Refractory cytopenia with t(1;7),+8 abnormality and dysplastic eosinophils showing intranuclear Charcot-Leyden crystals: a fluorescence in situ hybridization study

The der(1;7)(q10;p10) defining a distinct profile from -7/del(7q) in myelodysplastic syndromes: A systematic review and meta-analysis

BACKGROUND AND OBJECTIVE

Myelodysplastic syndromes (MDS) are myeloid neoplasms characterized by ineffective hematopoiesis due to stem cell abnormalities. Monosomy 7q aberrations are a common cytogenetic abnormality in MDS. Specifically, an unbalanced translocation der(1;7)(q10;p10) [der(1;7)] has been identified in MDS patients, which is a monosomy 7q aberration variant like -7/del(7q). However, knowledge of der(1;7)'s features remains limited. Existing studies have compared the clinical and genetic characteristics of der(1;7) to those of -7/del(7q) but yielded inconsistent findings. Accordingly, we conducted meta-analyses comparing der(1;7) to -7/del(7q).

METHODS

Publications were searched from the following databases up to January 10, 2023: Pubmed, Web of Science, Embase, Cochrane, and ClinicalTrials.gov. Eligible studies were assessed for risks of bias. Relevant data were extracted from included studies and analyzed using random-effects models. Publication bias was evaluated and sensitivity analyses were performed.

RESULTS

The comparative meta-analyses included 405 MDS patients with der(1;7) from nine studies. The analysis revealed that der(1;7) was associated with a greater male preponderance (86.1% vs. 68.3%, Odds Ratios (ORs) 2.007, p < 0.01) than -7/del(7q), lower platelets counts compared to del(7q), higher hemoglobin levels than -7, lower absolute neutrophil counts, and higher percentage of patients with non-excess blasts (66.9% vs. 41.3%, ORs 2.374, p = 0.01) in comparison with -7/del(7q). The der(1;7) existed more as a sole karyotype aberration (55.6% vs. 37.0%, ORs 2.902, p = 0.02), co-occurred more often with +8 (22.7% vs. 4.2%, ORs 5.714, p = 0.04) whereas less -5/del(5q) (1.5% vs. 41.3%, ORs 0.040, p < 0.01) and complex karyotype (7.3% vs. 54.8%, OR 0.085, p < 0.01). The der(1;7) was associated with higher frequencies of RUNX1 (40.8% vs. 12.3%, ORs 4.764, p < 0.01), ETNK1 (28.1% vs. 2.5%, ORs 42.106, p < 0.01) and EZH2 (24.8% vs. 6.9%, ORs 3.767, p = 0.02) mutations, but less TP53 mutation (2.4% vs. 45.3%, ORs 0.043, p < 0.01). Moreover, der(1;7) patients had longer time to progression (Hazard Ratios (HRs) 0.331, p = 0.02), better overall survival (OS) than -7 patients (HRs 0.557, p < 0.01), but similar OS with del(7q) patients (HRs 0.837, p = 0.37).

CONCLUSION

The findings revealed distinct clinical, cytogenetic, and molecular characteristics distinguishing der(1;7) from -7/del(7q), indicating der(1;7) defines a unique subtype within MDS with monosomy 7q. These findings support classifying der(1;7) as a separate MDS entity in future.

A Brief History of Charcot-Leyden Crystal Protein/Galectin-10 Research

Eosinophils are present in tissues, such as the respiratory tract, spleen, lymph nodes and blood vessels. The significant presence of eosinophils in these tissues are associated with various diseases, including asthma, allergies, acute myeloid leukemia, etc. Charcot-Leyden crystal protein/galectin-10 is overexpressed in eosinophils and has also been identified in basophils and macrophages. In human body, this protein could spontaneously form Charcot-Leyden crystal in lymphocytes or in the lysates of lymphocytes. At present, the role of Charcot-Leyden crystal protein/galectin-10 in lymphocytes is not fully understood. This review summarizes research progress on Charcot-Leyden crystal protein/galectin-10, with emphasis on its history, cellular distributions, relations to diseases, structures and ligand binding specificity.

