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The influence of interferon- (IFN) pretreatment on the outcome after allogeneic bone marrow transplantation (BMT) in chronic myelogenous leukemia (CML) is controversial. One goal of the German randomized CML Studies I and II, which compare IFN ± chemotherapy versus chemotherapy alone, was the analysis of whether treatment with IFN as compared to chemotherapy had an influence on the outcome after BMT. One hundred ninety-seven (23%) of 856 Ph/bcr-abl–positive CML patients were transplanted. One hundred fifty-two patients transplanted in first chronic phase were analyzed: 86 had received IFN, 46 hydroxyurea, and 20 busulfan. Forty-eight patients (32%) had received transplants from unrelated donors. Median observation time after BMT was 4.7 (0.7 to 13.5) years. IFN and chemotherapy cohorts were compared with regard to transplantation risks, duration of treatments, interval from discontinuation of pretransplant treatment to BMT, conditioning therapy, graft-versus-host disease prophylaxis and risk profiles at diagnosis and transplantation, and IFN cohorts also with regard to performance and resistance to IFN. Outcome of patients receiving related or unrelated transplants pretreated with IFN, hydroxyurea, or busulfan was not significantly different. Five-year survival after transplantation was 58% for all patients (57% for IFN, 60% for hydroxyurea and busulfan patients). The outcome within the IFN group was not different by duration of prior IFN therapy more or less than 5 months, 1 year, or 2 years. In contrast, a different impact was observed in IFN-pretreated patients depending on the time of discontinuation of IFN before transplantation. Five-year survival was 46% for the 50 patients who received IFN within the last 90 days before BMT and 71% for the 36 patients who did not (P = .0057). Total IFN dosage had no impact on survival after BMT. We conclude that outcome after BMT is not compromised by pretreatment with IFN if it is discontinued at least 3 months before transplantation. Clear candidates for early transplantation should not be pretreated with IFN.

Microsatellites are important highly polymorphic genetic markers dispersed in the human genome. Using a panel of 22 (CA)n repeat microsatellite markers mapped to recurrent breakpoint cluster regions specifically involved in leukemia, we investigated 114 adult leukemias (25 acute lymphocytic leukemia [ALL], 32 acute myeloid leukemia [AML], 36 chronic lymphocytic leukemia [CLL], and 21 chronic myeloid leukemia [CML] in chronic phase) for somatic mutations at these loci. In each patient, DNA from fresh leukemia samples was analyzed alongside normal constitutive DNA from buccal epithelium. We detected loss of heterozygosity (LOH) in 81 of 114 patients (ALL 16/25, AML 25/32, CLL 30/36, CML 10/21). Deletions were most often seen in ALL at 11q23 and 19p13; in AML at 8q22 and 11q23; in CLL at 13q14.3, 11q13, and 11q23; and in CML at 3q26. Only six deletions were reported in 74 karyotypes analyzed, whereas in these same cases, 91 LOH events were detected by microsatellites. Of 26 leukemias with a normal karyotype, 16 nevertheless showed at least one LOH by microsatellite analysis. Replication errors were found in 10 of 114 patients (8.8%). Thus, microsatellite instability is rare in leukemia in contrast to many solid tumors. Our findings suggest that in adult leukemia, LOH may be an important genetic event in addition to typical chromosomal translocations. LOH may point to the existence of tumor suppressor genes involved in leukemogenesis to a degree that has hitherto been underestimated.

