Translocation (3;21) in Philadelphia chromosome-positive chronic myelogenous leukemia prior to the onset of blast crisis

Two female patients in the chronic phase of CML were found to have, in addition to t(9;22), a new karyotypic abnormality--t(3;21)(q26;q22)--present in bone marrow cells. At diagnosis, this abnormality was observed in a small number of marrow cells in both patients, and as the disease progressed in patient 1, the percentage of cells showing t(3;21) was increased, reaching 100% as the transformation to blast crisis occurred. These observations suggest that t(3;21) may represent a new and rare nonrandom rearrangement which may be identified prior to the onset of blast crisis.     

Extramedullary presentation of the blast crisis of chronic myelogenous leukaemia

We report the clinical histories and a multiparameter pathological study of the extramedullary lesions of seven patients with chronic myelogenous leukaemia in whom the initial clinical presentation of blast crisis (BC) was in an extramedullary site (lymph nodes in six, mandibular mass in one). Bone marrow BC was demonstrated simultaneously or within a few months in four patients. Three patients received chemotherapy only, four underwent bone marrow transplant. Six patients died within 1 year from diagnosis of extramedullary BC, one is alive without disease. The longest survivals (12+, 12, 11 months) were those of patients who never developed bone marrow BC and were recipients of bone marrow transplant. Studies of extramedullary disease included: histology; histochemistry for chloracetate esterase (CAE) and lysozyme; assays for TdT; electron microscopy; immunofluorescence for Fc-receptors, immunoglobulins and lymphoid and myeloid antigens by a panel of monoclonal antibodies; and cytogenetics. Three cases were classified as myeloid BC based on histochemistry and/or ultrastructure and immunology (OKM1+, MCS2+, IG10+); two as lymphoid BC (CAE-, lysozyme-, TdT+), one of them expressing a T-cell phenotype. Cytogenetic analysis of extramedullary lesions and simultaneous or subsequent bone marrows demonstrated identical karyotypes in three patients and significantly different karyotypes in one.     

Imatinib mesylate (STI571) therapy for Philadelphia chromosome-positive chronic myelogenous leukemia in blast phase

Molecular abnormalities caused by the hybrid Bcr-Abl gene are causally associated with the development and progression of Philadelphia chromosome-positive (Ph(+)) chronic myelogenous leukemia (CML). Imatinib mesylate (STI571), a specific Bcr-Abl tyrosine-kinase signal-transduction inhibitor, has shown encouraging activity in phase I and II studies of CML. Here, we describe the use of imatinib mesylate to treat 75 patients in blast-phase CML (median age, 53 years; 65 with nonlymphoid and 10 with lymphoid blasts), and compare the results with those of a historical control group treated with standard cytarabine-based therapy. Imatinib mesylate was given as oral doses at 300 to 1000 mg per day and was the first salvage therapy for 47 patients. The objective response rate was 52% (39 of 75 patients: 16 had complete and 3 had partial hematologic response; 12 had hematologic improvement; 7 returned to second chronic phase; and 1 had a complete response in extramedullary blastic disease). Response rates were not different between nonlymphoid and lymphoid groups. The cytogenetic response rate was 16% (12 patients: 5 complete, 3 partial [Ph(+) below 35%], and 4 minor [Ph(+), 34% to 90%]). The estimated median overall survival was 6.5 months; the estimated 1-year survival was 22%. Response to therapy (landmark analysis at 8 weeks) was associated with survival prolongation. Compared with standard cytarabine combinations, imatinib mesylate therapy was less toxic and produced a higher response rate (55% versus 29%, P =.001), longer median survival (7 versus 4 months, P =.04), and lower 4-week induction mortality (4% versus 15%, P =.07). Imatinib mesylate is currently being tested in combination with other drugs to improve the prognosis for blast-phase CML.     