Does MDS with der(1;7)(q10;p10) constitute a distinct risk group? A retrospective single institutional analysis of clinical/pathologic features compared to -7/del(7q) MDS

The der(1;7)(q10;p10) aberration is observed in about 1-3% of the myelodysplastic syndromes (MDS) and less commonly in acute myeloid leukemia (AML) and the myeloproliferative disorders. This unbalanced translocation is considered a "variant" of the del(7q)/-7 subgroup and has been assigned a poor risk karyotype score in the MDS International Prognostic Scoring System (IPSS). Recent reports suggest der(1;7) MDS should be considered a discrete MDS subgroup with an intermediate, not poor, karyotype score. At the City of Hope, we compared the clinical-pathologic features of 12 der(1;7) MDS patients to 51 MDS patients with del(7q) (n=10) or -7 (n=41), selected for a similar frequency of secondary aberrations. The der(1;7) patients showed older age at diagnosis, lower platelet counts, less trilineage dysplasia, and lower blast counts. The der(1;7) patients did not differ from del(7q)/-7 patients in subtypes of MDS by World Health Organization, French-American-British classifications, or bone marrow cellularity. Neither the proportion of therapy-related MDS nor the transformation to AML differed significantly among the three subgroups. Five-year survival rates for der(1;7), del(7q), and -7 (44.4, 32.0, and 23.6%, respectively) did not differ significantly (P=0.94). While der(1;7) MDS is associated with some clinically distinctive features, reassignment of risk category based on these data would be premature.

Eosinophilic disorders

Eosinophilic inflammatory responses occur in association with multiple disorders. Although the initial cause and the affected organs vary among the different eosinophilic disorders, there are only 2 major pathways that mediate eosinophilia: (1) cytokine-mediated increased differentiation and survival of eosinophils (extrinsic eosinophilic disorders), and (2) mutation-mediated clonal expansion of eosinophils (intrinsic eosinophilic disorders). Independent from the original trigger, the most common cause of eosinophilia is the increased generation of IL-5-producing T cells. In some cases, tumor cells are the source of eosinophil hematopoietins. The intrinsic eosinophilic disorders are characterized by mutations in pluripotent or multipotent hematopoietic stem cells leading to chronic myeloid leukemias with eosinophils as part of the clone. Here, we propose a new classification of eosinophilic disorders on the basis of these obvious pathogenic differences between the 2 groups of patients. We then discuss many known eosinophilic disorders, which can be further subdivided by differences in T-cell activation mechanisms, origin of the cytokine-producing tumor cell, or potency of the mutated stem cell. Interestingly, many subgroups of patients originally thought to have the idiopathic hypereosinophilic syndrome can be integrated in this classification.

A case of chronic myelomonocytic leukemia with severe eosinophilia having t(5;12)(q31;p13) with t(1;7)(q10;p10)

We describe an unusual case of chronic myelomonocytic leukemia with severe eosinophilia having t(5;12)(q31;p13) with t(1;7)(q10;p10). The eosinophilic proliferation was severe in peripheral blood and bone marrow, and they revealed marked dysplastic features. We performed fluorescence in situ hybridization (FISH) and immunohistochemistry to evaluate the clonality of eosinophils. The eosinophils were stained positively to platelet-derived growth factor receptor-beta. By FISH using chromosome 1 satellite probe and chromosome 1q telomere probe, the eosinophils were proved to belong to the malignant clone.

Prevalence and clinical characteristics of myelodysplastic syndrome with bone marrow eosinophilia or basophilia