Id proteins are helix-loop-helix (HLH) transcriptional factors that lack the basic DNA binding domain. The Id proteins have been reported generally to function as inhibitors of cell differentiation, and their gene expression is often downregulated during cell differentiation. We examined the expression of human Id mRNAs by Northern hybridization in 11 human myeloid cell lines, several myeloid cell lines induced to differentiate, fresh myeloid leukemia samples, and normal human myeloid cells. Id2 mRNA was expressed in myelomonoblastic and monoblastic leukemic cells (PLB-985, THP-1, and U-937) but was weakly expressed in myeloblastic leukemic cells (KG-1 and HL-60). Id2 mRNA levels markedly increased with induction of differentiation of myeloid blasts (HL-60, PLB-985, THP-1, and U-937) toward either granulocytes or macrophages. Examination of fresh acute myeloid leukemic samples from 22 individuals also showed prominent Id2 mRNA expression in those samples having more differentiated blasts. Using the French-American-British classification, only 2 of 8 M0/M1 samples expressed Id2 mRNA; however, 10 of 13 M2/M3/M4 samples expressed it. In normal human myeloid cells, Id2 mRNA was expressed in cultured macrophages from bone marrow and in mature granulocytes and monocytes from peripheral blood. The half-life of Id2 mRNA was short (1 hour), and its expression was inducible by cessation of protein synthesis. Id3 mRNA was moderately expressed in monoblastic cell lines (THP-1 and U-937), and levels decreased with their differentiation. Almost no Id3 expression was detectable in either other myeloid leukemia lines, fresh leukemic samples, or normal human myeloid cells by Northern analyses. Id1 mRNA was not detected by polymerase chain reaction in either leukemic or normal myeloid cells except in K562 myeloid/erythroid cells. These results showed that Id2 mRNA was constitutively expressed in more mature myeloid blast cells and level markedly increased with terminal myeloid differentiation, suggesting that Id2 protein may inhibit an HLH transcriptional complex that normally represses myeloid differentiation.

A newly recognized family of proteins that inhibit cyclin-dependent kinases (CDKs) termed cyclin-dependent kinase inhibitors (CDKI) have an important role in regulation of cell-cycle progression. A subfamily of these CDKIs (p15INK4B/MTS2, p16INK4/MTS1, and p18) have a high degree of structural and functional homology and are candidate tumor- suppressor genes. We evaluated the mutational status of the p15, p16, and p18 genes in 103 childhood acute lymphoblastic leukemia (ALL) samples and correlated these results with both their clinical data and additional results concerning their loss of heterozygosity in the region of the p15/p16 genes. Homozygous deletions of the p16 gene occurred extremely frequently in T-ALLs (17/22; 77%), and it was also frequent in precursor-B ALLs (12/81; 15%). Homozygous deletions of the p15 gene were also very frequent in T-ALLs (9/22; 41%), and it occurred in 5 of 81 (6%) precursor-B ALL samples. No deletions of p18 was found in any of the 103 ALL samples. Also, no point mutations of the p15, p16, and p18 genes were detected. We correlated p15/p16 alterations at diagnosis with their clinical characteristics as compared with 2,927 other patients treated similarly. Those with p15/p16 alterations were older; had higher white blood cell counts, often with T-cell ALL phenotype; and more frequently had a mediastinal mass at presentation; but they had the same nonremission, relapse, and survival rates at 5 years as did those patients whose blast cells did not have a p15/p16 deletion. To better understand the extent of alterations affecting chromosome 9p21 (location of the p15/p16 genes), loss of heterozygosity (LOH) was examined at D9S171, which is about 1 megabase proximal to the p15/p16 genes. LOH was detected in 15 of 37 (41%) informative samples. Interestingly, of the 24 informative samples that had no detectable alteration of the p15/p16 genes, 7 samples (29%) had LOH at D9S171. In summary, we show in a very large study that p15 and p16, but not p18, CDKI genes are very frequently altered in ALL; those with p15/p16 alterations are more frequently older children, have higher white blood cells at presentation, and often have a T-cell ALL phenotype. The LOH analysis suggests that another tumor-suppressor gene important in ALL also is present on chromosome 9p21.

Interleukin-12 (IL-12), a cytokine with in vitro and in vivo immunomodulatory effects, is produced by lymphocytes and stimulated monocytes. Little is known about the production and possible role of IL-12 in human lymphoproliferative disorders. We examined IL-12 expression by immunohistochemistry using antibodies recognizing the p40, p35 subunits, and the p70 heterodimeric IL-12 protein, and by Northern blot in lymph nodes from patients with Hodgkin's disease (HD), non-Hodgkin's lymphomas (NHL), and nonneoplastic lymphoid lesions. In the majority of the HD cases (28 of 34), IL-12 immunoreaction was found in small lymphoid cells cultured around Hodgkin and Reed-Sternberg (H&RS) cells. No IL-12 signal was seen in H&RS cells. Transcripts for IL-12 were found by Northern and dot blot analysis in 13 of 19 (IL-12 p40) and 11 of 19 (IL-12 p35) cases. The HD cases were further examined for the presence of Epstein-Barr virus (EBV) latent membrane protein (LMP-1). All cases with EBV-LMP-1 positivity (22 of 34 cases) also expressed IL- 12. No IL-12 immunoreaction was found in neoplastic cells of 33 cases of various NHLs, which were all LMP-1 negative and showed no EBV-genome sequence, as assessed by polymerase chain reaction (PCR). In 24 nonneoplastic lymphoid lesions, few dispersed IL-12 positive cells were seen in the parafollicular area and in the sinus of the lymph node. The marked presence of IL-12 in the majority of HD cases indicates that IL-12 might play a role in the pathobiology of HD, suggesting that this cytokine is involved in EBV-positive HD.

