AML, ALL, and CML classification and diagnosis based on bone marrow cell morphology combined with convolutional neural network: A STARD compliant diagnosis research

Leukemia diagnosis based on bone marrow cell morphology primarily relies on the manual microscopy of bone marrow smears. However, this method is greatly affected by subjective factors and tends to lead to misdiagnosis. This study proposes using bone marrow cell microscopy images and employs convolutional neural network (CNN) combined with transfer learning to establish an objective, rapid, and accurate method for classification and diagnosis of LKA (AML, ALL, and CML). We collected cell microscopy images of 104 bone marrow smears (including 18 healthy subjects, 53 AML patients, 23 ALL patients, and 18 CML patients). The perfect reflection algorithm and a self-adaptive filter algorithm were first used for preprocessing of bone marrow cell images collected from experiments. Subsequently, 3 CNN frameworks (Inception-V3, ResNet50, and DenseNet121) were used to construct classification models for the raw dataset and preprocessed dataset. Transfer learning was used to improve the prediction accuracy of the model. Results showed that the DenseNet121 model based on the preprocessed dataset provided the best classification results, with a prediction accuracy of 74.8%. The prediction accuracy of the DenseNet121 model that was obtained by transfer learning optimization was 95.3%, which was increased by 20.5%. In this model, the prediction accuracies of the normal groups, AML, ALL, and CML were 90%, 99%, 97%, and 95%, respectively. The results showed that the leukemic cell morphology classification and diagnosis based on CNN combined with transfer learning is feasible. Compared with conventional manual microscopy, this method is more rapid, accurate, and objective.

Chronic myelomonocytic leukemia: myelodysplastic or myeloproliferative?

Chronic myelomonocytic leukemia (CMML) is a clonal disease of the hematopoietic stem cell that provokes a stable increase in peripheral blood monocyte count. The World Health Organisation classification appropriately underlines that the disease combines dysplastic and proliferative features. The percentage of blast cells in the blood and bone marrow distinguishes CMML-1 from CMML-2. The disease is usually diagnosed after the age of 50, with a strong male predominance. Inconstant and non-specific cytogenetic aberrations have a negative prognostic impact. Recurrent gene mutations affect mainly the TET2, SRSF2, and ASXL1 genes. Median survival is 3 years, with patients dying from progression to AML (20-30%) or from cytopenias. ASXL1 is the only gene whose mutation predicts outcome and can be included within a prognostic score. Allogeneic stem cell transplantation is possibly curative but rarely feasible. Hydroxyurea, which is the conventional cytoreductive agent, is used in myeloproliferative forms, and demethylating agents could be efficient in the most aggressive forms of the disease.

Blast count and cytogenetics correlate and are useful parameters for the evaluation of different phases in chronic myeloid leukemia

Staging of chronic myeloid leukemia (CML) phases is based on cytomorphological criteria that vary considerably between different staging systems. Thus, staging of CML is heterogeneous and causes problems with respect to the comparison of therapeutical strategies and clinical outcome. We evaluated 59 patients with CML in different stages of the disease. In order to define which cytomorphological parameters correlate with cytogenetics we investigated cytomorphology and cytogenetics in parallel in all cases. As a result, bone marrow blast count demonstrated a highly significant correlation with the respective cytogenetic results of the patients and was clearly linked to the frequency and complexity of clonal evolution. We therefore propose to focus staging systems of CML on the correlation of the percentage of bone marrow blasts and the cytogenetic results.

Prognostic significance of the histomorphometric features of bone marrow trephine biopsies in patients with chronic myeloid leukemia

OBJECTIVE

To study the correlation of histomorphometric data of bone marrow trephine biopsies at the time of initial diagnosis in chronic myeloid leukemia (CML) patients with the patient prognosis.

STUDY DESIGN

A total of 40 CML patients were divided equally in group I (developed accelerated phase or blast crisis within 18 months of initial diagnosis of chronic phase of CML) and group II (developed accelerated phase or blast crisis > 30 months after initial diagnosis of chronic phase of CML). The clinical, hematologic and histomorphometric data were compared in the 2 groups of CML patients.

RESULTS

The percentage of bone marrow promyelocytes was significantly increased in group I. On morphometry, the number of blasts per square millimeter, the area of reticulin fibers per square millimeter and the percentage area occupied by reticulin fibers were statistically significant.

CONCLUSION

There seems to be grounds for hope for predicting prognosis of CML patients at initial diagnosis based on histomorphometric findings. The percentage area of reticulin fibers and the number of blasts per square millimeter are important prognostic predictors in histomorphometry data.

Chronic myeloproliferative disorders: the role of tyrosine kinases in pathogenesis, diagnosis and therapy

The term chronic myeloproliferative disorders was originally used by Damashek to describe the link amongst a group of acquired blood diseases. Recent molecular genetic analysis has provided a scientific basis for this observation. Underlying myeloproliferative disorders are acquired abnormalities of tyrosine kinase genes. These may be chromosomal translocations resulting in the creation of a fusion kinase gene, examples of which include ABL, FGFR, and PDGFR as seen in disorders CML, 8p11 myeloproliferative syndrome, atypical CML and chronic eosinophilic leukaemia. The second group of tyrosine kinase abnormalities are point mutations in JAK2, a cytosolic TK. This abnormality is seen in 30-97% of cases of MPD with the phenotype PV, ET or CIMF.

Myelofibrosis – What’s in a Name?

OBJECTIVE

Myelofibrosis (MF) implies an increase in the bone marrow (BM) fiber content without referring to quantity or quality (reticulin vs. collagen).

METHODS

This review on chronic myeloproliferative disorders is based on initial and sequential BM biopsies, clinical data and follow-up examinations. A semiquantitative grading system for MF approved by a panel of experts was applied.