By retrospectively analyzing 288 patients with de novo myelodysplastic syndrome (MDS), we sought to determine the prevalence and clinical characteristics of bone marrow eosinophilia and basophilia that were detected at presentation. Bone marrow eosinophilia and basophilia were defined as a differential count of each cell type exceeding 5.0% and 1.0%, respectively. Of 288 patients with MDS, 36 (12.5%) fulfilled this criterion for bone marrow eosinophilia (MDS-Eos); 34 patients (11.8%) showed basophilia (MDS-Bas), and 11 (3.8%) satisfied both criteria (MDS-EosBas). The remaining 229 patients had neither eosinophilia nor basophilia in their bone marrow (MDS(-/-)) at presentation. Cytogenetic analysis was carried out on unstimulated bone marrow cells obtained from 264 patients. When the cytogenetic categorization of the IPSS (International Prognostic Scoring System) for MDS was applied, significantly higher numbers of MDS-Eos and MDS-Bas patients had chromosomal abnormalities carrying intermediate or poor prognosis, compared with the MDS(-/-) patients. Specific chromosomal abnormalities and complex karyotypes were associated with MDS-Eos and/or MDS-Bas. In accordance with these results, the overall survival rate was significantly lower, and the evolution to acute myelogenous leukemia (AML) occurred more frequently in the MDS-Eos and MDS-Bas than in the MDS(-/-) patients. Multivariate analysis demonstrated that bone marrow basophilia was an independent risk factor for evolution to AML. Our study indicates that bone marrow eosinophilia and basophilia in patients with MDS predict a poorer prognosis.

Waldenström macroglobulinemia with a novel der(8;17)(q10;q10)

We report the occurrence of an unbalanced whole-arm translocation of der(8;17)(q10;q10) in an 80-year-old female patient with Waldenström macroglobulinemia. To our knowledge, der(8;17)(q10;q10) has not been described in Waldenström macroglobulinemia. Although this cytogenetic abnormality has been reported in a number of solid tumors, a literature review suggests also a possible association with B-cell chronic lymphoproliferative disorders.

Late appearance of t(1;19)(q11;q11) in myelodysplastic syndrome associated with dysplastic eosinophilia and pulmonary alveolar proteinosis

We report a case of myelodysplastic syndrome (MDS), which developed marked eosinophilia and pulmonary alveolar proteinosis after the appearance of t(1;19)(q11;q11). Chromosomal analysis of the peripheral eosinophils identified the same chromosome abnormality in all metaphases to that of bone marrow blast cells. Review of the literature revealed three reported cases of concurrent MDS and pulmonary alveolar proteinosis. We reviewed four cases of concurrent MDS and pulmonary alveolar proteinosis, including the present case. Interestingly, all but one of these patients also had evidence of eosinophilia and abnormality of chromosome 1p. These findings, together with morphologic abnormalities of eosinophils observed in this case, indicate clonal involvement of eosinophils in the MDS clone, and that the eosinophilia was derived from the neoplastic clone with the translocation. We postulate that this chromosomal rearrangement is involved in the development of eosinophilia and pulmonary alveolar proteinosis in MDS.

Familial partial monosomy 7 and myelodysplasia: different parental origin of the monosomy 7 suggests action of a mutator gene

Two sisters are reported, both with a myelodysplastic syndrome (MDS) associated with partial monosomy 7. A trisomy 8 was also present in one of them, who later developed an acute myeloid leukemia (AML) of the M0 FAB-type and died, whereas the other died with no evolution into AML. Besides FISH studies, microsatellite analysis was performed on both sisters to gather information on the parental origin of the chromosome 7 involved in partial monosomy and of the extra chromosome 8. The chromosomes 7 involved were of different parental origin in the two sisters, thus confirming that familial monosomy 7 is not explained by a germ-line mutation of a putative tumor-suppressor gene. Similar results were obtained in two other families out of the 12 reported in the literature. Noteworthy is the association with a mendelian disease in 3 out of 12 monosomy 7 families, which suggest that a mutator gene, capable of inducing both karyotype instability and a mendelian disorder, might act to induce chromosome 7 anomalies in the marrow. We postulate that, in fact, an inherited mutation in any of a group of mutator genes causes familial monosomy 7 also in the absence of a recognized mendelian disease, and that marrow chromosome 7 anomalies, in turn, lead to MDS/AML.

