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M Talpaz

Publications and source records attributed to M Talpaz.

At least 289 records · Page 16Linked to original sources
PubMed1988

Clinical evaluation of a DNA probe assay for the Philadelphia (Ph1) translocation in chronic myelogenous leukemia.

We report the clinical evaluation of an improved DNA probe assay for the characteristic genetic marker of human CML, observed by cytogenetics and designated the Philadelphia chromosome (Ph1). The Ph1 chromosome results from the fusion of c-abl proto-oncogene sequences from chromosome 9 to phl gene sequence on chromosome 22. (The phl gene is often referred to as bcr. However, for clarity we prefer to reserve the designation "bcr" for the region within the phl gene in which translocation breakpoints have been found to occur. We also find it useful to distinguish between two such regions in phl, bcr-210 and bcr-190, named after the 210- and 190-kDa phl/abl fusion proteins resulting from translocations with breakpoints in the respective regions. We refer to the corresponding chromosomal translocations as Ph1(bcr-210) and Ph1(bcr-190).) DNA, extracted from peripheral blood (PB) or bone marrow (BM) and digested with restriction endonuclease BglII, is hybridized with a probe (phl/bcr-3) spanning a breakpoint cluster region within phl. Rearrangements are revealed by the presence of one or two novel junction fragments. Clinical specimens from leukemic patients with active disease were compared by cytogenetic and DNA probe analysis at seven centers in the United States and Europe. The probe assay identified the phl rearrangement in 190 of 191 cases of Ph1-positive CML, as well as in 12 of 27 clinically diagnosed CML specimens lacking a typical Ph1 chromosome. DNA rearrangements also were seen in two of six cases of Ph1-positive ALL. No false positive results were obtained among 93 non-leukemic controls. Mixing experiments showed that the DNA probe assay can detect as few as 1% leukemic cells in a specimen. A preliminary study of CML patients in remission after allogeneic BM transplantation revealed a small fraction of residual Ph1-positive leukemic cells in a significant number of such patients.

Blotting, Southern↗
PubMed1988

Aberrant expression of the K-ras proto-oncogene in B-cell malignancies.

The proto-oncogenes have the capacity for conversion to an oncogene that is capable of inducing or maintaining the transformed state when they are overly expressed or altered by mutation or rearrangement. To study the possible involvement of these genes in the neoplastic transformation of B-cell malignancies, we have analyzed their expression in 18 fresh samples obtained from the peripheral blood of patients with a variety of B-cell malignancies. A high-molecular weight c-k-ras transcript (5.2 kb) was detected in all samples including normal lymphocytes. In contrast, a low-molecular weight c-k-ras transcript (1.2 kb) was not detected in our control normal lymphocytes, but was found in 9 fresh samples. The 1.2 kb c-k-ras transcript was expressed 2-3-fold higher than the 5.2 kb c-k-ras transcript. C-h-ras (2.9 kb, 1.4 kb) was expressed at a low level in 4 and 13 samples, but not in normal lymphocytes. C-myc (2.3 kb) and c-raf (3.8 kb) were expressed in all samples including normal lymphocytes without significant variation in the level of expression. C-fos (2.2 kb) was expressed in 15 samples and normal lymphocytes with a wide range in the level of expression. C-myb (3.7 kb) and c-fes (2.7 kb) were expressed at a low level in 6 and 10 samples, respectively, including normal lymphocytes. C-sis (4.0 kb) was not detected in any sample including normal lymphocytes.

DNA↗
PubMed1988

Analysis of breakpoints within the bcr gene and their correlation with the clinical course of Philadelphia-positive chronic myelogenous leukemia.

Chronic myelogenous leukemia (CML) is characterized by a reciprocal translocation between chromosomes 9 and 22. The breakpoints on chromosome 22 are clustered within a 5.8-kilobase (kb) DNA fragment known as the breakpoint cluster region (bcr), which encodes part of a functionally active gene. We analyzed the bcr in DNAs from 108 consecutive, unselected Philadelphia chromosome-positive CML patients by Southern blot and determined five restriction enzyme fragments within which breaks occur on chromosome 22. The exact sublocalization was determined in the DNA of 100 patients. It was found to be within the 5.8-kb in 99 patients and outside the bcr in only one. Within the bcr, most of the breakpoints occurred in fragments 1, 2, and 3. Overall, laboratory and clinical features of CML did not correlate with specific breakpoint fragments, but chronic-phase duration was longer in patients with a breakpoint in fragment 2 of the bcr. Large 3' bcr deletions were found in nine patients but did not influence clinical outcome. DNA from one of six patients analyzed both during chronic phase and blastic crisis showed an additional aberrant fragment, which suggested that a second abnormal clone developed in blastic crisis.