Immunophenotypic, genomic and clinical characteristics of blast crisis of chronic myelogenous leukaemia

We have studied phenotypic and clinical features in a consecutive series of 45 patients with chronic myelogenous leukaemia (CML) in blast crisis (BC). In addition, in 22 of these patients we have analysed the genotypic characteristics including immunoglobulin, T-cell receptor (TCR) and major breakpoint cluster region (M-bcr) gene organization. The granulomonocytic and megakaryoblastic lineages are the most commonly involved in these BC of CML (33% and 33% of cases, respectively); only 18% of our cases displayed a lymphoid phenotype. Moreover, both morphological and immunophenotypic studies revealed the frequent coexistence of two or three cell populations, especially when the megakaryoblast component is involved. The lymphoid BC displayed the highest incidence of complete remissions although this was not associated with a longer survival. Only minor differences between the different myeloid subgroups were observed. Immunoglobulin heavy chain (IgH) gene rearrangement was found in five of the six lymphoid BC and in one myeloid BC. Only one case showed k light chain gene rearrangement. In all but one myeloid BC the TCR-beta gene was in germline configuration. The TCR-gamma gene was rearranged in all lymphoid and one myeloid BC, while TCR-delta gene rearrangement was detected in 67% and 16% of the lymphoid and myeloid BC, respectively. Most of the lymphoid BC (4/5) had the M-bcr breakpoint in subregion 3, while the myeloid BC had the breakpoint either in subregion 2 or 3. No differences between the different myeloid phenotypic subgroups were observed in relation to breakpoint.     

Erythroid blast crisis in chronic myelogenous leukemia

Blood or bone marrow specimens from 22 patients with chronic myelogenous leukemia in blast crisis were studied for the surface expression of glycophorin-A, a marker for early erythroid differentiation. The leukemic blasts were stained with rabbit anti- glycophorin-A antiserum. The glycophorin-A molecules detected by the rabbit antiserum were identified by polyacrylamide slab gel electrophoresis of the immunoprecipitates from the membrane lysates of surface-labeled blasts. Blasts expressing surface glycophorin-A were found in 9 of the 22 patients. In 4 patients, almost all blasts were glycophorin-A positive, and in 5 patients, less than half of the blast population expressed glycophorin-A. The present study shows that when glycophorin-A is used as a marker for erythroid blasts, involvement of the erythroid lineage during blast crisis of chronic myelogenous leukemia seems to occur more frequently than previously recognized.     

A spontaneous remission of lymphoid blast crisis in chronic myelogenous leukaemia following blood transfusion and infection

Summary. We report a case of spontaneous remission of lymphoid blast crisis in chronic myelogenous leukaemia (CML) which returned to chronic phase, without the use of cytostatic chemotherapy. following an episode of viral infection and blood transfusion. Although complete remissions of acute leukaemia have been described, this evolution is extremely rare and has never been reported in CML blast crisis. The role of hypothetical factors leading to such a rare event are briefly discussed.     

Simultaneous establishment of myeloid and B-lymphoid cell lines with identical chromosome abnormalities from Philadelphia chromosome-positive chronic myelogenous leukaemia

Two continuously growing cell lines, designated YOS-M and YOS-B, were established simultaneously from a patient with Philadelphia (Ph1) chromosome-positive chronic myelogenous leukaemia (CML) in myeloid blast crisis. Both YOS-M and YOS-B had the Ph1 chromosome and identical additional chromosome abnormalities, which were not detected in the chronic phase. Cytochemical analysis showed that YOS-M was significantly positive for peroxidase, whereas YOS-B was entirely negative. YOS-M expressed myeloid-associated antigens (CD14, CD33) as well as CD4, CD25 and CD34. The surface phenotype of YOS-M was identical to that of the leukaemic blasts found in the patient. On the other hand, YOS-B expressed mature B-cell markers, CD19, CD20, CD21 and surface immunoglobulin, but not myeloid-associated antigens. These two cell lines showed an identical rearrangement pattern of the break point cluster region on chromosome 22, but rearrangement of the immunoglobulin heavy chain gene was detected only in YOS-B. These findings provide definite evidence that CML cells still have the capability to differentiate and mature along different haematopoietic cell lineages even after blast crisis.     

