Makoto Katsuno

Late‐appearing Philadelphia chromosome in a patient with acute nonlymphocytic leukaemia derived from myelodysplastic syndrome: detection of P210‐ and P190‐type bcr/abl fusion gene transcripts at the leukaemic stage

Summary. We describe a patient with acute nonlymphocytic leukaemia (ANLL) derived from myelodysplastic syndrome in whom the Philadelphia chromosome (Ph1) first emerged at the late stage of ANLL transformation. Cytogenetically, the Ph1 chromosome was not detected until the late stage of ANLL transformation, 14 months after the transformation following a 3‐month history of refractory anaemia with excess of blasts. The cells with and without the Ph1 chromosome had a common abnormal chromosome, t(3;3) (q21;q26). The reverse transcription‐polymerase chain reaction analysis showed no bcr/abl message at diagnosis. However, the mRNA encoding P210bcr/abl was detected in the early stage of ANLL transformation. Furthermore, the mRNAs encoding both P210bcr/abl and P190bcr/abl were detected in the late stage of ANLL transformation when the Ph1 chromosome was detected by cytogenetic analysis. These evidences support a multistep pathogenesis of leukaemias, and the product of bcr/abl fusion gene may influence the course of disease.

Clinical significance of human bone marrow stromal cell colonies in acute leukemias.

Human bone marrow-derived fibroblastoid colony-forming cells (CFU-F) and adipocyte colonies in 36 patients with acute leukemia were studied, and were serially analysed at different clinical stages. At untreated stage, CFU-F number in acute lymphoblastic leukemia (ALL) was lower than that in acute non-lymphoblastic leukemia (ANL). In ANLs, CFU-F number in M1 was lower than that in M2. Adipocyte colonies were frequently developed at regenerating and relapsing stages, but rarely at untreated and remission stages. The adipocyte colony formation did not correlate with any of CFU-F number, marrow cellularity nor number of leukemic cells, but might be associated with hemopoietic regeneration. The favorable prognosis was associated with normal CFU-F number and with adipocyte colony formation at regenerating or bottom stage. As adipocytes in marrow samples were completely removed before cultures, adipocyte colony was probably originated from preadipocytes. Thus, our results suggest that adipocyte precursor cells increase in regenerating marrow and that they are essential in active hemopoiesis.

Hematopoietic growth factors (BPA and Epo) induce the expressions of c-myc and c-fos proto-oncogenes in normal human erythroid progenitors.

We investigated serial expressions of eight proto-oncogenes during in-vitro differentiation of normal human burst-forming unit, erythroid (BFU-E), and found that c-myc and c-fos are expressed in progenies of BFU-E. The expressions of the two proto-oncogenes correlated to the replating efficiency and adversely to erythroid differentiation. The absence of hematopoietic growth factors decreased the expressions, but the addition of erythropoietin together with burst promoting activity induced a re-expression of the c-myc and c-fos after 2 h of incubation. These observations suggest that the c-myc and c-fos proto-oncogenes have a physiological role in the proliferation of erythroid progenitors and that activations of the two proto-oncogenes are early cellular events after the stimulation by hematopoietic growth factors.

Molecular heterogeneity of β-thalassaemia in the Japanese: identification of two novel mutations

Five unrelated Japanese β‐thalassaemia genes, from one homozygote and four heterozygotes, have been systematically characterized using DNA polymorphism analysis, polymerase chain reaction, dot‐blot hybridization and direct sequencing of amplified genomic DNA. Four different molecular defects were observed on three different β‐globin gene frameworks. One of these, the A→G mutation in the TATA box, a previously described mutation, was detected by dot‐blot hybridization in one homozygote and one heterozygote with the β‐globin gene of framework 2. The second mutation is a C→T substitution at position 654 of IVS‐2, the mutation commonly found in Chinese, which was associated with the framework 1 gene. Another two mutations, both associated with framework 3 genes, are novel ones; an amber mutation in codon 90 (GAG to TAG) and a frameshift (+G) insertion in codon 54, both of which cause a β0‐thalassaemia phenotype by premature termination of the β‐globin chain synthesis.

Expression of EVI1 and the Retinoblastoma genes in acute myelogenous leukemia with t(3;13)(q26;q13-14).

The EVI1 DNA‐binding protein gene on chromosome 3q26 has been reported to be activated in some leukemia cells with alterations in 3q26. We present an acute myelogenous leukemia (AML) patient with a rare chromosomal translocation, t(3;13)(q26.2;q13–14). By reverse transcription‐ polymerase chain reaction, we detected active transcription of the EVI1 gene in the patients leukemia cells. The retinoblastoma susceptibility (Rb) gene, a tumor‐suppressor gene, is located at chromosome 13q14 and is within the other translocation breakpoint in this patient. The expression of the Rb gene product was found to be substantially decreased in the patients leukemia cells by Western blotting. Southern blot analysis, however, revealed no gross abnormalities of the Rb gene. Although it is unlikely that the Rb gene is directly involved in this translocation, the loss of the Rb gene product combined with the activation of the EVI1 gene may have led to the development of leukemia.