Blast Crisis↗
PubMed1988

Lack of breakpoint cluster region rearrangement in marrow fibroblasts of patients with Philadelphia chromosome-positive chronic myelogenous leukemia.

Involvement of marrow fibroblasts in myeloproliferative disorders such as chronic myelogenous leukemia (CML) is controversial. We examined the blood leukocytes and bone marrow fibroblasts of four patients with Philadelphia chromosome- (Ph1) positive CML for evidence of rearrangement in the breakpoint cluster region (BCR). Fibroblasts were obtained by growing bone marrow in long-term culture, disposing of nonadherent cells, and passaging three times before final trypsinization and analysis. DNA from fibroblasts and peripheral leukocytes was digested with Bg1II, Bc1I, EcoRI, and HindIII restriction endonucleases and hybridized to both 3' and 5' BCR probes. Southern blot analysis of the DNA from the peripheral leukocytes in all four patients demonstrated rearrangement in the BCR. However, analysis of DNA from marrow fibroblasts showed only the normal BCR restriction fragments in all patients. This study demonstrates the absence of the Ph1 -associated molecular events in the fibroblasts of patients with CML. It is consistent with previous studies using G6PD isoenzymes to show polyclonality in CML fibroblasts and with most cytogenetic studies that did not show the Ph1 in these cells. In summary, we present further evidence that involvement of CML fibroblasts is a secondary event in the leukemogenic process.

Bone Marrow Cells↗
PubMed1987

Therapy of lymphoid and undifferentiated chronic myelogenous leukemia in blast crisis with continuous vincristine and adriamycin infusions plus high-dose decadron.

Thirty patients with Philadelphia chromosome-positive lymphoid (20 patients) or undifferentiated (ten patients) chronic myelogenous leukemia in blast crisis were treated with 0.4 mg of vincristine by continuous intravenous infusion (CIV) daily for 4 days; (doxorubicin) 12 mg/m2 of Adriamycin (Adria Laboratories, Columbus, OH) by continuous intravenous infusion daily for 4 days; and 40 mg of decadron daily on days 1 through 4, 9 through 12, and 17 through 20 (VAD). Course 2 was given starting on day 24 with the addition of cyclophosphamide 1 g/22. Overall nine patients achieved complete remission (30%) and three attained a partial remission (10%), for an overall response rate of 40%. Four patients expired during induction whereas 14 had resistant disease. Response rate was significantly higher for patients with lymphoid compared to undifferentiated morphology (55% versus 10%; P = 0.05). In lymphoid blast crisis, Calla-positive disease was associated with a higher response rate compared to Calla-negative disease (75% versus 25%; P = 0.08). Eleven patients developed infections, and seven had fever without documented infections. The median overall survival was 29 weeks. Median survival was 43 weeks for patients achieving complete remission and 20 weeks for those with resistant disease. Remission duration was 39 weeks. After primary and salvage therapy, nine patients are alive, six of them in continuous remission for 19+ to 112+ weeks. The authors conclude that VAD chemotherapy is an effective regimen with acceptable toxicity in patients with lymphoid blast crisis especially those with Calla-positive disease. Alternate induction regimens for undifferentiated disease and for maintenance therapy are currently being investigated.

Adult↗
PubMed1987

The relevance of reticulin stain-measured fibrosis at diagnosis in chronic myelogenous leukemia.

