Distribution of cytogenetic abnormalities in myelodysplastic syndromes, Philadelphia negative myeloproliferative neoplasms, and the overlap MDS/MPN category.

According to the new World Health Organization (WHO) classification (2008), chronic myeloid malignancies are divided in myeloproliferative neoplasms (MPN), myelodysplastic syndromes (MDS), and overlap MDS/MPN cases. From morphological aspects, these categories show overlaps. To evaluate whether these morphological similarities have genetic parallels, we investigated 1,851 cases with suspected/confirmed myelodysplastic or myeloproliferative diseases by chromosome banding and molecular analyses. Cytogenetics revealed aberrant karyotypes in 354 patients (19.1% of the original cohort) who were the basis of further analysis. The distribution of chromosomal aberrations differed significantly between categories. Isolated +9 and gain of 9p were exclusively observed in MPN (+9: 10/93; 11%; p < 0.001; +9p: 6/93; 7% of all aberrant MPN cases) but were not detected in MDS or MDS/MPN (p = 0.001). Isolated del(5q) (p = 0.002), -7 in combination with other aberrations (p = 0.016), and complex aberrations (p = 0.003) were 2.9- to 7.5-fold more frequent in MDS than in MPN. Trisomies 8 and 21 and del(20q) were comparably frequent in both subgroups. Interestingly, the MDS/MPN overlap cohort showed a higher frequency of -7 accompanied by other aberrations (3/17; 18% of all aberrant cases; p = 0.001), i(17)(q10) (2/17; 12%; p = 0.013), and +21 (2/17; 12%; p = 0.013) when compared to MPN or MDS only. These differences support the category for MDS/MPN within the new WHO classification. Overlaps between the diverse disorders were seen also for the JAK2V617F (MPN 66/89; 74%; MDS/MPN 4/14; 29%; MDS 2/63; 3%) and NRAS mutations (MDS 2/67; 3%; MPN 2/4; MDS/MPN 1/1). In conclusion, cytogenetics and molecular genetics show overlaps in varying proportions of MDS and MPN cases which might indicate common pathways in their etiology. Some markers are strongly associated with one of these disorders and can be helpful for differential diagnosis especially in difficult cases.

Atypical chronic myeloid leukemia as defined in the WHO classification is a JAK2 V617F negative neoplasm.

Atypical chronic myeloid leukemia (aCML) as defined by the WHO classification is a rare hematopoietic stem cell disorder, which shows both myeloproliferative as well as myelodysplastic features. Because of the presence of neutrophilic leukocytosis, aCML may resemble chronic myelogenous leukemia. However, in contrast with the latter, aCML lacks a Philadelphia chromosome or the BCR/ABL fusion gene. The molecular pathogenesis of aCML and its relationship to other myeloproliferative neoplasms is unknown. To clarify these points, the presence of JAK2 V617F was examined by a retrospective analysis of archival specimens obtained from two large medical institutions. Paraffin-embedded bone marrow (BM) trephines and clot sections were examined by an allele-specific TaqMan PCR suitable for use with decalcified tissue. Fifty-nine cases of Philadelphia (Ph) chromosome negative chronic myeloproliferative neoplasms (CMPN) and normal bone marrows (BM) served as controls. None of the nine amplifiable cases of aCML and none of the normal BM controls showed a JAK2 V617F mutation, in contrast to 45/59 (76%) of the Ph chromosome negative CMPN cases. Atypical CML should therefore be considered as a JAK2 negative chronic myeloid neoplasm that remains properly categorized, alongside chronic myelomonocytic leukemia and juvenile myelomonocytic leukemia, within the WHO group of myelodysplastic/myeloproliferative neoplasms.

BCR-ABL-negative chronic myeloid leukemia.

Constitutive activation of protein tyrosine kinases plays a central role in the pathogenesis of myeloproliferative disorders, including BCR-ABL-negative chronic myeloid leukemia. Current research is focused on elucidating the full spectrum of causative mutations in this rare, heterogeneous disease. Activated tyrosine kinases are excellent targets for signal transduction therapy, and an accurate diagnosis including morphology, karyotyping, and molecular genetics will become increasingly important to direct individualized treatment. In addition, new molecular findings need to be incorporated into disease classification systems.

Clonal lymphocytic populations in Philadelphia-negative chronic myeloproliferative disorders: is the T-cell clonality of 'undetermined' significance (TCUS) linked to a worse clinical outcome?

This study examined the clonality of B- and T-cells by PCR in 83 patients with Philadelphia-negative myeloproliferative disorders (Ph-MPD), to investigate its clinical and morphological correlates. Clonal lymphocytic populations were found in 23% of patients (T: n = 20, B: n = 3), with no frequency differences between ET, CIMF and PV. At the presentation, patients with clonal bands were older (58.1+/-13.8 vs 47.5+/-14.6, p = 0.0039), but did not differ in other clinical parameters. After the median follow-up of 21 months they were less likely to be asymptomatic (11.8% vs 41.1%, p = 0.029). The T-cell clonality was the strongest predictor of the symptomatic last follow-up by discriminant function analysis, surpassing the patient's age. This surprising negative prognostic impact of lymphocyte clonality in Ph-MPD may result from this phenomenon to be a better measure of the 'hematopoietic biologic age' than the metrical age itself.