RESULTS

In chronic myelogenous leukemia, minimal reticulin to advanced collagen MF is detectable at presentation in about 30% of patients. Significant correlations between BM and clinical features, but especially prognosis, are evident. Chronic idiopathic MF includes a prodromal stage showing no or little reticulin and no relevant MF with myeloid metaplasia (MMM). A stepwise evolution is demonstrable and associated with corresponding clinical data. Usually MMM is the diagnostic guideline for this disorder and consequently early stages with accompanying thrombocytosis may clinically mimic essential thrombocythemia. MF of various degrees may be observed in polycythemia vera depending on the progress of disease. Terminal stages (spent phase) reveal overt collagen corresponding with MMM. If diagnosis of essential thrombocythemia regards characteristic BM features, no relevant MF is seen at presentation and transformation into MMM is neglectable for many years.

CONCLUSION

To recognize dynamics of the disease process in chronic myeloproliferative disorders, an easily to reproduce scoring system for MF has been proposed. The clinical diagnosis of MMM does not include initial-early reticulin MF and therefore fails to detect prodromal stages.

Myelodysplastic and myeloproliferative disorders in children

PURPOSE OF REVIEW

Myelodysplastic and myeloproliferative disorders are clonal myeloid malignancies characterized by the triad of a growth advantage of clonal cells, disturbed differentiation and increased apoptosis. The rarity of these disorders in children and the lack of a widely accepted classification have contributed to the paucity of reports on these malignancies in the pediatric literature. A number of significant advances have been achieved in recent years. The present review will focus on diagnostics and therapy.

RECENT FINDINGS

International consensus has been achieved on classifying these disorders into three main groups; myelodysplastic syndrome (MDS), myeloid leukemia of Down syndrome (ML-DS) and juvenile myelomonocytic leukemia (JMML). In the last few years we have witnessed important advances, especially regarding the therapy of these disorders, and we have gained insights into the molecular pathogenesis of ML-DS and JMML.

SUMMARY

Classification of myelodysplastic and myeloproliferative disorders has been facilitated. Chemotherapy regimens for ML-DS have been reduced, resulting in fewer toxic deaths and improved survival. The results of stem-cell transplantation for MDS and JMML have improved. Insight into the molecular mechanisms involved may open new therapeutic avenues.

The Biology of Chronic Myelogenous Leukemia: Implications for Imatinib Therapy

Chronic myelogenous leukemia (CML) results from the neoplastic transformation of primitive hematopoietic stem cells, and has been classified as a myeloproliferative disorder. The hallmark of CML is the presence of a balanced translocation between the long arms of chromosomes 9 and 22, t(9;22)(q34;q11.2), which is known as the Philadelphia (Ph) chromosome. This translocation results in the formation of the bcr-abl fusion gene, which, in turn, is translated into a chimeric Bcr-Abl protein with deregulated tyrosine kinase activity. Constitutive Bcr-Abl expression has been shown to be necessary and sufficient for the transformed phenotype of CML cells. CML is unique among human cancers in that a single genetic defect, the Ph chromosome, is responsible for the transformed phenotype. Since this discovery more than 40 years ago, our understanding of the clinical course, therapy, and prognosis of patients with CML has changed significantly. These changes have culminated in the emergence of imatinib, the first rationally designed, molecularly targeted therapy for human malignancy. In this review, the authors describe the molecular biology of CML and the development of imatinib as a therapeutic agent for the treatment of CML.

Classification of chronic myeloid disorders: From Dameshek towards a semi-molecular system

Hematological malignancies are phenotypically organized into lymphoid and myeloid disorders, although such a distinction might not be precise from the standpoint of lineage clonality. In turn, myeloid malignancies are broadly categorized into either acute myeloid leukemia (AML) or chronic myeloid disorder (CMD), depending on the presence or absence, respectively, of AML-defining cytomorphologic and cytogenetic features. The CMD are traditionally classified by their morphologic appearances into discrete clinicopathologic entities based primarily on subjective technologies. It has now become evident that most CMD represent clonal stem cell processes where the primary oncogenic event has been characterized in certain instances; Bcr/Abl in chronic myeloid leukemia, FIP1L1-PDGFRA or c-kit(D816V) in systemic mastocytosis, rearrangements of PDGFRB in chronic eosinophilic leukemia, and rearrangements of FGFR1 in stem cell leukemia/lymphoma syndrome. In addition, Bcr/Abl-negative classic myeloproliferative disorders are characterized by recurrent JAK2(V617F) mutations, whereas other mutations affecting the RAS signaling pathway molecules have been associated with juvenile myelomonocytic leukemia. Such progress is paving the way for a transition from a histologic to a semi-molecular classification system that preserves conventional terminology, while incorporating new information on molecular pathogenesis.

Systemic mastocytosis (SM) associated with chronic eosinophilic leukemia (SM-CEL): Detection of FIP1L1/PDGFRα, classification by WHO criteria, and response to therapy with imatinib

Based on generally accepted criteria and the WHO-classification, a subset of patients with systemic mastocytosis (SM) have (or develop) an associated clonal hematologic non-mast cell lineage disease (SM-AHNMD). We describe a case of SM with coexisting chronic eosinophilic leukemia (SM-CEL). The patient, a 51-year-old male, was first seen in 1992 with small-sized infiltrates of spindle-shaped mast cells in his marrow, and marked eosinophilia. Retrospectively, a CHIC2 deletion and the FIP1L1/PDGFRalpha fusion gene-product were demonstrable by FISH analysis and RT-PCR, respectively. SM-associated organopathy or mediator-related symptoms were not recorded. However, the patient developed cardiomyopathy. Therapy with interferon-alpha, hydroxyurea, and corticosteroids were without effects. By contrast, therapy with imatinib was followed by a fast and sustained response with complete and stable regression of eosinophilia, drop in eosinophil cationic protein, and decrease of serum tryptase to normal levels. This case provides further evidence for the potential of co-existence of SM with a primary eosinophilic disorder (CEL) defined by the FIP1L1/PDGFRalpha fusion gene. Because of the availability of a superior targeted drug (imatinib), it is of importance to screen for FIP1L1/PDGFRalpha in suspected CEL with or without co-existing SM.