The relationship between the myelodysplastic syndromes and the myeloproliferative disorders

As a result of clonal evolution typical cases of one of the myelodysplastic syndromes may develop myeloproliferative features. Similarly, typical cases of one of the myeloproliferative disorders may develop dysplastic features, either as part of the natural history of the disease or as a result of exposure to mutagenic drugs or isotopes. There is also an important group of "overlap syndromes" in which cases, at presentation, have both dysplastic and proliferative features. Chronic myelomonocytic leukaemia and many cases of atypical chronic myeloid leukaemia, juvenile chronic myeloid leukaemia and the childhood monosomy 7 syndrome are "overlap syndromes". In addition, a significant minority of cases which fit the generally agreed criteria for a diagnosis of one of the myelodysplastic syndromes (refractory anaemia, refractory anaemia with ring sideroblasts or refractory anaemia with excess of blasts) also have thrombocytosis, neutrophilia, monocytosis, eosinophilia or basophilia.

Near-haploid common acute lymphoblastic leukaemia of childhood with a second hyperdiploid line: a DNA ploidy and fluorescence in-situ hybridization study

Near-haploidy is a rare cytogenetic finding in childhood acute lymphoblastic leukaemia (ALL) and is associated with a poor prognosis. A second hyperdiploid line, occurring presumably by endoreduplication of the near-haploid stemline, is often observed. We present a case of common ALL in relapse characterized morphologically by a dual population of small and large lymphoblasts. Cytogenetic analysis supplemented with fluorescence in-situ hybridization (FISH) studies localized near-haploidy and hyperdiploidy to the small and large blast population respectively. DNA ploidy determination confirmed two abnormal clones with near-haploidy as the predominant one. A novel t(9;12)(q11;q13) was present in the near-haploid clone and was duplicated in the hyperdiploid clone. This finding identified cells bearing near-haploidy to be the clonogenic population following malignant transformation and confirmed endoreduplication as the mechanism for the presence of associated hyperdiploidy.

Myelodysplastic syndrome with hypereosinophilia and a nonrandom chromosomal abnormality dic(1;7): confirmation of eosinophil clonal involvement by fluorescence in situ hybridization

We report a case of de novo myelodysplastic syndrome (MDS) with hypereosinophilia and dic(1;7) in which eosinophil clonal involvement was confirmed by fluorescence in situ hybridization. There have been two previous reports in the literature of eosinophilic MDS with dic(1;7) or t(1;7) in which eosinophil clonality was demonstrated. The specific breakpoints on chromosomes 1 and 7 differ in the three cases, making it difficult to implicate disruption of a single gene as causative; nevertheless, the nonrandom occurrence of t(1;7) or dic(1;7) with malignant eosinophilic proliferations suggests that this chromosomal rearrangement is involved in the etiology of the disease.

The ultrastructural findings of Charcot-Leyden crystals in stroma of mastocytoma

Charcot-Leyden crystals (CLCs) have been found in many conditions associated with eosinophilia, but their occurrence in skin diseases is very rare. We report ultrastructural observations on the presence of CLCs in the cutaneous lesions of two cases of mastocytoma. Electron microscopy documented CLCs located in phagosomes of morphologically activated macrophages as well as free CLCs in the stromal tissue, close association between CLCs formation and damaged and lysed eosinophils was present. These findings provided evidence that the formation of CLCs in mastocytoma implicated the individual and interrelated biology of mast cells, eosinophils and macrophages. Phagosomes probably acted as the site of CLCs formation. The clinic and pathologic role of CLCs in mastocytoma deserves further investigation.

Special cytological subtypes of acute myeloid leukaemias and myelodysplastic syndromes

The recognition of distinct cytoimmunological subsets of pre-leukaemia and overt AML has been accomplished by morphological, immunological and ultrastructural studies. In many cases, a strong association has been documented between distinctive cytological features and specific chromosome changes. The primary genetic event underlying malignant transformation was also elucidated in a number of acute leukaemias and, as a matter of fact, assessment of these biological parameters has now an established role in the diagnostic work-up and in the monitoring of residual disease. On a more general basis, biological research in MDS is gradually clarifying the fundamental pathophysiological mechanisms of altered cell growth, and differentiation and therapeutic decision making in leukaemia is becoming increasingly dependent on the precise characterization of blast cells. Further refinement of the cytoimmunological classification of acute leukaemias and MDS is warranted in order to provide the physician with an updated framework of reference for the categorization of these heterogeneous haematological disorders and to improve the reproducibility of current morphological diagnosis among different centres (Castoldi et al, 1993).