Chronic myelogenous leukemia in blast crisis: retrospective analysis of prognostic factors in 90 patients

 Ninety patients with Philadelphia chromosome-positive chronic myelogenous leukemia in blast crisis were reviewed to identify significant prognostic associations. At diagnosis of blast crisis the main clinical, laboratory, and cytogenetic data were recorded and evaluated for prognostic significance. At the time of the analysis 89 patients had died, with a median survival of 11 weeks from diagnosis of blast crisis. Patient characteristics demonstrated in the univariate analysis to have significant association with shorter survival were: thrombocythemia, leukocyte count above 20×10⁹, Karnofsky index <50%, nonlymphoid blast cell morphology, cytogenetic clonal evolution, the presence of a double Philadelphia chromosome or trisomy 8, and no response to therapy. In 17 of 59 patients (29%) evaluable for response to therapy a complete or partial remission was achieved. These responders had a significantly longer median survival (25 weeks) as compared with nonresponders (9 weeks). Response to therapy was significantly better in lymphoid blast crisis and in patients without clonal evolution. In a multivariate analysis containing all significant variables of the univariate analysis two parameters retained their prognostic significance: response to therapy and trisomy 8. In spite of the short overall survival in blast crisis, the determination of prognostic factors may be a useful tool for the clinician planning therapy, especially new therapeutic approaches. Received: 14 November 1995 / Accepted: 20 August 1996     

Expression of the multidrug transporter, P-glycoprotein, in chronic myelogenous leukaemia cells in blast crisis

The overexpression of a cell-surface glycoprotein termed P-glycoprotein (P-gp) is frequently associated with multidrug resistance (MDR) in cell lines in vitro. To evaluate the implications of P-gp expression in clinical drug-resistance, we examined the expression of P-gp in fresh leukaemia cells from chronic myelogenous leukaemia (CML) patients in blast crisis. By using immunoblotting with a monoclonal antibody against P-gp, C219, we showed that leukaemia cells from three CML patients in blast crisis were P-gp negative at the stage when these patients were in complete remission, and that the cells showed high levels of P-gp expression at times when the same patients had relapsed and had not responded to chemotherapy. Six out of 11 patients (nine in the refractory state) were P-gp positive and they rarely responded to chemotherapy. These data suggest that the expression of P-gp is closely associated with drug-resistance in CML.     

Extramedullary presentation of blast crisis in chronic myelogenous leukemia

We present a case with the clinical and pathological impression of Ph1-positive chronic myelogenous leukemia in extramedullary blast crisis involving lymph nodes as demonstrated by morphological and cytogenetic studies. The hyperploid cell lines that were present in the lymph node were not present in the bone marrow. The present case demonstrates that cytogenetic and morphological studies of extramedullary organs are helpful in the confirmation of the diagnosis of blast crisis, especially when lymph nodes are the site of original presentation.     

Blast crisis of Philadelphia chromosome-positive chronic myelocytic leukemia (CML)

Summary We have studied the clinical courses of 69 patients with blastic crises of Philadelphia chromosome positive CML to identify parameters that were associated with an increased response rate or survival. Cytogenetic analysis at the time of blastic transformation revealed additional chromosome changes in 70% of the patients tested. Bone marrow fibrosis was detected in 58% of evaluable patients. Lymphoblastic transformation was seen in 28% of the patients tested with cell surface marker analysis. The value of 5'-nucleotidase as a marker for distinguishing lymphoid from non-lymphoid blast crisis was confirmed. Of 57 evaluable patients, 23 (40%) responded to therapy (CR/PR longer than 14 days). Median survival was 75 days. Longer survival was related to the following factors: Ph¹-chromosome as the only detectable cytogenetic abnormality; lymphoblastic transformation; no bone marrow fibrosis; high percentage of blasts and promyelocytes in the bone marrow, and response to therapy. No prognostic significance was associated with age, sex, Tdt, LDH, spleen size, duration of the chronic phase of the disease, white blood cell count, Hb, platelet count and percentages of basophils, eosinophils, erythroblasts and blasts and promyelocytes in the peripheral blood. These data confirm the poor prognosis of patients with blastic crisis of CML treated by conventional chemotherapy.     