Although collagen myelofibrosis indicates poor prognosis in late stages of chronic myelogenous leukemia, the significance of reticulin stain-measured fibrosis in newly diagnosed patients is unknown. One hundred and thirty-eight patients with untreated or minimally treated chronic phase Philadelphia chromosome-positive chronic myelogenous leukemia had reticulin stain studies made on their bone marrows at diagnosis. Reticulin fibrosis was graded on a scale of 1 to 4. Significant (Grade 3 or 4) fibrosis was noted in 65 patients (47%). Compared with patients with mild (Grade 1 to 2) reticulin fibrosis, those with significant fibrosis had a higher incidence of splenomegaly greater than or equal to 10 cm (29% versus 49%; P = 0.02), hemoglobin less than 10 g/dl (19% versus 49%; P less than 0.01), weight loss greater than or equal to 6.75 kg (10% versus 30%; P = 0.11), marrow blasts greater than or equal to 5% (7% versus 28%; P less than 0.01), peripheral blasts greater than or equal to 3% (30% versus 46%; P = 0.09), and additional karyotypic abnormalities (1% versus 17%; P less than 0.01). The incidence of thrombocytosis was similar in the two groups. Prognostically, median survival was significantly shorter for the 26 patients with Grade 4, compared with the 39 patients with Grade 3, and the 73 patients with Grade 1 or 2 reticulin fibrosis (32 versus 49 versus 57 months; P = 0.03). Reticulin fibrosis is a useful biologic and prognostic index in newly diagnosed patients with chronic phase chronic myelogenous leukemia.

Actuarial Analysis↗
PubMed1987

Analysis of P210bcr-abl tyrosine protein kinase activity in various subtypes of Philadelphia chromosome-positive cells from chronic myelogenous leukemia patients.

An altered c-abl gene product (P210bcr-abl) possessing associated tyrosine protein kinase activity was recently been reported in several blast chronic myelogenous leukemia (CML) cell lines. We have examined different morphological types of leukocytes directly obtained from patients at the blast crisis stage of CML for expression of P210bcr-abl tyrosine protein kinase activity. Phosphorylation of P210bcr-abl in an immune complex kinase assay using an anti-v-abl peptide serum was observed in blast cells from four Philadelphia chromosome (Ph1)-positive CML patients in blast crisis. P210bcr-abl protein kinase activity was detected regardless of whether the blast cells were of myeloid, lymphoid, or undifferentiated morphology. P210bcr-abl protein kinase activity was not detected in immune complexes either from leukocytes of four Ph1-negative CML patients in blast crisis, of five acute myelogenous leukemia patients, or in the promyelocytic cell line HL-60. Mature myeloid cells are associated with an inhibitory factor for not only P210bcr-abl protein kinase activity, but also protein kinases in general. Therefore, analyses of Ph1-positive benign phase CML myeloid cells, the majority of which are well differentiated, could not be successfully performed. The inhibition of P210bcr-abl protein kinase activity is not a specific property of mature cells from CML patients since granulocytes from a normal volunteer also demonstrated a similar effect. However, extracts of Ph1-positive cultured B-lymphocytes from a patient in benign phase demonstrated active P210bcr-abl protein indicating that the P210bcr-abl protein is expressed in an enzymatically active form in the earlier phases of CML. In addition to the previously reported P210 and P190 abl-related proteins, a novel Mr 53,000 protein was found to undergo phosphorylation at serine and tyrosine in immune complex kinase assays of two blast crisis CML cell lines (K562 and EM2) and in samples from blast crisis patients in which P210bcr-abl was detected. Peptide mapping by the Cleveland technique suggested that Mr 53,000 protein is unrelated to P210bcr-abl. Immune complex kinase assays of K562 cells with an anti-src serum (GD-11) yielded active c-src kinase and a Mr 50,000 phosphorylated protein, both of which were resistant to alkaline hydrolysis. Peptide mapping suggested that Mr 53,000 protein is related to Mr 50,000 protein which is precipitated with P210bcr-abl as an Mr 300,000 protein complex.

Amino Acids↗
PubMed1987

Therapy of chronic myelogenous leukemia.

While the demonstrated antiviral, antiproliferative, and immunomodulatory properties of interferons have led to a number of theories regarding their potential use in treating individuals with chronic myelogenous leukemia (CML), their limited availability has prevented thorough clinical investigation. However, in 1980, successful cloning of the mature human alpha-A interferon led to the production of large quantities of bacterially synthesized human alpha-A interferon, now designated interferon alfa-2a (Roferon-A, Hoffmann-La Roche, Nutley, NJ). This abundance of alfa-2a made possible clinical studies of alpha interferon's capacity to suppress CML Philadelphia (Ph1) clones as well as restore the cells with normal karyotype. The data resulting from these clinical trials indicate that interferon alfa-2a is effective in inducing hematologic remissions in the majority of minimally treated, benign-phase CML, Ph1-positive patients. In some of the patients, treatment resulted in Ph1 chromosome suppression in the bone marrow and in the emergence of cells with a normal karyotype.

