T. Karakas

High expression of bcl-2 mRNA as a determinant of poor prognosis in acute myeloid leukemia

BACKGROUND The bcl-2 oncoprotein is suggested to be directly involved in the emergence of drug resistance by disrupting or delaying the apoptotic program and promoting tumor survival. PATIENTS AND METHODS In order to define the clinical relevance of the bcl-2 mRNA expression in acute myeloid leukemia (AML) and its correlation to therapy outcome and prognosis, we analyzed 219 AML bone marrow (BM) samples, including 119 patients with de novo AML at presentation, 37 with AML following myelodysplastic syndrome (MDS), as well as 42 BM samples of AML in relapse and 21 in complete remission (CR) using RT-PCR. For performing quantitative measurements of bcl-2 mRNA, we developed a quantitative RT-PCR. RESULTS Bcl-2 mRNA was detectable in 133 of 156 (84%) patients at diagnosis and 40 of 42 (95%) at relapse. AML patients with high bcl-2 mRNA expression achieved lower CR rates than those with no or low expression. Concerning the long-term outcome, the overall (OS) and disease-free survival (DFS) was significantly worse in AML patients with high expression levels of bcl-2 mRNA. The three-year OS for all newly diagnosed AML patients was 49% and 10% (P = 0.028), respectively, and 71% and 15% (P = 0.0004) for patients < 60 years. Comparable significant differences were observed for the DFS. In AML following MDS and patients > 60 years, the bcl-2 expression was not associated with remission rate or survival. CONCLUSIONS The expression of bcl-2 mRNA may serve as a prognostic factor predicting remission outcome and long-term prognosis in AML.

The coexpression of the apoptosis-related genes bcl-2 and wt1 in predicting survival in adult acute myeloid leukemia.

The Wilms tumor gene wt1 and the protooncogene bcl-2 are upregulated in acute myeloid leukemia (AML) and are known to regulate or to inhibit the onset of apoptosis. Since wt1 has been shown to regulate the expression of bcl-2, we investigated the association of the expression of these genes and their prognostic relevance in AML. Leukemic blasts from the bone marrow of 152 patients with newly diagnosed AML were analyzed for bcl-2 and wt1 mRNA expression using RT-PCR and quantitative PCR. Therapy outcome was correlated with the level of bcl-2 and wt1 transcripts. Bcl-2-specific mRNA was detectable in 127/152 (84%) patients and wt1 mRNA in 113/152 (74%) patients with AML. In monocytic subtypes the frequency of bcl-2 and wt1 transcripts was significantly lower. The expression of bcl-2 mRNA was correlated significantly with that of wt1 mRNA (P < 0.0001). In AML patients <60 years, high expression of bcl-2 and wt1 was associated with a reduced rate of continuing complete remission (CCR, P = 0.002 and P = 0.005, respectively) and increased death rate (P = 0.0002 and P = 0.04, respectively) in contrast to patients >60 years, where the expression of bcl-2 or wt1 had no prognostic impact. Based on the coexpression of bcl-2 and wt1, we established a prognostic model defining three risk groups with significant differences in CCR rate (P = 0.01), overall survival (P < 0.04) and disease-free survival (P < 0.03). Thus, bcl-2 and wt1 mRNA expression are associated with response and long-term outcome in AMLs. The coexpression of these genes allows determination of prognostic groups with high predictive value for overall and disease-free survival.

Peripheral T-cell Lymphomas Respond Well to Vincristine, Adriamycin, Cyclophosphamide, Prednisone and Etoposide (VACPE) and Have a Similar Outcome as High-Grade B-Cell Lymphomas

Peripheral T-cell lymphomas (PTCL) represent a heterogeneous group of T-cell malignancies including subentities with favourable (large cell anaplastic) or unfavourable (pleomorphic) prognosis. The clinical outcome of PTCL has been controversially discussed, but a worse prognosis than high-grade B-cell Non-Hodgkins lymphomas (NHL) has been postulated by most authors. In this report we summarize the results of a prospective comparative study investigating the therapy outcome of 27 patients (pts) with PTCL and 55 pts. with high grade B-cell NHL and give an overview of therapy studies in PTCL. The histological subtypes were 14 pleomorphic, 8 large-cell anaplastic (Ki-1+), 2 angioimmunoblastic (AILD) and 3 other PTCL. In three patients the PTCL was associated with non-tropical sprue (11%). Nineteen patients presented with an advanced stage of disease (stage III and IV, 70%), 17 (63%) pts. had B-symptoms. The patients were treated with vincristine 2 mg d1, adriamycin 25 mg/m2 d1-3, cyclophosphamide 800 mg/m2 d1, prednisone 60 mg/m2 d1-7 and etoposide 120 mg/m2 d1-3 (VACPE). In 77% of pts. with PTCL and 84% of patients with high-grade B-cell NHL a complete remission (CR) was achieved. 75% of the complete responders with PTCL and 70% with B-NHL are still in ongoing CR. The subgroup of large-cell anaplastic attained a CR in 88%. The median observation time is 44 months (1(+)-77+). The probability of 1-, 3- and 5-year overall and disease-free survival for the T-cell group were 76%, 54%, 48% and 76%, 62%, 62%, respectively according to Kaplan-Meier. There was no significant difference regarding the remission rate, the overall-, event-free or disease-free survival compared to high-grade B-cell lymphomas. In conclusion, the VACPE regimen is an effective and feasible regimen in the management of PTCL achieving complete remissions in a large proportion of patients.