Philadelphia chromosome-negative chronic myelogenous leukaemia: a morphological reassessment

Morphological re-examination of 25 cases classified as Ph1-negative chronic myelogenous leukaemia (CML), with particular attention to the recent French-American-British (FAB) group proposals for the diagnosis of the myelodysplastic syndromes, led to reclassification of all but one of these cases. Upon review of pretreatment material, seven of the 25 cases (28%) were considered to represent myeloproliferative and reactive conditions other than CML. Of the remaining 18 cases, 17 (94%) were reclassified as myelodysplastic syndromes (MDS). These included one case of refractory anaemia (RA), three of refractory anaemia with excess of blasts (RAEB), four of RAEB in transformation (RAEBT), and nine of chronic myelomonocytic leukaemia (CMMoL). Haematological findings in these 17 patients were compared to those in 50 randomly selected patients with Ph1-positive CML. Whereas an absolute basophilia in the peripheral blood was a nearly constant feature in the Ph1-positive group, it was lacking in all but one of the patients with myelodysplastic syndromes. Differences in the pattern and degree of dysplasia were also noted. Only one of the 25 cases studied was considered morphologically and clinically indistinguishable from Ph1-positive CML. It appears that Ph1-negative CML constitutes a heterogeneous group of prognostically distinct disorders and that, in most instances, careful morphologic examination will permit precise classification.     

Secondary T-acute lymphoblastic leukaemia mimicking blast crisis in chronic myeloid leukaemia

A 34-year-old man with chronic myeloid leukaemia (CML) firstly developed a lymphoid blast crisis of B-cell type. After a second chronic phase which lasted for > 4 years with maintenance chemotherapy of hydroxyurea, 6-mercaptopurine and methotrexate, he developed a T-cell acute lymphoblastic leukaemia of TcR-gammadelta+ type. Cytogenetic analysis revealed disappearance of the t(9;22) translocation and appearance of new abnormalities consistent with the diagnosis secondary acute leukaemia. To our knowledge, secondary leukaemia in CML has not previously been reported.     

New type of Bcr/Abl junction in Philadelphia chromosome-positive chronic myelogenous leukemia

A new and rare type of Bcr/Abl junction between exon C3 of the 3' portion of the Bcr gene and Abl exon 2 has been identified in the leukemic cells of two Ph1-positive chronic myelogenous leukemia patients in chronic phase. This is the fourth type of Bcr/Abl junction so far identified in Ph1-positive hematologic malignancies and is a consequence of an unusual breakpoint position on chromosome 22 that falls approximately 20 kb downstream of the major breakpoint cluster region (bcr) of the Bcr gene. The new hybrid mRNA is 540 base pairs (bp) longer than that expressed by the K562 cell line and could codify for a Bcr/Abl protein carrying 180 additional aminoacids with respect to the larger P210 protein so far identified. The hematologic phenotype expressed by the two patients carrying this unusual type of Bcr/Abl rearrangement does not significantly differ from that commonly seen in chronic myelogenous leukemia.     

Natural killer lymphocyte blast crisis of chronic myelogenous leukemia

We describe for the first time a case report documenting a chronic myelogenous leukemia (CML) patient who developed a blast crisis of natural killer (NK) lymphocytes. Many of the blasts exhibited large granular lymphocytic (LGL) morphology. Single parameter immunophenotyping results determined that the granulated as well as the agranulated blast cells were NK lymphocytes (CD45, NKH1, CD2, LEU 17, and CD16 positive; CD3, CD8, and LEU 7 negative). Dual parameter flow cytometric testing also determined that some of the blasts expressed the CD11b and CD11c markers as reported for some types of NK lymphocytes. Approximately 10% of the cells were in the S phase of the cell cycle as determined by a modified Vindelov DNA content analysis test and may theoretically reflect some of those cells expressing CD11b and CD11c. The cells did not express in vitro NK lymphocyte functional activity against a K562 target and therefore similar to other reported cases of presumably immature NK lymphocytic leukemias. The NK lymphocyte blast crisis was successfully treated with vincristine and prednisone. The patient's disease eventually relapsed and transformed to a progenitor stem cell before she died (CD45, 13, CD38, and CD34 positive). The flow cytometric immunophenotyping results contributed significantly as an important adjunct in determining the appropriate diagnosis, helping to select the type of therapy, and monitoring the patient with this unusual type of blast crisis.     

