clone. Chromosome abnormalities were found in 11 of the 60 patients who either were untreated or underwent only phlebotomy and in 26 of the 44 patients who were treated with myelosuppressive agents. Trisomy 8, +9, and 20q- were found in some patients early during the course of their disease and also among untreated patients. These chromosome abnormalities seem to be related to the natural course of PV rather than to therapy. Patients with a chromosomally abnormal clone at the time of diagnosis of PV had a poorer survival than did those with only normal metaphases. Cytogenetic results did not predict evolution of the disease, but they did provide clues to hematologic phenotype, duration of the disease, and consequences of myelosuppressive therapy.

Breast cancer cytogenetics and beyond

It is hypothesized that cancers arise as a result of genetic or chromosomal alteration. Evidence for this is provided by the leukaemias and lymphomas in which cytogenetic studies are of established value in diagnosis, classification and follow-up. In contrast, the cytogenetic study of all solid tumours, including breast carcinoma, is in its infancy. However, cytogenetic studies indicate that clonal structural alterations do occur, affecting several loci on a number of chromosomes. Molecular studies provide further evidence of recurring chromosomal breakpoints in breast cancer. This paper reviews the chromosomal rearrangements observed to date and discusses their relevance to the biology of breast cancer.

Cold agglutination

Autoantibodies against red cells optimally reacting at 0 degree C, ie, CA, are normally found with low titers in the serum of human adults. High-titer CA may be induced by certain infectious agents, including M pneumoniae, EBV, CMV, and rubella virus, or may develop on the basis of chronic (malignant) B cell lymphoproliferation. The main clinical manifestation of cold agglutination is AIHA. Antigens and antibodies of cold agglutination are the best characterized reaction partners of a human autoimmune process. CA may recognize I and i antigens, which are lipid- and protein-linked branched and linear N-acetyl-lactosamine chains, respectively. They are precursors of the ABH blood group antigens and are converted into H by fucosylation. An alternative substitution by sialylation creates Gd, Fl, and probably Vo/Li antigens. CA with anti-Pr and anti-Sa specificities recognize 0-glycans with immunodominant sialyl groups on glycophorins. Several Pr subspecificities can be identified by chemically modified sialyl groups on glycophorins. Because CA in chronic lymphoproliferation are monoclonal antibodies, structure-specificity-interrelations of the antibodies could be identified by primary structure analyses of the N-terminal variable regions of H and L chains and by studies on CA idiotypes. Interrelations between distinct CA specificities and particular infectious agents could explain cold agglutination as a response to receptors for the agents or to the binding sites of antibodies against the agents. Interrelations also existing between certain CA isotypes (Ig classes and L chain types) and CA specificities could be a basis for the elucidation of the enigmatic etiology of chronic (malignant) monoclonal cold agglutination.

Significance of systemic mast cell disease with associated hematologic disorders

A clinical and hematopathologic review of 66 patients with systemic mast cell disease (SMCD) was undertaken to investigate the frequency and the clinical significance of associated hematologic disorders. Twenty-two patients were found to have a second hematologic disorder, 19 of which involved the myeloid cells (ten dysmyelopoietic syndromes, five myeloproliferative disorders, three acute nonlymphocytic leukemias, and one chronic neutropenia), and three of which involved the lymphoid cells (three malignant lymphomas). A chromosome analysis of the bone marrow revealed abnormalities characteristic of neoplastic myeloid disorders in four patients. Five-year survival for patients with hematologic disorders was 28% compared with 61% for other SMCD patients (P = 0.004). Patients with hematologic disorders differed significantly from other SMCD patients in that they were about 7 years older (P = 0.039), and they presented more commonly with anemia (P less than 0.001) and constitutional symptoms (P = 0.007). These patients also had less frequent skin symptoms (P = 0.003) and urticaria pigmentosa (P = 0.018). By definition, patients with hematologic disorders had a greater percent of hematopoiesis (P less than 0.001) and decreased fat cells (P = 0.011) on bone marrow biopsies. A multivariate model demonstrated that the following independent variables were associated with the presence of hematologic disorders: low hemoglobin (P = 0.001), the absence of hepatomegaly (P = 0.016), high leukocyte count (P = 0.021), and the presence of pathologic fractures (P = 0.051). The frequent coexistence of SMCD with dysplastic and neoplastic disorders of myeloid cells is consistent with the concept that SMCD itself is a disorder of myeloid cells and that the mast cell may be myeloid in origin.