A critical reappraisal of the WHO classification of the chronic myeloproliferative disorders

Following the introduction of the WHO classification of chronic myeloproliferative disorders (MPDs), after approximately 5 years, a critical reappraisal appears to be warranted. Retrospective clinico-pathological evaluations conducted in the meantime, as well as the detection of new biomarkers, may aid in testing the validity of these new criteria. Based on a large series of patients with chronic myeloid leukemia (CML), an analysis of bone marrow (BM) features and risk classifications revealed that the fiber content exerted a most important and independent impact on prognosis. This finding was also supported in a prospective randomized study and therefore myelofibrosis should be included in any staging system in CML related to survival. Moreover, it is important to emphasize the dynamics of the disease process in MPDs, especially in polycythemia vera (PV) and chronic idiopathic myelofibrosis (CIMF). Latent-stage PV is difficult to recognize when adhering to the proposed limits for hemoglobin (or red cell mass) without regarding the erythropoietin (EPO) level, endogenous erythroid colonies (EECs) or BM histopathology. Initial PV may firstly present with complications and, when accompanied by a high platelet count, mimics essential thrombocythemia (ET). Consequently, BM morphology and EPO level should be entered as major diagnostic criteria for PV. To document more accurately the progress of disease, a simplified scoring system concerning myelofibrosis has to be included in the histological description of CIMF. The diagnostic guidelines of BM features in ET should be improved because, usually, there is neither a significant proliferation nor left-shifting of the granulo- and erythropoiesis detectable and no relevant increase in reticulin. A comparison of clinical data and BM morphology reveals that biomarkers (EPO, EECs, PRV-1, JAK2) show an overlapping pattern of positivity between the different subtypes of MPDs.

Diagnostic role of conventional cytogenetics and fluorescence in situ hybridization (FISH) in chronic myeloid leukemia patients

INTRODUCTION

The limitation of cytogenetic analysis is that the Ph chromosome cannot be detected in clumped metaphase or in interphase cells. Fluorescence in situ hybridization (FISH) is a highly sensitive molecular genetic technique, which enables to detect break point cluster region--Abelson (BCR-ABL) complex and minimal residual disease in all Ph positive CML patients not only in metaphase but also in interphase cells.

AIMS

To detect Ph chromosome in CML patients by the use of conventional cytogenetics and FISH.

MATERIAL AND METHODS

The bone marrow samples were collected in heparinised syringe from 35 diagnosed CML patients and transported to cytogenetic laboratory for chromosomal analysis. Conventional karyotype was prepared by direct harvesting and short-term culture. The FISH analysis was carried out on interphase cells of two patients to confirm the cytogenetic diagnosis.

RESULTS

Out of 35 CML patients, 17 (49.9%) were 100% Philadelphia positive, 10(28.5%) were 50-70% Ph+ mosaics and 3(9%) were 100% Ph negative. In 5 patients (14.25%) cytogenetic analysis failed to confirm the presence or absence of Ph chromosome. FISH was carried out in interphase cells from bone marrow preparations of two patients. The signals for BCR-ABL fusion gene was absent in Ph- negative CML patients. In Ph positive patients, the FISH analysis detected BCR-ABL fusion gene seen as a yellow signal on interphase cells.

CONCLUSION

Conventional cytogenetics is a useful method for detection of Ph chromosome in metaphase stage of cell division. FISH can be used in interphase stage of cell division for the same purpose.

Staging of chronic myeloid leukemia in the imatinib era

BACKGROUND

Several staging classification systems, all of which were designed in the preimatinib era, are used for chronic myeloid leukemia (CML). The World Health Organization (WHO) recently proposed a new classification system that has not been validated clinically. The authors investigated the significance of the WHO classification system and compared it with the classification systems used to date in imatinib trials ("standard definition") to determine its impact in establishing the outcome of patients after therapy with imatinib.

METHODS

In total, 809 patients who received imatinib for CML were classified into chronic phase (CP), accelerated phase (AP), and blast phase (BP) based on standard definitions and then were reclassified according to the new WHO classification system. Their outcomes with imatinib therapy were compared, and the value of individual components of these classification systems was determined.

RESULTS

With the WHO classification, 78 patients (10%) were reclassified: 45 patients (6%) were reclassified from CP to AP, 14 patients (2%) were reclassified from AP to CP, and 19 patients (2%) were reclassified from AP to BP. The rates of complete cytogenetic response for patients in CP, AP, and BP according to the standard definition were 72%, 45%, and 8%, respectively. After these patients were reclassified according to WHO criteria, the response rates were 77% (P = 0.07), 39% (P = 0.28), and 11% (P = 0.61), respectively. The 3-year survival rates were 91%, 65%, and 10%, respectively, according to the standard classification and 95% (P = 0.05), 63% (P = 0.76), and 16% (P = 0.18), respectively, according to the WHO classification. Patients who had a blast percentage of 20-29%, which is considered CML-BP according to the WHO classification, had a significantly better response rate (21% vs. 8%; P = 0.11) and 3-year survival rate (42% vs. 10%; P = 0.0001) compared with patients who had blasts > or = 30%.

CONCLUSIONS

Different classification systems had an impact on the outcome of patients, and some prognostic features had different prognostic implications in the imatinib era. The authors believe that a new, uniform staging system for CML is warranted, and they propose such a system.

