Ph1-positive and Ph1-negative abnormal cell lines in a child with lymphoblastic lymphoma

BCR-ABL1 gene rearrangement as a subclonal change in ETV6-RUNX1-positive B-cell acute lymphoblastic leukemia

We report here on a case of ETV6-RUNX1-positive B-cell acute lymphoblastic leukemia (B-ALL) that has acquired a BCR-ABL1 gene rearrangement as a subclonal change. The 19-year-old female patient presented with B symptoms, pancytopenia, and circulating blasts. The bone marrow aspirate was hypercellular and was infiltrated by an immature blast population that was confirmed as B-ALL by flow cytometry. Sequential fluorescent in situ hybridization was performed on the patient's leukemic cells, which were shown to contain both ETV6-RUNX1 and BCR-ABL1 gene rearrangements. The majority of nuclei (85%) showed only the ETV6-RUNX1 gene rearrangement; however, an additional 10% also showed a variant BCR-ABL1 gene rearrangement, indicating the ETV6-RUNX1 gene rearrangement was the primary change. A review of the literature has shown that acquisition of a BCR-ABL1 gene rearrangement as a secondary change in B-ALL is a very rare occurrence, and the effect it may have on prognosis is uncertain in the modern therapy age.

Philadelphia-chromosome-positive T-lymphoblastic leukemia: acute leukemia or chronic myelogenous leukemia blastic crisis

The Ph1 chromosome has rarely been reported in T-lineage acute lymphoblastic leukemia (T-ALL), and the clinical relevance of this translocation in T-ALL is currently unknown. In chronic myelogenous leukemia (CML) some data indicate derivation of T-cells from the leukemic clone and only a few cases of T-derived blastic crisis have been reported and quite often disputed. Particularly in cases identified initially in blastic crisis it may be difficult to distinguish those from Ph1-positive T-ALL. We herein report 2 patients who presented with a clinical picture of Ph1-positive T-ALL and who raised a differential diagnosis from T-cell blastic crisis of CML. We review the literature and suggest clinical and laboratory features that can help in the diagnosis. According to our literature review, 23 cases of Ph1-positive T-ALL and 44 cases of T-cell blastic crisis of CML, including ours, were reported. Some major differences between the two entities could help in establishing a diagnosis of Ph1-positive T-cell blastic crisis of CML vs. Ph1-positive T-ALL: Male sex and younger age was more predominant in T-ALL. While in most cases of CML blastic crisis there was a history of CML there was no such history in the T-ALL cases. Medullary involvement with lymphoblastic leukemia was present in all cases of T-ALL but only in about half of the cases of CML blastic crisis. None of the CML-blastic crisis cases tested by RT-PCR showed the minor breakpoint transcript, while 2 cases with T-ALL had the minor breakpoint transcript and 1 had both transcripts. Combined morphologic and FISH analysis can help to distinguish between the two entities and was applied in one of our cases. Although both entities carry a severe prognosis, differentiating between them might have clinical relevance, especially in the imatinib era.

Novel genomic imbalances in B-cell splenic marginal zone lymphomas revealed by comparative genomic hybridization and cytogenetics

Splenic marginal zone lymphoma (SMZL) has recently been recognized in the World Health Organization classification of hematological diseases as distinct type of non-Hodgkin's lymphoma. In contrast to the well-established chromosomal changes associated with other B-cell non-Hodgkin's lymphoma, few genetic alterations have been found associated with SMZL. The aim of our study was to analyze by comparative genomic hybridization (CGH) the chromosomal imbalances in 29 patients with SMZL and to correlate these findings with clinical and biological characteristics and patient outcome. In 21 cases, cytogenetic studies were simultaneously performed. Most of the patients (83%) displayed genomic imbalances. A total of 111 DNA copy number changes were detected with a median of four abnormalities per case (range, 1 to 12). Gains (n = 92) were more frequent than losses (n = 16), while three high-level amplifications (3q26-q29, 5p11-p15, and 17q22-q25) were observed. The most frequent gains involved 3q (31%), 5q (28%), 12q and 20q (24% each), 9q (21%), and 4q (17%). Losses were observed in 7q (14%) and 17p (10%). SMZL patients with genetic losses had a shorter survival than the remaining SMZL patients (P < 0.05). In summary, chromosomal imbalances in regions 3q, 4q, 5q, 7q, 9q, 12q, and 20q have been detected by CGH in SMZL. Patients with SMZL displaying genetic losses by CGH had a short survival.

Cytogenetic characteristics of childhood non-Hodgkin lymphoma

Cytogenetic studies were performed successfully on 24 patients with non-Hodgkin lymphoma (NHL) who were younger than 15 years of age. Of these, 22 patients (92%) had abnormal clones. With respect to histologic findings, 3 (25%) of the 12 patients with lymphoblastic lymphoma had 14q11 translocations and 2 (17%) had t(9;17) (q34;q23). Four (80%) of the five patients with small non-cleaved cell lymphoma had t(8;14)(q24;q32). With respect to immunologic findings, four (44%) of the nine patients with T-cell lymphoma had abnormalities consisting of 14q11 and 7q36 translocations, in which the T-cell receptor genes resided. Three (33%) of the patients with T-cell lymphoma had t(9;17)(q34;q23). However, three (43%) of the seven patients with B-cell lymphoma had t(8;14) (q23;q32), and two (29%) of the patients with B-cell lymphoma had an extra i(11q) chromosome with a resultant 11q tetrasomy. Non-T-cell non-B-cell lymphomas, which occurred in 21% of all patients, showed various chromosomal abnormalities. This study demonstrated that, in childhood NHL, karyotype correlates closely with immunophenotype, clinical features, and histologic findings.

Extramedullary blast crisis in chronic myelogenous leukemia. Demonstration of T-cell lineage and Philadelphia chromosome in a paraspinal tumor

A case of chronic myelogenous leukemia (CML) with penetrance of the Ph1 molecular alteration into the T-cell lineage of a paraspinal tumor is reported. The T-cell nature of the paraspinal tumor was documented by immunochemical study and genotyping. The Philadelphia chromosome was also detected by genotyping in the same tumor cell population. To the authors' knowledge, this is the first case of extramedullary T-cell blast crisis in CML demonstrated in an extranodal tumor. The clinical significance of detecting extramedullary blast crisis, and the theories for the scarcity of T-cell transformation in CML are discussed.

T-cell involvement in benign phase chronic myelogenous leukemia

T cells from the peripheral blood of patients with chronic myeloid leukemia (CML) were cultured with phytohemagglutinin and T-cell growth factor (TCGF) in agar culture. These T-cell colonies were pooled and expanded further in liquid culture with TCGF and then simultaneously analysed for the E-rosette receptor with the monoclonal antibody OKT11 and for the presence of the Philadelphia (Ph1) chromosome. OKT11 analysis showed these populations to be composed 99.5% or more of T cells. In four of the seven patients the T-cell suspension showed 7/50 (14%), 3/36 (8%), 2/34 (6%), and 4/44 (9%) Ph1 metaphases. Furthermore, Ph1 metaphases were demonstrated in T-cell cultures in two patients when bone marrow metaphases simultaneously showed 90 and 100% Ph1 negative metaphases secondary to human leukocyte interferon therapy or combination chemotherapy. A minority of T cells in benign phase CML have the Ph1 abnormality despite reduced number of Ph1 metaphases in bone marrow from therapy.