Bendamustine in the Treatment of Low-Grade Non-Hodgkin’s Lymphomas

Bendamustine is a nitrogen mustard derivative, devel-oped in East Germany in the early 60s in search for new cytotoxic drugs belonging to the group of alkylating drugs. With regard to its structure, an action as a purine analogue must be assumed, too. Bendamustine induces long-lasting DNA strand breaks and apoptosis. So far, bendamustine did not show cross resistance with various other chemotherapeutics including alkylating agents as chlorambucil or cyclophosphamide. Recent clinical studies revealed major activity of bendamustine in low-grade non-Hodgkin’s lymphomas (NHL), chronic lymphocytic leukemias (CLL), and multiple myelomas (MM). The response rate (RR) varied between 59 and 97% in relapsed or refractory low-grade NHL, 69–94% in CLL, and 52–75% in MM. Therefore, bendamustine seems to be one of the most active single agents in low-grade NHLs comparable to the activity of purine analogues. The experience of combination of bendamustine with other cytostatics, however, is still rare. The toxicity profile of bendamustine showed only a low emetogenicity, no induction of alopecia and a myelosuppression comparable to that of other alkylating agents. The present data suggest bendamustine as a highly effective drug in refractory or relapsing low-grade NHL including CLL and MM. Its relevance in the second- and third-line therapy as well as in first-line schedules as a single agent and in combinations will have to be elucidated by further studies.

Recombinant human granulocyte-macrophage colony-stimulating factor after combined chemotherapy in high-grade non-Hodgkin's lymphoma--a randomised pilot study.

High-grade non-Hodgkins lymphomas (NHL) can potentially be cured with combination chemotherapy, although the optimum schedules still have to be defined. Clinical trials with intensive chemotherapy are predominantly limited by myelosuppression. Here, haematopoetic growth factors open up the possibility of reducing chemotherapy-associated toxicities. In this randomised pilot study, we investigated the effects of a recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) following combined chemotherapy with vincristine, doxorubicin, cyclophosphamide, prednisone and etoposide (VACPE). A total of 35 patients with high-grade NHLs were randomised to receive either rhGM-CSF or placebo during the first two chemotherapy cycles and rhGM-CSF for all following cycles. rhGM-CSF was administered at a dosage of 5 micrograms/kg for 10 days or until neutrophils were > 1/nl following chemotherapy. The analyses revealed a significant reduction of neutropenia and duration of neutropenia in the rhGM-CSF group. Adverse events were rare and generally mild apart from one anaphylactoid reaction. No effects of rhGM-CSF were observed concerning the platelet nadir or duration of thrombocytopenia. The benefit of rhGM-CSF for response induction and survival via rhGM-CSF-supported dose intensification remains to be determined.

Establishment and characterization of a new, factor-independent acute myeloid leukemia line designated Ei501

We established a factor-independent acute myeloid leukemia cell line, designated Ei501. The line has been growing in RPMI 1640 media for 18 months and can be maintained without addition of growth factors. Ei501 is positive for myeloperoxidase and negative for esterase and PAS. Cytogenetic analysis revealed the FAB M3 associated t(15;17) translocation and a translocation of the chromosomes 7 and 8: 46 XX, −7, +t(7;8)(q32;q13), t(15;17)(q22;q12). This karyotype was confirmed by fluorescence in situ hybridization. Ei501 cells express AML-associated surface markers such as CD13, CD33 and CD38. Although 42% of the patient’s blast cells were CD34-positive, the line lacks surface expression of CD34. Furthermore the line has a number of characteristics which are detectable in blasts from AML patients, such as surface adhesion molecules, cytokines such as TGF-β, cytokine receptors such as the IL-2 receptor β and γ chains or the IL-4 receptor and the genes for the transcription factor wt- 1 (Wilms’ tumor gene) and for the proto-oncogene bcl-2, both shown to be present in the majority of patients with AML. Additionally the line can be used as target in cytotoxicity assays using IL-2 activated cytotoxic lymphocytes as effector cells. In conclusion, besides a rare karyotype the Ei501 cell line has several features common in AML, and may therefore be used as a model to study pathogenetic mechanisms in acute myeloid leukemia.