About 80% to 90% of females are informative for X- inactivation/methylation analysis with the probe M27 beta, which would therefore seem attractive in assessing clonality in hematologic cell populations. Eighteen acute lymphoid or myeloid leukemias, three chronic lymphocytic leukemias, and three chronic myelogenous leukemias as well as 12 malignant non-Hodgkin's lymphomas mostly showed extremely skewed clonal X inactivation (median allelic cleavage ratio [ACR] of unmethylated/inactive M27 beta alleles was 50, range 1 to 100) or hypermethylation of both alleles. Two lymphomas showed random M27 beta X inactivation but clonal antigen-receptor gene rearrangements. In normal peripheral blood leukocytes from 105 healthy females aged 2 to 96 years, the median ACR was 2 (range 1 to 100). Thus, it was significantly lower than in the leukemias (P = .0001, Mann-Whitney test), but extremely skewed patterns (ACR > 10.8, ie, >80th percentile) were seen not only in the leukemias but also in 21/105 samples (20%) of normal leukocytes, and significantly more frequent in a population of elderly women (aged 75 to 96 years) compared with healthy children (aged 2 to 8 years) and younger women (aged 20 to 58 years) (P =.00125; chi 2 test). We conclude that in a population of cells derived from the hematopoietic system where clonality is uncertain, skewed M27 beta patterns are not reliable indicators for the presence of a clonal neoplastic disorder. The basis for severe X-inactivation skewing is unclear at present, but this finding raises interesting questions regarding the composition of the hematopoietic stem cell pool.

Cytokines such as granulocyte-macrophage colony-stimulating factor (GM- CSF), macrophage-CSF (M-CSF), neutrophil-activating peptide- 1/interleukin-8 (NAP-1/IL-8), and interleukin-6 (IL-6) are pivotal in the regulation of hematopoiesis and immune responses. In mesenchymal cells, their expression is induced by tumor necrosis factor alpha (TNF) and other agents. We now show that, while induction of cytokine expression by TNF in human lung fibroblasts was parallel, glucocorticoid hormones differentially affected their production. Dexamethasone (1 mumol/L) concordantly repressed expression of GM-CSF, NAP-1/IL-8 and IL-6. RNA and protein levels were reduced to approximately 5%, 20%, and 30% of control cells, respectively, as determined by Northern blot analyses and immunoassays. A 50% reduction of RNA levels for all three cytokines occurred in the range of 1 hour. In contrast, dexamethasone (1 mumol/L) did not decrease M-CSF RNA levels and protein release. M-CSF RNA and protein levels were maintained even when dexamethasone (1 mumol/L) was present for the whole duration of a 48-hour TNF stimulation. Further experiments showed that dexamethasone downregulates expression of GM-CSF, NAP-1/IL-8, and IL-6 mainly by decreasing the mRNA stability of these cytokines, and that the dexamethasone-mediated repression of cytokine expression depends on ongoing protein and RNA syntheses. Our study suggests that glucocorticoid hormones repress expression of a set of cytokine genes important in conditions of stress. However, they seem not to affect M- CSF expression, which is likely to be more crucial in maintaining long- term functions of myeloid cells.

Tumor necrosis factor alpha (TNF alpha) stimulates granulocyte- macrophage colony-stimulating factor (GM-CSF) production in human fibroblasts and other mesenchymal cells. However, relatively little is known about agents that downregulate cytokine production in these cells. In the present report we show that dexamethasone (Dexa), a synthetic glucocorticoid, markedly reduced GM-CSF production in TNF alpha-stimulated fibroblasts at both the protein and the RNA levels. CSF activity, GM-CSF protein, and RNA levels, determined by an in vitro colony-forming assay in normal human bone marrow cells, by an enzyme immunoassay, and by Northern blotting assay, were reduced to greater than 90% of control values by Dexa (1 mumol/L). Similarly, 1,25- dihydroxyvitamin D3 [1,25(OH)2D3], a hormone with possible physiologic immunoregulatory significance, reduced GM-CSF expression in a concentration- and time-dependent manner. However, this repression was less pronounced than that of Dexa, and in part due to a decreased proliferative activity. In contrast, cyclosporine A (CsA), another immunosuppressive agent, did not alter GM-CSF expression in TNF alpha- stimulated fibroblasts. Our in vitro studies suggest that by inhibiting GM-CSF production in fibroblasts, glucocorticoids and possibly 1,25(OH)2D3, but not CsA, may attenuate TNF alpha-mediated inflammatory processes and influence the regulation of hematopoiesis.

