[Multidrug resistance in chronic lymphocytic leukemia]. / Multidrogrezisztencia-vizsgálatok krónikus lymphoid leukaemiában.

INTRODUCTION: New prognostic factors discovered in chronic lymphocytic leukemia have recently got into the center of clinical interest. While the predictive value of cytogenetical abnormalities, immunoglobulin heavy chain gene mutation status, CD38 and ZAP70 expression is already well known, the significance of multi-drug resistance in chronic lymphocytic leukemia is not well characterized. AIMS: The goal of this study was to characterize the multidrug resistance features in 82 patients with chronic lymphocytic leukemia at the genetical, expression- and functional level and to compare it with the patient's clinical behavior (survival and response to therapy). METHODS: Light Cycler Real Time PCR based "Single Nucleotide Polymorphism" analysis of the MDR1 gene, as a biological predictor of the expression level of P-glycoprotein was tested in 66 patients with chronic lymphocytic leukemia. P-glycoprotein expression and MDR-function was detected in 82 cases by flow cytometry (by use of anti-P-glycoprotein monoclonal antibody and calcein-verapamil functional test). Response to therapy was analyzed by statistical Fisher-test in the treated 35 patients. The survival analysis (Log-rank test) was performed on the whole population ( n = 82). RESULTS: No significant correlation was found between the three levels of multidrug resistance (genetics, phenotype, function) in our patients with chronic lymphocytic leukemia. P-glycoprotein positive cases (n = 9) were predominantly non-responders (8/9, 89%). There must be, however, other mechanisms causing non-response (total non-responders: 13/35 treated cases). Most of P-glycoprotein negative CLL patients (n = 26) responded well (21/26, 80%) to chemotherapy (responders: 22/35 treated CLL) (p < 0,001). The tendency was the same in the average expected survival rate between P-glycoprotein positive and negative patients (84 vs 203 months) but the difference was not significant (p = 0,106). CONCLUSIONS: This study proved the clinical prognostic significance of P-glycoprotein expression of leukaemic cells predicting the chemotherapy response and partially estimating the general survival of patients suffering from chronic lymphocytic leukemia.

Lineage-specific clonality analysis of chronic myeloproliferative disorders and myelodysplastic syndrome by human androgen receptor assay.

In myelodysplastic syndrome (MDS) as well as chronic myeloproliferative disorders (CMPD) others than chronic myeloid leukemia the frequency of pathognomonic genetic aberrations is very low and, therefore, X chromosome inactivation (XI) assays may help in assessing the clonality. To establish specific clonality criteria on XI, human androgen receptor assay (HUMARA) was performed on sorted myeloid and lymphoid peripheral blood cells of 21 healthy females. Clonality criteria 1 and 2 conferring at least 90% specificity were set based on the ranges and differences of XI number (XIN) describing the ratio of representation of the two alleles in as well as in between reactive myeloid and lymphoid compartments. Spiking experiments indicated that the test identifies clonality reliably when no more than 40-50% reactive cells are admixed. In the CMPD and MDS cases peripheral myeloid cells were monoclonal by one of the two criteria in 71-100%, whereas lymphoid cells in 28-75%. The results of HUMARA, available in 73% of the female patients, supported the clinicopathological data in 84% as well as proved pluripotent stem cell origin in 31-75% and 21% of CMPDs and MDS, respectively.

Multiple constitutional chromosome translocations of familial nature in Philadelphia chromosome-positive chronic myeloid leukemia: a report on a unique case.

A case of Philadelphia chromosome-positive (Ph(+)) chronic myeloid leukemia (CML) featuring 2 additional balanced translocations, t(2;5) and t(6;12), as well as a robertsonian translocation, t(13;14), was diagnosed by routine bone marrow karyotyping. The breakpoints did not involve previously described CML-related chromosomal regions in any of the 3 translocations. Despite the patient's partial response following imatinib therapy, all Ph(-) bone marrow metaphases persistently had the 3 additional chromosomal changes. Moreover, stimulated peripheral B-lymphocytes from the patient also showed the same chromosomal changes, suggesting that we had found a complex constitutional chromosome aberration unrelated to the leukemia. Peripheral blood karyotype analyses of 6 of the 7 closest relatives from 3 generations demonstrated at least 1 of these aberrations, although in different combinations. Standard bone marrow or peripheral blood karyotyping of hematologic disorders may uncover otherwise symptomless, unrelated constitutional changes together with disease-specific chromosome aberrations.A triple constitutional chromosome aberration combined with a hematologic disorder has not been described until now. In addition, multiple constitutional aberrations persisting through at least 3 generations seem to be extremely rare. At present, no direct evidence exists to support a causative relationship between the familial translocations and leukemogenesis.

[Tyrosine kinase inhibitor STI571: new possibility in the treatment of chronic myeloid leukemia]. / Uj lehetóség a krónikus myeloid leukaemia kezelésében: specifikus tirozinkináz-inhibitor (STI571).