Outcome of hematopoietic stem cell transplantation in patients with atypical chronic myeloid leukemia

Atypical chronic myeloid leukemia (aCML) occurs rarely and is associated with a poor prognosis when treated with conventional chemotherapy. We evaluated the outcome of aCML after allogeneic hematopoietic stem cell transplantation (HSCT). Nine patients were transplanted from HLA-identical siblings (n = 4), HLA-compatible unrelated donors (n = 4) or twin brother (n = 1). Median follow-up was 55 months after transplant (range, 9.1-118.1 months). One patient who was transplanted in advanced disease with bone marrow from his twin brother relapsed 19 months post transplant. This patient was successfully retransplanted from the original donor. All patients remained in complete remission. Analysis of the leukocyte chimerism of peripheral white blood cells and bone marrow buffy coat cells by VNTR-polymerase chain reaction (PCR) and single-nucleotide polymorphism real-time PCR revealed complete chimerism in all patients who had received an allogeneic transplant. One patient suffering from cerebral toxoplasmosis died 9 months post transplant. All other patients were alive at the time of analysis. Our findings suggest that the outcome of allogeneic or syngeneic transplantation in patients with aCML may not be worse than the outcome of transplantation for BCR-ABL-positive CML.

Expression of IFITM1 in chronic myeloid leukemia patients

We investigated the peripheral blood gene expression profile of interferon induced transmembrane protein 1 (IFITM1) in sixty chronic myeloid leukemia (CML) patients classified according to new prognostic score (NPS). IFITM1 is a component of a multimeric complex involved in the trunsduction of antiproliferative and cell adhesion signals. Expression level of IFITM1 was found significantly different between the high- and low-risk groups (P = 9.7976 x 10(-11)) by real-time reverse transcription polymerase chain reaction (RT-PCR). Higher IFITM1 expression correlated with improved survival (P = 0.01). These results indicate that IFITM1 expression profiling could be used for molecular classification of CML, which may also predict survival.

[Immunophenotyping of peripheral blood leukemic cells by multi-parameter cytometry]

AIM

To explore the clinical application and significance of CD45/SCC gating strategy of multi-parameter cytometry and tricolor fluorescence-labeled monoclonal antibodies in immunophenotyping of peripheral blood leukocytes in leukemia.

METHODS

Peripheral blood leukocytes were stained with CD45 combined with a panel of monoclonal antibodies to different lineage markers. CD45/SSC dot plot was formed and leukemic cell colony, once displayed, was gated for immunophenotyping.

RESULTS

144 patients with acute leukemia and 51 with chronic leukemia were enrolled. Distinguishable leukemic cell colony was found in 137 out of 144 specimens. 66 patients were immunologically classified as ALL and 67 as AML. 4 patients were unable to be classified immunophenotypically. 27 AL patients coexpressed markers of another cell lineage (20%). Immunophenotypic features of different types of leukemia were described. It is a common phenomenon that AL of one lineage coexpressed markers of another lineage.

CONCLUSION

An accurate immunophenotyping of leukemia can be realised when leukemic cell colony is displayed and analyzed by CD45/SCC pattern and gating strategy, which is important for clinical treatment and prognosis judgment.

Chronic myeloid leukaemia in central Africans

OBJECTIVES

To document the pattern of presenting clinical and haematological features of chronic myeloid leukaemia (CML) in central Africans and evaluate the clinical consequences of treating the disease with chemotherapy.

DESIGN

Prospective descriptive analysis of clinical and haematological data.

SETTING

Departments of Haematology of tertiary referral centres and teaching hospitals.

MATERIALS AND METHODS

Prospective clinical and haematological data were collected on 150 central Africans (90 Zimbabweans and 60 Malawians) using modern Coulter counters and standard up-to-date haematological procedures and the results analysed using predetermined criteria and the top-desk Scientific Calculator Model HP 48GX, Texas Instruments, USA.

RESULTS

There were 150 CML patients studied. Males predominated in a ratio of 1:5:1. The youngest patient was 10 years and the oldest 77 years with a mean +/- s.d. of 38.9 +/- 14.7 years. The peak age incidence of 47.3% occurred between 21 to 40 years. The Ph chromosome was found in 19 of the 20 patients studied. Although complaints attributed to splenic enlargement were the most common symptoms, several unusual clinical features were encountered viz: hepatomegaly (26%), bleeding (12%), significant lymphadenopathy (11.3%), purpura (3.3%), skin infiltration (2.7%), cardiac failure (2.7%) and 14.7% were diagnosed incidentally. Symptoms such as fatigue, headaches and weight loss were associated with greater degrees of leucocytosis, severe to gross splenomegaly and lower haemoglobin levels. The severe to gross splenomegaly which occurred in 68(45.3%) suggests that patients in this part of the world seek medical advice rather late in the disease. The median survival times of 65,47 and 39 months respectively for alpha interferon, hydroxyurea and busulphan are in agreement with those of previous larger series from other parts of the world.

CONCLUSIONS

The study has revealed that the presenting pattern of clinical and haematological features of CML is changing probably due to the advent of modern clinical practice coupled with increased physician density, greater awareness of disease among clinicians besides other reasons. However, optimal treatment is not possible for the majority of patients due to lack of chemotherapeutic agents and supportive care.

RECOMMENDATION

Referral centres in African health systems should be equipped for better management of CML patients.

[Chronic myeloid leukemia in 2003]

The recent introduction of imatinib mesylate has deeply changed the treatment of chronic myeloid leukemia. This first physiopathology-based therapy, which targets the molecular anomaly that gives rise to the disease (the abnormal tyrosine kinase activity generated by the fusion protein P210 Bcr-Abl) has demonstrated an impressive activity. However, its long-term efficacy remains unknown. On the other hand, other treatment modalities, such as stem cell transplantation or experimental ones (immunotherapy) are also profoundly evolving. In this review, the authors have tried to synthesize the current knowledge of this disease and suggest a therapeutic strategy based on the currently available data.