Tumor necrosis factor alpha (TNF alpha) stimulates granulocyte- macrophage colony-stimulating factor (GM-CSF) production in human fibroblasts and other mesenchymal cells. However, relatively little is known about agents that downregulate cytokine production in these cells. In the present report we show that dexamethasone (Dexa), a synthetic glucocorticoid, markedly reduced GM-CSF production in TNF alpha-stimulated fibroblasts at both the protein and the RNA levels. CSF activity, GM-CSF protein, and RNA levels, determined by an in vitro colony-forming assay in normal human bone marrow cells, by an enzyme immunoassay, and by Northern blotting assay, were reduced to greater than 90% of control values by Dexa (1 mumol/L). Similarly, 1,25- dihydroxyvitamin D3 [1,25(OH)2D3], a hormone with possible physiologic immunoregulatory significance, reduced GM-CSF expression in a concentration- and time-dependent manner. However, this repression was less pronounced than that of Dexa, and in part due to a decreased proliferative activity. In contrast, cyclosporine A (CsA), another immunosuppressive agent, did not alter GM-CSF expression in TNF alpha- stimulated fibroblasts. Our in vitro studies suggest that by inhibiting GM-CSF production in fibroblasts, glucocorticoids and possibly 1,25(OH)2D3, but not CsA, may attenuate TNF alpha-mediated inflammatory processes and influence the regulation of hematopoiesis.

The most frequent chromosomal aberrations in B-cell chronic lymphocytic leukemia (B-CLL) are deletions on 13q, 11q, and 17p, and trisomy 12, all of which are of prognostic significance. Conventional cytogenetic analysis and fluorescence in situ hybridization (FISH) are used for their detection, but cytogenetic analysis is hampered by the low mitotic index of B-CLL cells, and FISH depends on accurate information about candidate regions. We used a set of 400 highly informative microsatellite markers covering all chromosomal arms (allelotyping) and automated polymerase chain reaction (PCR) protocols to screen 46 patients with typical B-CLL for chromosomal aberrations. For validation, we compared data with our conventional karyotype results and fine mapping with conventional single-site PCR. All clonal cytogenetic abnormalities potentially detectable by our microsatellite PCR (eg, del13q14 and trisomy 12) were picked up. Allelotyping revealed additional complex aberrations in patients with both normal and abnormal B-CLL karyotypes. Aberrations detectable in the samples with our microsatellite panel were found on almost all chromosomal arms. We detected new aberrant loci in typical B-CLL, such as allelic losses on 1q, 9q, and 22q in up to 25% of our patients, and allelic imbalances mirroring chromosomal duplications, amplifications, or aneuploidies on 2q, 10p, and 22q in up to 27% of our patients. We conclude that allelotyping with our battery of informative microsatellites is suitable for molecular screening of B-CLL. The technique is well suited for analyses in clinical trials, it provides a comprehensive view of genetic alterations, and it may identify new loci with candidate genes relevant in the molecular biology of B-CLL.

Microsatellites are important highly polymorphic genetic markers dispersed in the human genome. Using a panel of 22 (CA)n repeat microsatellite markers mapped to recurrent breakpoint cluster regions specifically involved in leukemia, we investigated 114 adult leukemias (25 acute lymphocytic leukemia [ALL], 32 acute myeloid leukemia [AML], 36 chronic lymphocytic leukemia [CLL], and 21 chronic myeloid leukemia [CML] in chronic phase) for somatic mutations at these loci. In each patient, DNA from fresh leukemia samples was analyzed alongside normal constitutive DNA from buccal epithelium. We detected loss of heterozygosity (LOH) in 81 of 114 patients (ALL 16/25, AML 25/32, CLL 30/36, CML 10/21). Deletions were most often seen in ALL at 11q23 and 19p13; in AML at 8q22 and 11q23; in CLL at 13q14.3, 11q13, and 11q23; and in CML at 3q26. Only six deletions were reported in 74 karyotypes analyzed, whereas in these same cases, 91 LOH events were detected by microsatellites. Of 26 leukemias with a normal karyotype, 16 nevertheless showed at least one LOH by microsatellite analysis. Replication errors were found in 10 of 114 patients (8.8%). Thus, microsatellite instability is rare in leukemia in contrast to many solid tumors. Our findings suggest that in adult leukemia, LOH may be an important genetic event in addition to typical chromosomal translocations. LOH may point to the existence of tumor suppressor genes involved in leukemogenesis to a degree that has hitherto been underestimated.