Antineoplastic Agents↗
PubMed1987

Clinical and prognostic features of patients with Philadelphia chromosome-positive chronic myelogenous leukemia and extramedullary disease.

Twenty-four patients who developed extramedullary disease during the course of Philadelphia chromosome-positive chronic myelogenous leukemia are described. The most frequent sites of extramedullary disease were lymph nodes (54%), bone (37%), and skin and soft tissue (29%). The appearance of extramedullary disease was associated with a high incidence of other features of accelerated disease (37%) and with cytogenetic clonal evolution (62.5%). The median time from extramedullary disease to blastic crisis was 4 months, and the median survival was 5 months. At the time of analysis, 23 patients have died, 16 after evolving into blastic crisis, and 7 from progressive disease without satisfying the criteria of medullary blastic crisis. This study confirms the importance of extramedullary disease as a sign of poor prognosis in chronic myelogenous leukemia, and the need for alternate therapies when such an event develops.

Bone Neoplasms↗
PubMed1987

Clinical and laboratory changes induced by alpha interferon in chronic lymphocytic leukemia--a pilot study.

Ten chronic lymphocytic leukemia patients were treated with partially pure alpha interferon (IFN-alpha) at doses ranging from 3-9 X 10(6) units administered intramuscularly daily. Of these patients, three patients with disease stages 0, 1, and 3 (and prolymphocytic leukemia), respectively, responded with partial remissions lasting from 10 to 24+ months; four additional patients had minor responses. Among those responding, modulation of B cell chronic lymphocytic leukemia, surface immunoglobulins, and surface antigens were observed in four patients. These changes included a decline in the proportion of B cells bearing surface immunoglobulin without change in the number of the B cells. Likewise, a decline in the proportion of B cells bearing T-1 antigen was observed in three patients. Increase in the percentage of T cells, primarily the T helper cells, was seen in two of the responding patients. Specific binding of alpha interferon was demonstrated prior to therapy in CLL cells of all patients. This binding declined rapidly following treatment with IFN-alpha. Induction of the enzyme 2'5' oligoisoadenylate synthetase was examined in CLL patients prior to and during therapy with IFN-alpha. Variable levels of the enzyme were induced in all patients on therapy; however, only minimal induction was observed in two of three patients failing therapy.

2',5'-Oligoadenylate Synthetase↗
PubMed1987

Chronic myelogenous leukemia in blast crisis. Analysis of 242 patients.

Two hundred forty-two patients with Philadelphia chromosome-positive chronic myelogenous leukemia in blast crisis were reviewed to identify significant biologic and prognostic associations. Twenty percent of patients had lymphoid blast crisis. Clonal evolution was present in 60 percent of patients at blast crisis and involved most frequently the development of a double Philadelphia chromosome, trisomy 8, or isochromosome 17. The overall median survival from blast crisis was 18 weeks. Patient characteristics demonstrated to have significant association with short survival were: anemia; thrombocytopenia; myeloid or undifferentiated blast cell morphology; clonal evolution involving the presence of a double Philadelphia chromosome, trisomy 8, or isochromosome 17; and low marrow blast percentage. Of 195 patients who received therapy for blast crisis, complete remission was achieved in 44 (23 percent) patients, and 24 (13 percent) patients had a partial remission or hematologic improvement. Lower complete remission rates were associated with old age, thrombocytopenia, myeloid or undifferentiated blast cell morphology, clonal evolution--especially isochromosome 17 and trisomy 8--and long interval from diagnosis to onset of blast crisis. A multivariate analysis identified two characteristics to have independent prognostic importance for both survival and remission: platelet counts and blast cell morphology. In addition, clonal evolution had additive prognostic value for survival (double Philadelphia chromosome) and for response (isochromosome 17). The beneficial association of therapy with survival was demonstrated by the significantly longer median survival of patients treated since 1981 compared with those treated earlier, even after accounting for the pretreatment prognostic factors, and by the significant improvement in survival of patients achieving remission using the "landmark" analysis technique.