Utility of a prognostic scoring system for allogeneic stem cell transplantation in patients with chronic myeloid leukemia

Allogeneic stem cell transplantation (SCT) is the treatment of choice for selected patients with chronic myeloid leukemia (CML). However, it is associated with a high risk of treatment-related mortality (TRM) and morbidity. To assist in decision making about transplantation, a simple scoring system to assess the risk is needed. We analyzed the utility of a scoring system, first reported by the European Group for Blood and Marrow Transplantation (EBMT). We analyzed the data from 31 patients who underwent allogeneic transplantation at our institution, using the EBMT scoring system. It was based on five pretransplant risk factors: donor type, stage of disease at time of transplantation, age of recipient, sex of donor and recipient, and interval between diagnosis and transplant. Seventeen patients had a risk score of 0-2, and 14 patients had a score of 3-7. Using Kaplan-Meier analysis, the estimated 4-year leukemia-free (LFS) and overall survival (OS) for patients with a score of 0-2 were 47 and 53%, respectively. In contrast, the estimated 4-year LFS and OS for patients with a score of 3-7 were 10.5 and 10.5%, respectively. Four-year TRM was 47% for the low-risk group (0-2), and 85% for the high-risk group (3- 7). This simple scoring system may play an important role in predicting the outcome of allogeneic SCT, and in choosing the appropriate therapy for patients with CML.

Chronic basophilic leukemia: a distinct clinico-pathologic entity?

OBJECTIVE

We sought to better define a group of rare and poorly understood myeloproliferative disorders that are characterized by prominent chronic basophilia in the absence of the Philadelphia chromosome (Ph) or its molecular equivalent.

METHODS

We screened our institution's electronic database from 1975 onwards, and identified four such cases. Clinical data and bone marrow pathology were carefully reviewed for these patients.

RESULTS

Two patients had prominent manifestations of basophil mediator-release and another presented with pituitary dysfunction. Bone marrow examination uniformly revealed trilineage hyperplasia with basophilia and eosinophilia, dysplastic megakaryocytic hyperplasia, and the absence of megakaryocyte clustering. An abnormal pattern of atypical mast cells was noted in two cases. While disease palliation was effectively achieved with hydroxyurea for one patient, transformation to acute myeloid leukemia was eventually observed in this case. Another patient has achieved long-term disease-free survival after undergoing allogeneic stem cell transplantation.

CONCLUSIONS

Our observations reveal a striking pathologic similarity among all four cases, and suggest this disease, which may be aggressive with the potential to transform into acute leukemia, to possibly represent a distinct clinico-pathologic entity (chronic basophilic leukemia).

Advanced-phase chronic myeloid leukemia

Chronic myeloid leukemia (CML) typically runs a biphasic or triphasic course, with diagnoses usually made in the chronic phase (CP). Without effective treatment, patients eventually progress to a blastic phase (BP), frequently through an intermediate or accelerated phase (AP). Because the definition of AP varies among studies, comparisons of outcome and prognosis are difficult. The management of patients in these advanced phases of the disease has been much less satisfactory than that of patients in CP. Treatment with interferon-alfa (IFNalpha)-based therapy is ineffective for most patients in AP and for all of those in BP. Imatinib mesylate has demonstrated significant activity AP and BP disease, although the results are inferior compared to treatment in CP. In AP, 82% of patients achieve a hematologic response, with 24% achieving a major cytogenetic remission (MCR). Early MCR (within 3 months of diagnosis) provides a survival advantage over patients who do not achieve this response or achieve it later. In BP, 21% of previously treated patients and 36% of previously untreated patients have responded to imatinib, and up to 17% of patients may achieve a major cytogenetic response. However, responses are frequently short-lived. Several agents are being investigated for treatment of advanced-phase CML, including decitabine (DAC), homoharringtonine (HHT), troxacitabine, clofarabine, farnesyl transferase (FTase) inhibitors (FTI), and others. Many have also proven to be synergistic with imatinib in vitro and combination studies are ongoing. Continued investigation of these approaches is needed to improve the long-term prognosis of advanced-phase CML.

[The morphological, immunophenotypical and cytogenetic characteristics study of blast crisis in chronic myeloid leukemia]

OBJECTIVE

To explore the morphological, immunophenotypical and cytogenetic (MIC) characteristics of chronic myeloid leukemia in blast crisis (CML-BC).

METHODS

Marrow cells from 31 CML-BC patients were studied by bone marrow smears with morphological and cytochemical stain analysis. Immunophenotypic analysis was performed by micro blood method and flow cytometry. Cytogenetic analysis was performed using bone marrow cells prepared directly and or after 24 hours culture. RHG banding was used for karyotypic analysis.

RESULTS

23 patients (74.2%) were found to have myeloid blast crisis. 5 cases (16.1%) had a B-lymphoid immunophenotype and 4 of them expressed myeloid associated antigens at the same time. Another 3 cases were classified as acute undifferentiated leukemia (AUL 1 patient) and acute myeloid -lymphoid leukemia (AMLL 2 patients) with B and myeloid markers expression. A significant proportion (67.7%) of blast crisis cases were CD(34) positive. CD(34) was expressed in 80.0% of lymphoid and 65.2% of myeloid BC. Analysis of the relationship between CD(7) and CD(34) expression in blasts of myeloid crisis showed their dual expression in 8/23 (34.8%) of the cases. Cytogenetic analysis indicated that 14/27 (51.9%) of the patients had developed secondary cytogenetic abnormalities in addition to the Ph chromosome. These newly emerging abnormalities included a trisomy 8 in 3 patients, a double Ph chromosome in 3 patients, an iso chromosome 17q in 2 patients, loss of Y chromosome in 1 patent and other complicated translocation in 5 patients.

CONCLUSION

Blast crisis of CML is a kind of disease of stem cell. The differentiation of blast cell is blocked in the early stage. The prognosis of such patients is poor. MIC showed its important values in diagnosis, judgement of prognosis and determination of therapeutic protocol of CML-BC.

