C. R. Bartram

Detection of chimeric BCR-ABL genes in acute lymphoblastic leukaemia by the polymerase chain reaction

Philadelphia chromosome-positive acute lymphoblastic leukaemia (ALL) is most common in adults and is associated with poor prognosis. Since karyotypic identification of the Philadelphia translocation has been hampered by technical difficulties, we used the polymerase chain reaction (PCR) to look for the BCR-ABL rearrangement in stored samples from a selected group of 314 German ALL patients. BCR-ABL transcripts were found in 77 of 179 adults and were restricted to those with B-precursor leukaemias. 55% of adult common ALL patients had BCR-ABL and its presence correlated with poor overall survival and remission duration. Of 135 children with common ALL, 5 (6%) primary cases and 8 (17%) with recurrent neoplasias were PCR-positive. We recommend prospective evaluation of BCR-ABL analysis with PCR in patients with a B-precursor leukaemia.

Polymerase chain reaction for detection of residual leukaemia.

The occasional finding of cells positive for the Philadelphia (Ph) chromosome months or years after bone-marrow transplantation for chronic myeloid leukaemia raises the possibility that the Ph-positive clone may never be eradicated. The polymerase chain reaction with probes able to detect the transcript of the bcr/abl hybrid gene at very low levels was used to study marrow cells from seven patients in continuing haematological and cytogenetic remission 5-7 years after allogeneic bone-marrow transplantation for chronic myeloid leukaemia. No evidence of the leukaemic mRNA was found. Thus, it seems that all leukaemic cells were eradicated in these patients and that they are truly cured.

Incidence and Prognostic Significance of Immunophenotypic Subgroups in Childhood Acute Lymphoblastic Leukemia: Experience of the BFM Study 86

Due to the increasing availability of monoclonal antibodies (MAbs) recognizing lymphoid-, myeloid-, and progenitor-cell-associated antigens, immunophenotyping has greatly influenced studies on the biologic features of normal and leukemic hematopoietic progenitor cells (Greaves 1986). It has become possible to demonstrate the practical value of these data for the precise diagnosis and definition of clinically relevant immunophenotypic subsets of acute lymphoblastic leukemia (ALL) (Janossy et al. 1989). More recently, immunophenotyping has been supplemented by cytogenetic and molecular-genetic analyses in order to better characterize the biologic heterogeneity of ALL and to elucidate the mechanisms of lymphoid cell transformation and aberrant regulation of leukemic cell growth (Look 1988; Bain and Catovsky 1990; Pui et al. 1990c; van Dongen and Wolvers-Tettero 1991).

Incidence of ras gene mutations in neuroblastoma

Using a rapid dot-blot screening procedure based on DNA amplification and hybridization to synthetic oligonucleotide probes, we investigated 18 neuroblastomas in various clinical stages for the presence of ras mutations. In none of the samples was a mutation in the relevant codons 12, 13 or 61 of Ha-ras, Ki-ras or N-ras found. These data virtually exclude the participation of mutated ras genes in the genesis of neuroblastoma.

Clinical Significance of Cytogenetic Studies in Childhood Acute Lymphoblastic Leukemia: Experience of the BFM Trials

During the past few years the number of cytogenetic analyses carried out on bone marrow and blood samples from children with acute lymphoblastic leukemia (ALL) has gradually increased, and as the number of patients found to have chromosomal aberrations in their leukemic cells rose, the clinical importance of these abnormalities became clearer. There is no doubt about the specificity of several chromosomal changes, e.g., t(8;14) in B-cell malignancies (Kaneko et al. 1980; Berger et al. 1985) or the translocations involving the band 14qll (Williams et al. 1984; Harbott et al. 1986; Lampert et al. 1988), which can be helpful in leukemia diagnosis. The prognostic meaning of these typical aberrations, however, is not yet clear. Although most authors describe the chromosomal aberrations as an independent prognostic factor (Kaneko et al. 1981; Morse et al. 1983; Bloomfield et al. 1986; Williams et al. 1986; Yunis et al. 1986; Seeker-Walker 1990), it has become evident during the last few years that their prognostic importance may be overcome by appropriate therapy (Fletcher et al. 1989; Seeker- Walker 1990; Raimondi et al. 1990).

