Karyotypic Identification of Abnormal Clones Preceding Morphological Changes or Occurring with No Definite Morphological Features of Myelodysplastic Syndrome: A Preliminary Study

Clinical significance of acquired cytogenetic clones in patients with treated follicular lymphoma

BACKGROUND

Follicular lymphoma (FL) is the second most common B-cell non-Hodgkin lymphoma worldwide. In most patients, the disease is diagnosed at advanced stages and cannot be cured using conventional therapeutic approaches. To assess the role of cytogenetic abnormalities in therapy-related myeloid neoplasms (tMNs), we studied the clinicopathologic and cytogenetic features of treated FL patients who subsequently developed a new acquired cytogenetic clone (ACC).

PATIENTS AND METHODS

Twenty-five treated FL patients developed new cytogenetic abnormalities from 2009 to 2012. Patients were divided into 3 groups based on the presence and absence of tMNs: group 1, ACC without tMNs after a median follow-up of 15 months; group 2, ACC with possible tMN after silent ACC detection; group 3, tMNs present at the first ACC detection.

RESULTS

The most frequent cytogenetic aberrations involved chromosome 7. Compared with group 1, group 3 had significantly greater size of ACC, higher frequency of chromosome 7 aberrations, more likely showed dysplasia, and lower platelet count (P = .03).

CONCLUSION

Our results indicate that the presence of ACC alone is insufficient for diagnosis of tMNs. The proportion of cells with specific aberrations at first ACC, bone marrow dysplasia, and low platelet counts might predict outcome of ACC.

Clonal origin and evolution of myelodysplastic syndrome analyzed by dysplastic morphology and fluorescence in situ hybridization

Myelodysplastic syndromes (MDS) are clonal disorders of hematopoietic stem/progenitor cells. As bone marrow cells are extremely diverse in these disorders, the origin and evolution of MDS clones are difficult to identify and trace. Cellular dysplasia is a distinct morphologic feature; however, whether the dysplastic cells represent abnormal clones or only nonspecific superficial phenomena remains to be clarified. To address this question, 97 patients were examined for dysplasia features, among them bone marrow slides of 16 patients with chromosomal abnormalities were subjected to fluorescence in situ hybridization (FISH) to determine the karyotype of these dysplastic cells. Furthermore, the emerging frequencies of abnormal karyotypes in various differentiated stages of each lineage were also evaluated by a combination of morphological evaluation and FISH karyotyping. Our results indicate that the overall percentage of dysplastic cells does not differ significantly among the WHO subtypes, while the megakaryoid lineage presents the most frequent dysplasia in all subtypes. A positive correlation between dysplastic cells and FISH-detectable abnormal clones was observed, but the dysplastic morphology was not a specific feature of FISH-detectable abnormal clones. FISH-detectable abnormal clones can differentiate into mature granulocytes and erythrocytes, in coexistence with cells originating from the normal clones.

Altered hematopoietic cell gene expression precedes development of therapy-related myelodysplasia/acute myeloid leukemia and identifies patients at risk

Therapy-related myelodysplasia or acute myeloid leukemia (t-MDS/AML) is a major complication of cancer treatment. We compared gene expression in CD34+ cells from patients who developed t-MDS/AML after autologous hematopoietic cell transplantation (aHCT) for lymphoma with controls who did not develop t-MDS/AML. We observed altered gene expression related to mitochondrial function, metabolism, and hematopoietic regulation in pre-aHCT samples from patients who subsequently developed t-MDS/AML. Progression to overt t-MDS/AML was associated with additional alterations in cell-cycle regulatory genes. An optimal 38-gene PBSC classifier accurately distinguished patients who did or did not develop t-MDS/AML in an independent group of patients. We conclude that genetic programs associated with t-MDS/AML are perturbed long before disease onset, and accurately identify patients at risk for this complication.

Incidence and clinical characteristics of clonal cytogenetic abnormalities of acquired aplastic anemia in adults

Background

Cytogenetic abnormalities (CAs) have been reported frequently in patients with otherwise typical aplastic anemia (AA), but their implications in the prognosis and in the evolution to hematologic malignancies are controversial.

Methods

We retrospectively analyzed 127 adult AA patients who had successful cytogenetic analysis at initial diagnosis.

Results

The patients were classified into 3 groups according to the initial and follow-up results of cytogenetic profiles. Group 1 included patients who had persistent AA with normal cytogenetic profiles (N=117); Group 2, those who had a normal cytogenetic profile at initial diagnosis but later acquired CA (N=4, 3.1%); and Group 3, those who had CA at the initial diagnosis, regardless of follow-up cytogenetic status (N=6,4.7%). In Group 2, 2 patients later developed CA without progression to acute myeloid leukemia (AML) or myelodysplastic syndrome (MDS); the other 2 patients later progressed to AML. None of the patients in Group 3 progressed to AML or MDS. There was no significant difference in overall survival between Groups 1 and 3.

Conclusion

AA patients with CA at initial diagnosis or follow-up may not be at greater risk for evolution to AML or MDS, or show shorter survival periods. Prospective studies and a larger patient samples are needed to establish the clinical relevance of CA.

Transient myelodysplastic syndrome in X-linked agammaglobulinemia with a novel Btk mutation

X-linked agammaglobulinemia (XLA) is a rare disorder in which recurrent infections occur due to low serum globulins and circulating B lymphocytes caused by a mutation in the Bruton tyrosine kinase (Btk) gene. While myelodysplastic syndrome (MDS) associated with low B lymphocyte counts has been described, clonal cytogenetic abnormalities in confirmed cases of XLA have never been reported. We describe a case of XLA with a novel Btk mutation who also had a persistent clonal population in the bone marrow with abnormal cytogenetics in multiple chromosomes that resolved 1(1/2) years after treatment with IVIG, mimicking a picture of transient MDS.