The use of imatinib (STI571) in chronic myelod leukemia: some practical considerations

BACKGROUND AND OBJECTIVES

The new Abl tyrosine kinase inhibitor imatinib (imatinib mesylate, STI571) is very effective in the treatment of patients with chronic myeloid leukemia (CML). It induces complete hematologic control in >90% of patients with CML in chronic phase and preliminary data suggest that the incidence of complete cytogenetic remission may exceed 60% in previously untreated patients, though its capacity to prolong life in comparison with other agents has not yet been clearly established. It is also active in the management of patients in advanced phases of CML.

INFORMATION SOURCES

We present here provisional indications for the use of imatinib in CML patients and give details of the dosage regimens we have used and side-effects we have encountered.

STATE OF THE ART AND PERSPECTIVES

It is likely that the optimal usage of this important new agent will become better defined as more experience is gained.

Spectral karyotyping refined the identification of a der(Y)t(Y;1)(q11.1 or.2;q12) in the blast cells of a patient with atypical chronic myeloid leukemia

We report a case of atypical chronic myeloid leukemia who showed leukocytosis with immature granulocytes and dysplastic features but no monocytosis or basophilia. Cytogenetic analysis by conventional G-banding showed an abnormal clone, which was interpreted as 46,X,-Y,+der(?)t(?;1)(?;q?1), and no Philadelphia chromosome. Reverse transcription-polymerase chain reaction did not show either major or minor BCR-ABL chimeric mRNA. Spectral karyotyping (SKY) and fluorescence in situ hybridization (FISH) refined the karyotype to 46,X,der(Y)t(Y;1)(q11.1 or.2;q12). The der(Y)t(Y;1) abnormality was reported previously in 9 cases and associated with myelodysplastic syndrome or chronic myeloproliferative disorders. SKY in combination with the standard banding method and FISH may be useful for exploring undefined chromosome abnormalities in hematological disorders.

Bone marrow trephine biopsy findings in chronic myeloid leukemia

Sixty patients with chronic myeloid leukemia (CML) underwent bone marrow trephine biopsy at presentation. All the biopsies were decalcified, paraffin-embedded and stained with H&E, Gomori's reticulin and Masson Trichrome. A detailed study of the histology including the morphology and topographic distribution of megakaryocytes was done. 55 patients presented in chronic phase. Of these there were 37 cases (67%) of CML-granulocytic (CML-G) type and 18 cases (33%) of CML-granulocytic megakaryocytic (CML -GM) type. Five cases presented in blast crisis. 73% of CML-G had low-grade fibrosis while 83% of CML-GM had high-grade fibrosis. This was statistically significant. On follow-up 25% of CML-G went into blast crisis while all the CML-GM patients remained stable to date. Bone marrow biopsy is a useful investigation in patients of CML at diagnosis as it provides prognostic information. Evaluation of megakaryopoiesis, grading of fibrosis and localization of blasts are possible on a trephine biopsy.

Microsatellite instability and cytogenetic survey in myeloid leukemias

Microsatellites are short tandem repeat sequences dispersed throughout the genome. Their instability at multiple genetic loci may result from mismatch repair errors and it occurs in hereditary nonpolyposis colorectal cancer. This instability is also found in many sporadic cancers. In order to evaluate the importance of this process in myeloid leukemias, we studied five loci in different chromosomes of 43 patients, 22 with chronic myelocytic leukemia (CML) in the chronic phase, 7 with CML in blast crisis, and 14 with acute myeloid leukemia (AML), by comparing leukemic DNA extracted from bone marrow and constitutional DNA obtained from buccal epithelial cells. Only one of the 43 patients (2.1%), with relapsed AML, showed an alteration in the allele length at a single locus. Cytogenetic analysis was performed in order to improve the characterization of leukemic subtypes and to determine if specific chromosome aberrations were associated with the presence of microsatellite instability. Several chromosome aberrations were observed, most of them detected at diagnosis and during follow-up of the patients, according to current literature. These findings suggest that microsatellite instability is an infrequent genetic event in myeloid leukemias, adding support to the current view that the mechanisms of genomic instability in solid tumors differ from those observed in leukemias, where specific chromosome aberrations seem to play a major role.

Management of the chronic leukemias: special considerations in the elderly patient. Part III rarer chronic myeloid leukemias

The manifestations, diagnosis and management of the rarer chronic myeloid leukemias are reviewed, with special attention to problems that affect elderly patients. The spectrum of disorders includes atypical myeloproliferative syndrome, so-called Ph-negative CGL, chronic myelomonocytic leukemia, and leukemias characterized by chronic proliferation of neutrophil, eosinophil, or basophil leukocytes. These latter are sometimes difficult to differentiate from chronic nonleukemic proliferations of the index cells. Termination in an acute myeloid leukaemia that is usually refractory to treatment may occur in any of the above disorders but is not a constant event.

[Clinical epidemiology]

Although the exact incidence of chronic myeloid leukemia(CML) in Japan is obscure, the occurrence rate of CML is approximately 15% of all leukemia patients in Japan, and thus about 5/100,000 cases appeared per year. This incidence of CML seems to be lower that that of Caucasian, but the incidence of CML patients in Japan may increase gradually. Molecular investigation in CML disclosed the exact mechanism of t(9; 22) anomaly, thus providing appropriate classification for chronic myeloid leukemia. From the etiological aspect, it is well documented that exposure to atomic bomb at Nagasaki and Hiroshima actually induced CML, however, factors other than irradiation are still obscure. Recent spread of annual examination pick up some CML patients at the early phase and the disease severity might be thus different from those of previous CML patients. For example, currently diagnosed CML patients usually lack palpable splenomegaly and some of them had normal karyotypes in addition to Ph-cells in the bone marrow at the time of CML diagnosis. These findings indicate that epidemiological aspect in CML patients might be changing.