Blast Crisis↗
PubMed1987

Molecular characteristics of chronic myelogenous leukemia in blast crisis.

We have studied the expression of c-abl and c-myc in leukemic cells of patients in all clinical phases of chronic myelogenous leukemia. We demonstrate that an aberrant 8-Kb c-abl related transcript is present in the RNA of the leukemic cell from all patients with Ph+ CML and that the loss of both normal chromosome #9 is associated with the loss of the normal c-abl related transcripts. This represents direct evidence that the normal c-abl related transcripts derive from the normal c-abl gene locus on the normal chromosome #9, while the aberrant c-abl related transcript in Ph+ CML derives from the hybrid bcr-abl gene formed as a result of the t(9;22). We further demonstrate that trisomy 8 in some instances is associated with enhanced expression of the c-myc oncogene.

Blast Crisis↗
PubMed1987

Molecular analysis of chromosome 22 breakpoints in adult Philadelphia-positive acute lymphoblastic leukaemia.

The Philadelphia (Ph) translocation, t(9:22)(q 34:q11), is found in the majority of patients with chronic myelogenous leukaemia (CML) as well as in approximately 20% of adult acute lymphoblastic leukaemia (ALL) patients. The chromosome 22 breakpoint in CML has been localized within a restricted 5.8 kb segment of DNA known as the breakpoint cluster region (bcr). To investigate the chromosome 22 breakpoint in ALL, we analysed five adult Ph-positive ALL patients for bcr rearrangement. Rearrangement was detected within bcr in two patients. However, in one patient the break occurred 5' to the first exon of bcr and in two patients the bcr region was not involved. We conclude that the identical cytogenetic marker, t(9:22), may yield a different genomic configuration in ALL and CML.

Acute Disease↗
PubMed1987

Intensive combination chemotherapy and interferons in the management of chronic myelogenous leukemia.

Compared to single-agent therapy with hydroxyurea or myleran (155 patients), intensive chemotherapy with vincristine, cytosine arabinoside, prednisone and cyclophosphamide (60 patients) or anthracyclines (37 patients) showed significant survival improvement overall (p less than 0.01) and among intermediate- and high-risk patients. Of 51 patients treated with human leukocyte alpha interferon (IFN-alpha), 36 (71%) had complete hematologic remission (CHR); 20 patients (39%) showed Ph suppression which was persistent in 13 for greater than 21 months. Survival was better in patients obtaining remission with IFN-alpha. Recombinant gamma interferon (IFN-gamma) was also active in chronic myelogenous leukemia. Therapy with combined IFN-alpha + IFN-gamma has been initiated. Compared to the expected survival, the observed survival is favorable for IFN-alpha and the combined chemotherapy and IFN-alpha programs. Future therapeutic trials will incorporate initial IFN therapy followed by cyclic intensive chemotherapy at 6-month intervals and IFN maintenance between chemotherapy cycles.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1987

Clonal nature of Philadelphia chromosome-positive and -negative chronic myelogenous leukemia by DNA hybridization analyses.

Evidence for the clonal nature of chronic myelogenous leukemia (CML) has been obtained primarily from studies of black females expressing polymorphic glucose-6-phosphate dehydrogenase (G6PD) isoenzymes where, instead of the heterozygous pattern normally found as a result of random X chromosome inactivation, exclusive expression of only one G6PD allele has been demonstrated in leukemic cell populations. We report here the use of two other molecular approaches to examine clonality of peripheral blood cells in patients with CML. The first of these is based on the analysis of consistent differential methylation patterns associated with active and inactive X chromosomes within the region spanned by a BamHI restriction fragment length polymorphism (RFLP) at the hypoxanthine phosphoribosyltransferase (HPRT) locus. By this method, three heterozygous females gave results consistent with monoclonal origin of the disease, including one patient lacking the Philadelphia chromosome (Ph1) normally associated with CML. In the other two patients, both of whom had Ph1-positive CML, clonality was confirmed by the demonstration of simple gene rearrangements by Southern hybridization with a breakpoint cluster region (bcr) probe from chromosome 22.

Adult↗