Serial Studies of Bone Marrow-Derived Fibroblastoid Colony-Forming Cells and Granulocyte/Macrophage Precursor Cells in Patients with Acute Leukemia

Bone marrow-derived fibroblastoid colony-forming cells (CFU-F) and granulocyte/macrophage precursor cells (CFU-GM) were studied in patients with acute leukemia. The numbers of CFU-F and CFU-GM were significantly lower in patients with acute myelogenous leukemia (AML) and acute lymphocytic leukemia (ALL) at diagnosis than in normal subjects, although patients with AML had a very wide range of CFU-F colony-forming efficiency. However, a suppressive effect of leukemic cells on normal CFU-F colony formation was not observed. CFU-F and CFU-GM in patients with acute leukemia recovered to normal levels when complete remission (CR) was achieved and decreased again at relapse. Serial studies showed that the increase in CFU-F preceded the recovery of CFU-GM. In AML, furthermore, patients who achieved CR had a higher number of CFU-F than patients without CR, suggesting that the CFU-F level at diagnosis may contribute to the prediction of the likelihood of remission induction in patients with AML.

T-stem cell leukemia/lymphoma with both myeloid lineage conversion and T-specific δ recombination

We evaluated retrospectively the clinical and biological characteristics of six patients with CD7+ early T-acute lymphoblastic leukemia and lymphoma (T-ALL/LBL) originating from prothymocyte stage I (pro-T I) or II cells. Patients exhibited mediastinal mass (five of six) and lymphoadenopathy (five of six) but without leukocytosis and circulating blast cells (six of six). All patients achieved a complete remission. All but one had a relapse with a transformation to the mixed type (triphenotype--three cases, biphenotype-two cases) including myeloid features in three patients. The altered phenotypes were myeloperoxidase (MPO)+ (three of five), CD13+ (four of five), CD33+ (three of five) and CD19+ (three of five). The difference for MPO-positivity were observed between the bone marrow (BM)- and lymph node (LN)-blast cells (three of three). On cytogenetic analysis, there is no common abnormality in these patients. Immunomolecular analysis revealed T-cell lineage specific delta gene rearrangements [D delta 2-J delta 1 (five of six) and V delta 1-J delta 1 (one of six)] in all cases. Furthermore, D delta 2-J delta 1 occurred even in the cases with the pro-T I phenotype. Rearrangements of TCR beta, gamma or immunoglobulin heavy chain genes occurred in three patients. The same rearranged band(s) appeared at both diagnosis and relapse, indicating the same originality of the pro-T leukemic cell clone (three of three). We suggest that this type of CD7+ early T-ALL/LBL was transformed from a pro-T I or II cell, such as T-stem cell leukemia/lymphoma, which is a subtype of CD7+ stem cell leukemia as defined by Kurtzberg et al. This study reveals that pro-T I and II cells might be capable of myeloid, T- and B-lymphoid differentiation, and T-cell lineage specific TCR delta recombination occurs.

CD7+ stem cell leukemia/lymphoma. Features of a subgroup without circulating blast cells.

Recent advances in immunology have clarified the cellular origin of hematopoietic neoplasms. Blast cells with a CD7+ CD4‐ CD8‐ phenotype are demonstrated to originate from malignant pluripotent hematopoietic stem cells. In this article, the authors describe three rare cases, designated as a lymphoma type of CD7+ stem cell leukemia/lymphoma, with clinical features described below. All three patients were admitted with non‐Hodgkin lymphoma with a 2‐month to 4‐month history of lymphadenopathy. Histologic examination of lymph nodes showed lymphoblastic lymphoma (LBL) in all patients. Bone marrow blast cells had an immunophenotype consistent with CD7+ CD4‐ CD8‐ acute leukemia, although abnormal cells were not observed in the peripheral blood during the course of the disease. One patient had a recurrence in the bone marrow, with myeloperoxidase‐positive blast cells expressing myeloid differentiation antigens. Chromosomal analysis detected a common abnormal karyotype initially and at relapse. Furthermore, the same T‐cell receptor gene rearrangement was found initially and at relapse, suggesting that these blast cells originated from the same pluripotent leukemic clone. Additional studies on more patients are required to determine the clinical significance of this group, including the difference from CD7+ stem cell leukemia/lymphoma with circulating blast cells (leukemic type) or LBL. Cancer 1993; 72:99–104.

Acute Leukemias Expressing p210-and p190-Type bcr/ abl mRNAs: Report of Two Cases and Review of the Literature

We report two patients with acute leukemias who expressed two types of bcr/abl mRNA. The first case was an 8-year-old boy with acute mixed leukemia in whom the Ph1 chromosome and p210/p190 types of bcr/abl mRNAs were detected at diagnosis. The second case was a 39-year-old male with acute nonlymphocytic leukemia transformed from myelodysplastic syndrome (refractory anemia with excess of blasts). In the latter case, the p210-type mRNA appeared after leukemic transformation, and the p190-type transcript was detected only during the late stage when the Ph1 chromosome was first observed. The leukemias in these two patients were aggressive in their clinical courses. We conclude that the dual expression of p210 and p190 types of bcr/abl is a factor indicating a poor prognosis, and that, in some patients, p190-type bcr/abl may contribute to disease progression.

Missing Y Chromosome in Ph1-Negative Chronic Myeloid Leukemia with bcr Rearrangement

In a case of Philadelphia chromosome (Ph1)-negative chronic myeloid leukemia (CML) without the Y chromosome, we investigated the differences, at the molecular level, from Ph1-positive CML. Using Southern blot analysis and in situ hybridization studies, we could demonstrate a rearrangement within the breakpoint cluster region (bcr), and the location of a bcr-abl fusion gene on chromosome 22. To our knowledge, this is the first case of Ph1-negative CML with a loss of the Y chromosome in which the molecular abnormalities are shown to be identical with those in Ph1-positive CML.