ABSTRACT
Genomic DNA from 106 cases of adult de novo acute myeloid leukaemia (AML) was screened by polymerase chain reaction (PCR) and gel electrophoresis for FLT3 internal tandem duplication (ITD) mutations within the juxtamembrane (JM) domain. FLT3 mutations were detected in 14 cases (13.2%) and occurred in FAB types M1 (4 out of 14 cases), M3 (1 out of 10 cases), M4 (5 out of 37 cases) and M5 (4 out of 11 cases). Sequence analysis of four cases with abnormal PCR electrophoretic patterns revealed in frame duplications in the region of exon 11 of between 27 and 111 base pairs. Three are predicted to result in the tandem duplication of adjacent amino acid residues and one to result in a tandem duplication plus insertion of a novel amino acid motif. Statistical analysis showed the FLT3 mutations to be a strong prognostic factor, with patients lacking the mutation surviving significantly longer from diagnosis (mean 29.1 months) than those with an ITD (mean 12.8 months; P = 0.0002). Thirteen of the 14 patients with FLT3 mutations died within 18 months of diagnosis. FLT3 mutations were of prognostic significance in good risk disease (P = 0.04), as well as in patients with standard risk disease (P = 0.0096). This study demonstrates that the FLT3 ITD mutation occurs in a significant percentage of adult AML cases and is an important adverse prognostic factor that appears independent of conventional karyotypic findings.
Subject(s)
Leukemia, Myeloid/genetics , Proto-Oncogene Proteins/genetics , Receptor Protein-Tyrosine Kinases/genetics , Acute Disease , Adolescent , Adult , Aged , Amino Acid Sequence , Electrophoresis, Polyacrylamide Gel , Female , Humans , Leukemia, Myeloid/mortality , Male , Molecular Sequence Data , Mutation , Prognosis , Survival Analysis , Tandem Repeat Sequences , fms-Like Tyrosine Kinase 3ABSTRACT
The rearrangements t(8;21)(q22;22) and inv(16)(p13q22) are two of the most frequently seen in acute myeloid leukaemia (AML), accounting for 8% and 4% of cases respectively. Detection of these abnormalities is important for disease management as both are associated with good responses to conventional chemotherapy and prolonged disease-free survival. Recent reports using reverse transcriptase polymerase chain reaction (RT-PCR) suggest that significant proportions of AML cases without a visible t(8;21) or inv(16) show expression of an abnormal fusion gene transcript and, consequently, they could not be detected using conventional cytogenetic analysis alone. We present here a four centre study involving 412 cases of AML screened using both standard cytogenetics and RT-PCR for AML1-ETO and CBF beta-MYH11. We detected a cytogenetic t(8;21) in 31 out of 412 (7.5%) cases and an inv(16) or t(16;16) variant in 27 out of 412 (6.6%) cases. RT-PCR detected only two cases (0.5%) of cryptic t(8;21) and no instances of cryptic inv(16). Both cryptic t(8;21) cases had the classic M2 FAB morphology for this type of disease. Our data concur with the established FAB type distribution of the rearrangements and indicate that cryptic t(8;21) and inv(16) may be much less frequent than reported elsewhere.
Subject(s)
Gene Rearrangement , Leukemia, Myeloid/genetics , Acute Disease , Adolescent , Adult , Aged , Aged, 80 and over , Child , Child, Preschool , Chromosome Inversion , Chromosome Mapping , Chromosomes, Human, Pair 16 , Chromosomes, Human, Pair 21 , Chromosomes, Human, Pair 8 , Female , Genetic Markers , Humans , Incidence , Infant , Male , Middle Aged , Prognosis , Reverse Transcriptase Polymerase Chain Reaction , Translocation, GeneticABSTRACT
We report the use of multiplex polymerase chain reaction (PCR), using 4% polyacrylamide gel electrophoresis (PAGE) for the detection of BCR-ABL transcripts in Philadelphia-positive disease. Three out of 50 cases [two out of 37 chronic myeloid leukaemia (CML), one out of 13 acute lymphoblastic leukaemia (ALL)] possessed rare breakpoints; an e19a2 and e13a3 in CML and an e1a3 in the ALL. We suggest that multiplex PCR using 4% PAGE and optimized for smaller transcript detection may lead to a higher detection rate of rare BCR-ABL breakpoints. Multiplex PCR, however, failed to distinguish e13a2 from e1a3 transcripts. Finally, the presence of e13a3 in CML supports the view that abl exon 2 sequences are unnecessary for the pathogenesis of 'classic' CML.
Subject(s)
Fusion Proteins, bcr-abl/genetics , Leukemia, Myelogenous, Chronic, BCR-ABL Positive/genetics , Precursor Cell Lymphoblastic Leukemia-Lymphoma/genetics , Chromosome Breakage , Electrophoresis, Polyacrylamide Gel , Genotype , Humans , Phenotype , Philadelphia Chromosome , Polymerase Chain Reaction/methodsABSTRACT
Hodgkin's disease and non-Hodgkin's lymphomas can be treated and, in a large number of cases, cured by first-line chemotherapy or radiotherapy. Unlike many other malignancies, relapse is not uniformly fatal but the treatment is usually markedly myelotoxic with the high doses of chemotherapy used in relapse. Haematopoietic reconstitution with either autologous marrow or peripheral stem cells postchemotherapy has made high-dose chemotherapy relatively safe with mortality rates as low as 2% in some centres. The clinical indications for high-dose therapy in lymphoma management for patients with relapsed and bad prognosis disease are reviewed. The advantages of autologous bone marrow and peripheral stem cell transplants are compared and current peripheral stem cell mobilization and harvesting practice is discussed.