Id proteins are helix-loop-helix (HLH) transcriptional factors that lack the basic DNA binding domain. The Id proteins have been reported generally to function as inhibitors of cell differentiation, and their gene expression is often downregulated during cell differentiation. We examined the expression of human Id mRNAs by Northern hybridization in 11 human myeloid cell lines, several myeloid cell lines induced to differentiate, fresh myeloid leukemia samples, and normal human myeloid cells. Id2 mRNA was expressed in myelomonoblastic and monoblastic leukemic cells (PLB-985, THP-1, and U-937) but was weakly expressed in myeloblastic leukemic cells (KG-1 and HL-60). Id2 mRNA levels markedly increased with induction of differentiation of myeloid blasts (HL-60, PLB-985, THP-1, and U-937) toward either granulocytes or macrophages. Examination of fresh acute myeloid leukemic samples from 22 individuals also showed prominent Id2 mRNA expression in those samples having more differentiated blasts. Using the French-American-British classification, only 2 of 8 M0/M1 samples expressed Id2 mRNA; however, 10 of 13 M2/M3/M4 samples expressed it. In normal human myeloid cells, Id2 mRNA was expressed in cultured macrophages from bone marrow and in mature granulocytes and monocytes from peripheral blood. The half-life of Id2 mRNA was short (1 hour), and its expression was inducible by cessation of protein synthesis. Id3 mRNA was moderately expressed in monoblastic cell lines (THP-1 and U-937), and levels decreased with their differentiation. Almost no Id3 expression was detectable in either other myeloid leukemia lines, fresh leukemic samples, or normal human myeloid cells by Northern analyses. Id1 mRNA was not detected by polymerase chain reaction in either leukemic or normal myeloid cells except in K562 myeloid/erythroid cells. These results showed that Id2 mRNA was constitutively expressed in more mature myeloid blast cells and level markedly increased with terminal myeloid differentiation, suggesting that Id2 protein may inhibit an HLH transcriptional complex that normally represses myeloid differentiation.

Interleukin-12 (IL-12), a cytokine with in vitro and in vivo immunomodulatory effects, is produced by lymphocytes and stimulated monocytes. Little is known about the production and possible role of IL-12 in human lymphoproliferative disorders. We examined IL-12 expression by immunohistochemistry using antibodies recognizing the p40, p35 subunits, and the p70 heterodimeric IL-12 protein, and by Northern blot in lymph nodes from patients with Hodgkin's disease (HD), non-Hodgkin's lymphomas (NHL), and nonneoplastic lymphoid lesions. In the majority of the HD cases (28 of 34), IL-12 immunoreaction was found in small lymphoid cells cultured around Hodgkin and Reed-Sternberg (HRS) cells. No IL-12 signal was seen in HRS cells. Transcripts for IL-12 were found by Northern and dot blot analysis in 13 of 19 (IL-12 p40) and 11 of 19 (IL-12 p35) cases. The HD cases were further examined for the presence of Epstein-Barr virus (EBV) latent membrane protein (LMP-1). All cases with EBV-LMP-1 positivity (22 of 34 cases) also expressed IL-12. No IL-12 immunoreaction was found in neoplastic cells of 33 cases of various NHLs, which were all LMP-1 negative and showed no EBV-genome sequence, as assessed by polymerase chain reaction (PCR). In 24 nonneoplastic lymphoid lesions, few dispersed IL-12 positive cells were seen in the parafollicular area and in the sinus of the lymph node. The marked presence of IL-12 in the majority of HD cases indicates that IL-12 might play a role in the pathobiology of HD, suggesting that this cytokine is involved in EBV-positive HD.