[Diagnostic spectrum of Philadelphia-chromosome negative leukemic disorders]. / Differenzialdiagnose der Philadelphia-Chromosom-negativen leukämoiden Erkrankungen.

The spectrum of Philadelphia-chromosome negative leukemoid disorders displays a large heterogeneity of clinical and morphological findings at presentation. According to the FAB guidelines as well as the WHO classification, independent subtypes with different morphological features can be distinguished. In particular, based on the degree of dysgranulopoiesis, the extent of monocytosis, basophilia and the amount of immature and mature granulocytes in the peripheral blood and the percentage of erythroblasts, most of these cases can be correctly classified as either atypical chronic myeloid leukemia (aCML) or chronic myelomonocytic leukemia (CMML). An increase in immature and dysplastic granulocytes in the blood films at presentation accompanied by granulocytic dysplasia, is the most important diagnostic parameter of aCML. On the other hand, CMML is characterized by absolute monocytosis and, as explicitly outlined by the WHO classification, may show myelodysplastic and myeloproliferative features. However, in the absence of characteristic cytogenetic or molecular abnormalities for both diseases, a minority of patients still remain who are difficult to assign to a distinctive entity, since they either show overlapping features or do not fulfill the whole set of diagnostic criteria. Furthermore, controversy and discussion arise about aCML with monocytosis and its association to CMML. Finally, leukemoid reactions and the very rarely encountered chronic neutrophilic leukemia (CNL) should be considered in patients with chronic leukocytosis. In conclusion, careful morphological analysis of bone marrow histology as well as peripheral blood films and bone marrow smears, enables the identification of patients with different prognosis and therapeutic response.

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.

[Histopathology of Ph1-negative chronic myeloproliferative diseases]. / Histopathologie der Ph1-negativen chronischen Myeloproliferativen Erkrankungen.

The Ph1-negative groups of chronic myeloproliferative diseases (CMPD) are described, and histopathological criteria that distinguish them from each other are given. These are based upon observations in primary biopsies from 2,331 patients with CMPDs among a total of 34,160 patients referred between 1 January 1989 and 30 June 1994 to the Bone Marrow Registry. These cases of CMPD break down into the main groups as follows: CML 23.2%, megakaryocytic myelosis consistent with agnogenic myeloid metaplasia 22.3%, essential thrombocythemia 22.1%, and polycythemia vera 20.4%; 12.0% of cases were unclassifiable. Histological progress in each group is characterized by (1) increasing number and pleomorphy of megakaryocytes, (2) increasing fibrosis, and (3) excess of blasts. These three features can be observed in diagnostic biopsies before any therapy. Therefore, it is recommended that such alterations be reported semiquantitatively. A staging system with four stages from 0 to 3 for each of the three features is introduced. Its application allows staging for the individual patient on the basis of diagnostic biopsies.

In vitro marrow purging in chronic myelogenous leukemia: effect of mafosfamide and recombinant granulocyte--macrophage colony-stimulating factor.

Clinical and experimental evidence revealing Ph1-negative hematopoietic stem cells in the majority of chronic myelogenous leukemia (CML) patients, suggests that autologous bone marrow transplantation (ABMT) may represent a therapeutic approach for these patients. It was the aim of the present study to evaluate the efficacy of the cyclophosphamide derivative mafosfamide as a marrow purging agent in a group (n = 15) of CML patients. Chemical purging was followed by a short-term liquid culture phase supplemented with recombinant granulocyte-macrophage colony-stimulating factor (rGM-CSF). Mafosfamide (100 micrograms/ml) incubation induced a marked inhibition of progenitor cell growth, the percentages of surviving CFU-GEMM, BFU-E, and CFU-GM being 3.4, 5.4, and 4.9, respectively. At the cytogenetic level, the purging procedure failed to show any modulating effect on Ph1-negative clones in 9/15 cases. In contrast, 6/15 cases showed a significant increase in the mean (+/- SD) percentage of Ph1-negative metaphases in response to rGM-CSF (46 +/- 26, p less than or equal to 0.05), mafosfamide incubation (53 +/- 12, p less than or equal to 0.01), and the combination of mafosfamide incubation plus rGM-CSF (63 +/- 29, p less than or equal to 0.025). Immunological analysis revealed that mafosfamide incubation induced a significant enrichment of MY10 (28 +/- 9, 0.05) B73.1-positve cells (25 +/- 9, p less than or equal to 0.05). Four mafosfamide-responsive patients with CML in second chronic phase have been autografted with mafosfamide purged marrow. In all patients a Ph1-negative phase lasting 5-14 months was observed. In conclusion, it appears that (a) in a subgroup of CML patients mafosfamide purging is effective in reducing the size of the malignant clone and might induce through its cytotoxic and immune actions a modification of the balance between leukemic and normal clones, and (b) this experimental approach may be used as a screening test to select patients to undergo marrow harvest and ABMT with mafosfamide purged marrow.