Chronic myeloid leukemia shown to be associated with the Ph translocation,--characterised as a t(9;22)--, joins the bcr and abl genes and leads to expression of chimeric BCR-ABL protein with enhanced tyrosine kinase (TK) activity. This increased TK activity leads to malignant transformation by interference with the control of proliferation, cellular adherence and apoptosis. The presence of this protein in every CML cells is strong evidence of its pathogenetic role. Following this observations efforts were made to develop molecularly targeted therapies for CML. The specific inhibitor of BCR-ABL TK, STI571 was developed by Brian Druker and his co-workers in 1996. STI571 (Signal Transduction Inhibitor) occupies the kinase pocket of the BCR-ABL protein, and blocks ATP binding, thereby preventing phosphorylation of any substrate. Because of promising preclinical data STI571 entered clinical trials in 1998, using an oral formulation. The reports of this trials document excellent efficacy. Patients with chronic phase after failure with interferon therapy achieved more than 90% hematologic response, usually within 4-6 weeks, and 55% major cytogenetic response. Patients with advanced disease also responded, though less durably. In phase 2 studies the drug has continued to produce impressive results. STI571 has a very favourable pharmacologic feature, with high degree of specificity for its target, and therefore low toxicity for normal tissues, it is well tolerable, side effects were minimal. STI571 opens a new era in the treatment of malignancies, it is the first targeted molecular therapy which is able to target abnormal cells without damaging normal cells, compared with traditional antineoplastic drugs.

[Results of imatinib therapy in late-stage chronic myeloid leukemia after treatment with interferon-alpha]. / Imatinib kezelési eredmények krónikus myeloid leukaemia késói krónikus fázisában, interferon-alpha kezelés után.

BACKGROUND: Chronic myelogenous leukemia is characterised by the presence of Philadelphia translocation and consecutive expression of bcr-abl oncogene with enhanced tyrosine kinase activity, which is known to be the essential pathogenetic event in the disease. Imatinib (Glivec, formerly STI571) is a highly selective inhibitor of the bcr-abl tyrosine kinase which has shown a promising therapeutic activity in chronic myeloid leukemia as the first molecularly targeted antinoplastic treatment. METHODS: Between January 2001 and October 2001, 54 patients with chronic phase CML, resistant or intolerant to interferon-alpha were enrolled into the Novartis Expanded Access Study (Protocol 0113). Patients characteristics were as follows: male/female: 32/22, median age: 49 years (range: 22-75), median duration of disease: 44 months (range: 3-152). All patients received 400 mg imatinib orally. RESULTS: Complete hematologic response was obtained in 53 patients (96%) within 4 weeks. Major cytogenetic response (< 35% Ph+ metaphasis) was achieved after 6 months in 62.9%, and after 12 months in 64.8% of patients. Three patients progressed during the treatment (loss of complete hematologic response or cytogenetic response 1, blastic phase 2). The treatment was well tolerated, with mild side effects. Main non-hematologic side effects were weight gain and fluid retention. CONCLUSIONS: The results confirm that imatinib is highly active in inducing complete hematologic response and major cytogenetic response in most patients who failed interferon-alpha. Treatment was well tolerated with rare and mild adverse events and impressive improvement of quality of life.

Clinical importance of transforming growth factor-beta but not of tumor necrosis factor-alpha gene polymorphisms in patients with the myelodysplastic syndrome belonging to the refractory anemia subtype.

OBJECTIVES: Tumor necrosis factor-alpha (TNF-alpha) and transforming growth factor-beta (TGF-beta) are cytokines that play key roles in the myelodysplastic syndrome (MDS). There have been several reports on the presence of genetic polymorphisms in the DNA sequence encoding the leader sequence of the TGF-beta1 protein, located in codon 10 in exon 1 and in the -308 promoter region of TNF-alpha. The objective of this study was to investigate the association between TNF-alpha and TGF-beta1 gene polymorphisms and the susceptibility to MDS and the progression of the disease among patients with MDS belonging to the refractory anemia (RA) subtype. METHODS: The diagnosis of MDS (n = 50) was based on the FAB criteria. The TNF-alpha genotypes were analyzed by PCR-RFLP and the TGF-beta genotypes were analyzed using an amplification refractory mutation system. RESULTS AND CONCLUSIONS: Compared with healthy control subjects, patients with RA showed no significant deviations in genotype or allele frequencies of TNF-alpha. The TT homozygosity at codon 10 of TGF-beta1 was significantly higher among patients with bi- or pancytopenia (severe group) than in the patients with anemia only (mild group; odds ratio = 6.99, p = 0.003). These findings suggest that the TGF-beta1 gene polymorphism in codon 10 and the -308 TNF-alpha gene polymorphism do not predispose to the development of RA, but the TGF-beta1 gene polymorphism may affect disease progression.