Interferon-alpha produces sustained cytogenetic responses in chronic myelogenous leukemia. Philadelphia chromosome-positive patients

OBJECTIVES: To evaluate the frequency and the course of complete cytogenetic responses in interferon-alpha (IFN-alpha)-treated patients with chronic myelogenous leukemia. DESIGN: Two prospective trials in consecutive patients. SETTING: A major tertiary cancer center. PATIENTS: Ninety-six consecutive patients with chronic myelogenous leukemia with disease duration of less than 1 year. INTERVENTION: Patients received partially pure IFN-alpha intramuscularly, from 3 to 9 million U/d (51 patients) or recombinant IFN-alpha 2a (Roferon, Hoffmann-LaRoche, Inc., Nutley, New Jersey), 5 million U/m2 body surface area daily (45 patients). MEASUREMENTS: Hematologic and cytogenetic tests were administered. MAIN RESULTS: Seventy of the patients (73%) achieved hematologic remission (95% CI, 63% to 81%), and 18 (19%) had complete suppression of the Philadelphia chromosome on at least one cytogenetic test. A complete cytogenetic response was induced in 7 of 51 or 14% (CI, 6% to 26%) of the patients treated with the partially pure IFN-alpha and in 11 of 45 or 24% (CI, 13% to 40%) of the patients treated with recombinant IFN-alpha 2a. The difference in complete cytogenetic response between the two groups was 10.7% (CI, - 5% to 26%; P greater than 0.2). Eleven patients had durable, ongoing, complete cytogenetic responses from 6 to more than 45 months (median, more than 30 months). CONCLUSION: This study was the first to show sustained, complete cytogenetic responses in a subset of patients with chronic myelogenous leukemia treated with single-agent therapy. The nature of this remission, that is, whether it depends on continuous therapy, requires further study.     

Double Philadelphia masquerading as chromosome 20q deletion--a new recurrent abnormality in chronic myeloid leukaemia blast crisis

Summary. The most common abnormality of chromosome 20 in haematological malignancy is deletion of the long arm [del(20q)]. These interstitial deletions are variable in size and are seen in both premalignant haematological conditions and acute myeloid neoplasia. A commonly deleted region (CDR), mapped within the 20q11.2/q13.1 segment with an estimated size of 1·7 Mbp, is considered to present a primary genetic lesion marking a gene(s), the loss of which is responsible for the pathogenesis of these haematological disorders. While a small number of recurrent translocations involving chromosome 20 have also been reported, no recurrent aberration of this chromosome has been associated with myeloid disease progression. We present nine cases of Philadelphia (Ph)-positive chronic myeloid leukaemia (CML) in which deletions of chromosome 20 were also detected by conventional karyotyping. In six cases, fluorescent in situ hybridization (FISH) mapping confirmed a del(20q) which corresponded to the myeloid CDR. In the remaining three cases however, the presumed del(20q) marker was shown to be the result of an unbalanced translocation between band 20p11 and a second copy of the Ph chromosome. This new abnormality, termed dic(20;Ph) for short, was identical to a del(20)q by G-banding, and combined duplication of the breakpoint cluster region and Abelson murine leukaemia viral oncogene homologue (BCR-ABL) fusion with loss of the 20p11-pter segment. In all three cases, the dic(20;Ph) was associated with disease progression and therefore represents a new recurrent abnormality in CML blast crisis.