Chromosomally abnormal clones and nonrandom telomeric translocations in cardiac myxomas

Cardiac myxomas from eight patients were examined cytogenetically in short-term cultures. Cultures could not be established in two of the eight cases. Chromosomally abnormal clones occurred in two of the myxomas; their karyotypes were 45,X,-Y,+7,-18 and 45,X,-Y. In three other myxomas, we found a rare kind of telomere-to-telomere translocation between chromosomes. The telomeres predominantly involved in these three tumors were the 2qter (the end of the long arm of chromosome 2), the 12pter (the end of the short arm of chromosome 12), and Yqter (the end of the long arm of the Y chromosome), respectively. In one other myxoma, 20% of the cells were tetraploid. These findings support the concept that myxomas are neoplastic; those with an abnormal clone may even have malignant potential. The unusual telomere-to-telomere translocations were not observed in a clonal pattern. They may represent a specific type of chromosomal instability associated with a defect in repair or replication of telomeric DNA.

Acute lymphocytic leukemia: correlation of clinical features with immunocytochemical classification

Many immunologic studies of acute lymphocytic leukemia (ALL) during the past decade have demonstrated the close correlation of immunologic phenotypes of ALL subclasses with the clinical presenting features and prognosis. However, the clinical application of conventional immunologic techniques had been very limited because of the requirement of a fresh sample to prepare the mononuclear cell suspensions for study. We studied 81 cases of ALL using immunoperoxidase stain for nuclear terminal deoxynucleotidyl transferase (TdT) and immunoalkaline phosphatase stain for surface markers (using monoclonal antibody J5 for common ALL antigen [CALLA], Leu-1 for pan-T antigen, and B1 for pan-B antigen) on air-dried smears. The cases were classified as common ALL (TdT+, CALLA+, pan-T-, and pan-B-) (41 cases), null-ALL (TdT+, CALLA-, pan-T-, and pan-B-) (19 cases), T-ALL (TdT+, CALLA-, pan-T+, and pan-B-) (nine cases), B-ALL (TdT-, CALLA-, pan-T-, and pan-B+) (six cases), pre-B-ALL (TdT+/-, CALLA+, pan-T-, and pan-B+) (four cases), or pre-T-ALL (TdT+, CALLA+, pan-T+, and pan-B-) (two cases). This subtyping of ALL correlated well with known clinical presenting features, prognosis, chromosome analysis in 35 cases with an abnormal clone, and conventional immunologic typing in 38 cases. The data suggest that these simple and practical immunocytochemical stains can be used for immunologic subclassification of ALL.

Granulocytic sarcoma in nonleukemic patients

Sixteen patients presenting with granulocytic sarcoma without evidence of acute leukemia were seen and diagnosed at The University of Texas M.D. Anderson Hospital and Tumor Institute at Houston from 1962 to 1985. Seven of them (44%) did not develop acute leukemia. Of these seven, four are alive with no evidence of disease 3.5 to 16 years after initial presentation; the remaining three patients died of their disease within 2 to 8 months of presentation. Two of 16 patients were diagnosed within the last 15 months and do not have adequate follow-up. The seven remaining patients developed acute leukemia within 1 week to 13 months of the diagnosis of granulocytic sarcoma. Six of them died 5 weeks to 16 months after diagnosis; one patient has been in complete remission for 8 years. Twelve of these 16 cases (75%) were initially misdiagnosed, most frequently as large cell lymphoma. The remaining four cases were correctly diagnosed as granulocytic sarcoma. The naphthol-ASD-chloroacetate esterase stain was required to make the correct diagnosis in all cases. Contrary to findings in other series, granulocytic sarcoma arising in nonleukemic patients does not necessarily progress to acute leukemia. At least four of 16 (25%) patients in this series did not develop acute leukemia during the 3.5 to 16 years they have been followed. No prognostic factors were identified in this series to predict which patients would develop acute leukemia and which ones would not.