[Chronic myeloproliferative disorders. The new WHO classification]

Except for chronic myelogenous leukemia (CML), chronic myeloproliferative disorders (CMPDs) include as main subtypes polycythemia vera (PV), chronic idiopathic myelofibrosis (IMF), and essential thrombocythemia (ET). A common finding in CMPDs is a clonal evolution associated with a significantly variable course, which may be complicated by thrombocythemia, (secondary) myelofibrosis, and finally acceleration (unstable phase) that merges into blastic crisis. New therapeutic modalities (chemo- and interferon therapy, bone marrow and stem cell transplantation) which were developed in the last decade and the striking differences in survival amongst the different subtypes warrant not only an unequivocal distinction from reactive and allied disorders, but a clear-cut classification as well. For this reason, a synoptical approach is essential including clinical data and, as a major diagnostic tool, a bone marrow biopsy. This concept finds expression in the new WHO classification, which also includes as rare subtypes chronic neutrophilic leukemia, eosinophilic leukemia, chronic hypereosinophilic syndrome, and finally unclassifiable entities. Histopathology of bone marrow biopsies reveals specific findings, in particular concerning megakaryopoiesis, which are characteristic for the different subtypes. These features facilitate the still controversially discussed differentiation of thrombocythemia that is frequently present, as is the case in initial (prefibrotic) IMF from ET. Moreover, in addition to clinical findings,the associated heterogeneity of bone marrow morphology indicates a stepwise evolution of the disease process and thus exerts a significant impact on survival, i.e., in CML regarding erythropoiesis and myelofibrosis and in IMF extent of myeloid metaplasia.

Clinical, hematological and cytogenetic characteristics of atypical chronic myeloid leukemia

BACKGROUND

Atypical chronic myeloid leukemia (aCML) is an infrequent chronic myeloproliferative disorder characterized by leukocytosis, absence of Philadelphia chromosome or BCR-ABL rearrangement, and marked myeloid dysplasia. Some cases have an absolute monocytosis but can be distinguished from chronic myelomonocytic leukemia (CMML) by the presence of a higher percentage (> 15%) of circulating immature granulocytes.

PATIENTS AND METHODS

In a series of 11 patients with a diagnosis of aCML according to the FAB proposals we have analyzed the most relevant clinical, hematological and cytogenetic characteristics.

RESULTS

The median age was 65 years (16-84). All but one case showed, at time of diagnosis, leukocytosis (median WBC was 36 x 10(9)/l), 55% had moderate anemia and 36% had thrombocytopenia. Most cases had marked dysplasia, particularly in the granulocytic lineage (82% of the cases), and all cases showed bone marrow red hypoplasia. Cytogenetic abnormalities were present in 9 out of the 11 patients. Trisomy 8 was observed in three cases and other clonal chromosomal abnormalities included deletions of 5q, 13q, 17p, 12q, and 11q as well as a t(6;8)(p23;q22) translocation. Fluorescence in situ hybridization (FISH) studies failed to demonstrate ETV-6 gene involvement. The median survival time from diagnosis was only 14 months (range 3-56 months).

CONCLUSIONS

These data suggest that aCML is a rare disease which is characterized by leukocytosis, with dysgranulopoiesis, BM erythroid hypoplasia, chromosomal, though not recurrent, abnormalities and poor prognosis.

[Atypical chronic myeloid leukemia presenting with trilineage dysplasia and IgG (lambda) type monoclonal gammopathy]

A 78-year-old man was diagnosed as leukocytosis in February 1994. Physical examination revealed marked hepatosplenomegaly. A peripheral blood examination disclosed 95,090/microliter leukocytes without hiatus leukemicus, 6.5 g/dl Hb, and 15.0 x 10(4)/microliter platelets. The neutrophil alkaline phosphatase score was 27, and serum VB12 was above 1,600pg/ml. IgG was identified as monoclonal immunoglobulin of type lambda. Bone marrow specimens demonstrated marked granulocytic hyperplasia. Neither the Philadelphia chromosome (Ph1) nor BCR gene rearrangement was detected; hence, the diagnosis of Ph1 (-) chronic myeloid leukemia (CML) was made. The patient was treated with hydroxyurea and low-dose VP-16 with no improvement, and died of pneumonia and sepsis in June 1995. This case was considered to be consistent with atypical CML (aCML) according to the FAB classification because monocytosis was not observed. It seems likely and interesting that the coexistent monoclonal gammopathy and aCML might have arisen from common abnormal hematopoietic stem cells.

Childhood myeloproliferative disorders

Disorders classified as paediatric myeloproliferative disorders (MPD), such as juvenile chronic myeloid leukaemia (JCML), and as paediatric myelodysplastic syndrome (MDS), are essentially diseases characterized by abnormal myeloproliferation and they share similar genetic events on chromosome 7. As such, the abnormalities of increased myeloproliferation in childhood (AIMC) should be considered under the same heading. Constitutional and other genetic factors play an essential role in children and include the NF1 gene, whereas toxic exposure is of greater importance in adults. The most common cytogenetic alteration is that of monosomy or deletion of the long arm of chromosome 7. Critical regions have been identified and mapped by fluorescence in situ hybridization (FISH). It appears that the similar critical regions on chromosome 7 are involved, and suggests that these regions may contain genes important in the pathogenesis of AIMC.

[Immunophenotype of blast crisis in chronic myeloid leukemia]

The blast crisis in chronic myeloid leukaemia (CML) is morphologically well defined. The aim of this report was to analyze whether immunophenotyping can divide CML blast crises into subtypes as is done in acute de novo leukaemia, and whether a specific CML pattern exists. Between 1991 and 1997 we reevaluated all the immunophenotypes of patients with CML blast crises with special regard to immunological subclassification, expression of CD34, presence of aberrant markers and number of immunological clusters. Twenty-nine CML blast crises were analyzed. Seventeen were myeloid, 11 lymphoid and one biphenotypic. The blast crises were divided into subtypes as de novo acute leukaemias: of the 17 myeloid blast crises 6 were undifferentiated, 5 differentiated and 6 had monocytic differentiation. In the lymphoid blast crises there were no pro-B, 8 common-B and 3 mature-B. No T-lymphoid blast crises were observed. In 26/29 analyses (90%) CD34 was expressed in the blasts. In 17/29 analyses (59%) one or two aberrant markers were found. In summary, immunophenotyping is important in distinguishing between myeloid and lymphoid blast crises. A subclassification, as in acute leukaemias, is possible. We found no specific immunophenotypic CML pattern. A study directly comparing immunophenotyping of CML blast crises with acute de novo leukaemia is planned.