Clonal variation in childhood acute lymphoblastic leukaemia at early and late relapse detected by analyses of phenotype and genotype.

To increase our knowledge of the clonal relationship of leukaemia relapse, the genotypes and phenotypes of ten children with acute lymphoblastic leukaemia (ALL) were examined at initial diagnosis and relapse. Seven patients were phenotyped as common ALL, two as mixed, and one as T-cell ALL (T-ALL). Comparative analyses of immunoglobulin (Ig) heavy and light chain as well as T-cell receptor β-chain (Tβ) sequences revealed clonal variations, i.e. appearance of a novel or an evoluted leukaemic cell clone in five patients coinciding with the loss of common acute lymphoblastic leukaemic antigen (CALLA) in four cases, irrespective of early or late relapse. Conversion of early B- to T-ALL or lymphoblastic to non-lymphoblastic leukaemia was not noted in any of the patients examined. Our results suggest that clonal variation is a frequent event in childhood ALL.

Molecular genetic techniques for detection of minimal residual disease in acute lymphoblastic leukemia: possibilities and limitations.

Despite impressive advances in the treatment of acute lymphoblastic leukemia (ALL), disease relapse following successful remission induction still poses a significant clinical problem (Champlin and Gale 1989). Since most recurrences originate from neoplastic cells escaping the therapeutic intervention, the development of methods to monitor individual responses of patients, to detect impending relapses prior to clinical manifestation, or to determine the quality of a bone marrow scheduled for autologous trans-plantation represents a major challenge of today’s oncology.

Acute promyelocytic leukaemia with hypogranular bone marrow blasts in a 16-year-old girl: Diagnostic value of different genetic methods

We report a 16-year-old girl who presented with anaemia, thrombocytopenia, leukocytosis and disseminated intravascular coagulation. Bone marrow analysis showed promyelocyte-like myeloblasts with rare Auer rods and very few granula. CD2 antigen was not expressed in bone marrow blasts. Karyotype analysis revealed a complex pattern of chromosomal aberrations without the promyelocytic leukaemia (PML) specific translocation t(15;17) (q22;q21). Southern blot analysis revealed a rearrangement of the retinoic acid receptor alpha (RARα) locus. Reverse transcribed polymerase chain reaction assay confirmed the initial diagnosis of PML by amplification of the PML-specific PML/RARα fusion transcript.ConclusionThis case report confirms that a characteristic translocation t(15;17) is not always detectable in PML blasts by karyotype analysis despite presence of specific PML/RARα-transcripts. Together with careful morphological analysis of bone marrow blasts this assay apparently is the most specific and sensitive method to confirm the diagnosis.

Clinical Relevance of Chromosomal Aberrations in Childhood ALL: Cytogenetic Data of the German Therapy Studies

By the increasing number of analyses in the field of tumor cytogenetics the high specificity of chromosomal abnormalities in all kinds of neoplasia have become more and more obvious. Aberrations involving band q11 of chromosome 14 are, for example, typical for T cell ALL (Williams et al. 1984; Harbott et al. 1986; Lampert et al. 1988), and t(8; 14) was only found in B cell malignancies (Kaneko et al. 1980; Berger et al. 1985).

Immunoglobulin and T-Cell Receptor Gene Rearrangements in Human Acute Leukemias

Development of immunological methods has made it possible to examine the cellular origin of leukemia cells in relation to their normal counterparts and acute lymphoblastic leukemia (ALL) is generally classified into the following major subgroups: T-ALL, B-ALL and common ALL (cALL) (1). Not infrequently, however, it is impossible to classify acute leukemias as B or T cell or nonlymphoid in origin despite examining lineage associated surface markers, as some malignancies represent stages of differentiation prior to the expression of lineage restricted surface markers. These limitations can now be overcome by utilizing the DNA rearrangement of immunoglobulin (Ig) and T cell receptor genes to reveal the clonality, cellular lineage, and stage of differentiation of such acute undifferentiated leukemias (AUL) (2).