On a mechanism for isochromatid 17q in a subset of Ph+ chronic myeloid leukemia patients

A mechanism for converting human chromatid 17 into its isoforms-isochromatid 17q and isochromosome X17q--is discussed. The frequency of these isoforms in a subset of Ph+ chronic myeloid leukemia patients is traceable to singularities of the nuclear envelope of myeloid cells. When statistically interpreted, loss of tumor suppressor gene (p53) seems less significant than additive retention of genes on the q arm of 17, at least regarding evolution of clones carrying both Ph and X17q markers.

Impact of clinical and morphological variables in classification and regression tree-based survival (CART) analysis of CML with special emphasis on dynamic features

To determine parameters of predictive value in CML, a retrospective clinico-pathological study was performed. This included laboratory data and (pretreatment) bone marrow biopsies of 120 patients with a monotherapy by busulfan (BU) and 50 patients with interferon-alpha 2b (IFN) treatment. Median survival in the BU group was 39 months and in the IFN-treated patients 65 months. Morphological features (CD61-positive megakaryocytes, argyrophilic fibres, pseudo-Gaucher cells) were evaluated by morphometry. Additionally, we measured the incidence of apoptosis (in situ end-labelling technique) and the expression of the proliferating cell nuclear antigen (PCNA). The ratio between the proliferative and apoptotic cell fraction was coined leukaemia turnover index (LTI). In order to estimate the impact of clinical and various morphological as well as dynamic features of prognostic significance, a multivariate analysis was carried out using the classification and regression tree approach (CART). Discrimination of single disease parameters revealed that fibrosis remained the most significant variable for survival in both therapeutic groups. Indicators of myeloid metaplasia such as occurrence of erythro-normoblasts and/or splenomegaly were important clinical parameters for prognosis. Inclusion of morphological as well as dynamic disease features in risk classification resulted in a substantial improvement of prognostic efficiency compared to other predictive scores which could be demonstrated by means of ROC-analysis.

A diagnostic dilemma: chronic myelomonocytic leukemia versus atypical chronic myeloid leukemia. A case report and review of the literature

There exists a great deal of overlap between many myelodysplastic syndromes and myeloproliferative disorders. This is most evident in the spectrum of disorders classified under the term chronic myeloid leukemia. These include chronic granulocytic leukemia, atypical chronic myeloid leukemia and chronic myelomonocytic leukemia. Current classification often does not clearly separate these entities since they share many features, both clinically and hematologically. We report here a case that satisfies criteria for both chronic myelomonocytic leukemia and atypical chronic myeloid leukemia, appearing to fluctuate between the two. This lends further evidence for the heterogeneity of these disorders and the need for better definition. An improved classification scheme would allow for more accurate reporting and research into etiology and treatment. The complex cytogenetic abnormalities of the case are unique and to our knowledge have not been reported previously. Also, this case report underscores the importance of cytochemical stains when such disorders are under consideration.

Atypical chronic myeloid leukemias

An ideal classification of the chronic myeloid leukemias would be based on a thorough understanding of the aetiology, pathogenesis, clinical and laboratory features, and natural history of the various conditions which comprise CML. Only in the case of CGL is the pathogenesis well understood and the diagnosis of the remaining disorders is still largely based on clinical and morphological criteria. It is inevitable for the reasons previously discussed that there will be cases which either defy classification or fall within the diagnostic criteria of more than one disorder. As long as careful clinical and morphological observation continues in parallel with advances in cellular and molecular biology it seems inevitable that the current debate about the inter-relationship between CMML, aCML and Philadelphia negative CGL will be resolved.

Immunological classification of chronic myeloid leukemia distinguishes chronic phase, imminent blastic transformation, and acute lymphoblastic leukemia

The clinical course of chronic myeloid leukemia (CML) is highly variable and therefore it is difficult to predict the duration of the chronic phase. We studied the immunological expression of maturation patterns in 62 cases of CML (30 cases in clinical/cytological blast crisis (BC), 32 cases in clinical/cytological chronic phase (CP) by means of a double marker enzyme immuno assay (DM-EIA). Immunological findings were supplemented by Southern blots using Ig-JH-, TCRbeta- and bcr-probes. Patients in BC (n = 30) expressed high proportions of CD10, CD20, CD33, CD34 and low degrees of a mature myeloid marker (CD15). Myeloid BC bone marrow (BM) cells showed a high degree of coexpression of unusual, lineage restricted markers: 25% of CD15-positive cells also expressed markers like CD10, CD20 or CD34. In contrast, BM cells in lymphoid BC did not show this coexpression. In CP two groups were distinguished immunologically: concordant cases which were immunologically normal (n = 14) and discordant cases (n = 18) which showed increased proportions of unusual, lineage restricted markers and double labelled cells (e.g. CD15/CD34). The latter group developed clinical BC earlier during further follow up (p = 0.009). Cases of lymphoid BC (n = 11)--in contrast to acute lymphoblastic leukemia (ALL) patients (n = 21)--did not show coexpression of CD15/CD10, CD20, CD34. These data show that blast clones can be detected in CML-CP by characteristic immunological maturation defects several months before the clinical onset of BC. Moreover, the lymphoid "blasts" of CML-BC represent a relatively differentiated lymphoid population of cells which can be distinguished from ALL by their lack of coexpression of unusual, lineage restricted markers.