About 80% to 90% of females are informative for X-inactivation/methylation analysis with the probe M27 beta, which would therefore seem attractive in assessing clonality in hematologic cell populations. Eighteen acute lymphoid or myeloid leukemias, three chronic lymphocytic leukemias, and three chronic myelogenous leukemias as well as 12 malignant non-Hodgkin's lymphomas mostly showed extremely skewed clonal X inactivation (median allelic cleavage ratio [ACR] of unmethylated/inactive M27 beta alleles was 50, range 1 to 100) or hypermethylation of both alleles. Two lymphomas showed random M27 beta X inactivation but clonal antigen-receptor gene rearrangements. In normal peripheral blood leukocytes from 105 healthy females aged 2 to 96 years, the median ACR was 2 (range 1 to 100). Thus, it was significantly lower than in the leukemias (P = .0001, Mann-Whitney test), but extremely skewed patterns (ACR10.8, ie,80th percentile) were seen not only in the leukemias but also in 21/105 samples (20%) of normal leukocytes, and significantly more frequent in a population of elderly women (aged 75 to 96 years) compared with healthy children (aged 2 to 8 years) and younger women (aged 20 to 58 years) (P = .00125; chi 2 test). We conclude that in a population of cells derived from the hematopoietic system where clonality is uncertain, skewed M27 beta patterns are not reliable indicators for the presence of a clonal neoplastic disorder. The basis for severe X-inactivation skewing is unclear at present, but this finding raises interesting questions regarding the composition of the hematopoietic stem cell pool.

Abstract 3281 Poster Board III-1 Introduction: In the two consecutive German CML studies III and IIIA (recruitment periods from 1995 to 2001 and 1997 to 2004), eligible patients were assigned to early HSCT by genetic randomization according to availability of a matched related donor. After randomization, 113 patients of study III (84% of 135) and 144 of study IIIA (87% of 166) were eventually transplanted in first chronic phase (CP) using a related donor. Despite comparable transplantation protocols and most centers participating in both studies, survival probabilities in study IIIA were significantly better, even when adjusted for the established EBMT risk score (Gratwohl et al., Lancet 1998 [1]), p + 0.0097. For further explanation, the German Registry for Stem Cell Transplantation (DRST) and the Swiss Transplant Working Group for Blood and Marrow Transplantation (STABMT) were asked for data support. Patients and Methods: The main sample characteristics of the 257 transplanted CML study patients were also applied to the registry patients: diagnosis of CML between 1994 and 2004, first HSCT with a related donor performed in first CP between 1995 and 2004 at an age between 12 and 65 years, and blood or bone marrow as stem cell sources. Thus, additional data of 582 HSCT patients were retrieved from the two registries. Age, recipient sex, donor sex, time between diagnosis and HSCT, calendar year of HSCT, stem cell source, and HLA matching were investigated as potential predictive factors for survival. Then, a sample of patients with the same risk distribution as the 113 patients of study III was randomly drawn from the registry patients. By application of repeated resampling to this new patient group, bootstrap confidence intervals for survival probabilities at various times after HSCT were extractable. This provided the basis to judge whether the survival in study III could be seen as a typical random representation of a sample with an equivalent risk structure or not. The same method was applied to the 144 patients of study IIIA. Results: The 5-year survival probability of all 839 patients resulted in 73% (229 died). Median follow-up time of living patients was 6.7 years. Due to the characteristic plateau of post-transplant survival probabilities, the predictive influence was judged by the Kaplan-Meier method and the log rank statistic. Also consideration of age and time between diagnosis and HSCT as continuous variables seemed less appropriate than working with categorizations. Furthermore, the previously published cut-points “1 year” for time from diagnosis to HSCT ([1]) and “44 years” for age at HSCT (Maywald et al., Leukemia 2006) were independently confirmed to be the best. Cox model and logistic regression with survival status after 3 years both indicated that age at HSCT, HLA matching, time between diagnosis and HSCT, and calendar year of HSCT had independent statistically significant predictive influence on survival (p < 0.05). The first two factors had the strongest effects. Calendar year was only influential when distinction was made between HSCT until and after 1999. All possible combinations of the 4 factors could be summarized in 4 risk groups with significantly different survival probabilities (at 5 years: 87%, 76%, 63%, and 24%). Matched for the risk group distribution of study III [study IIIA], a maximum of 290 [428] registry patients could be drawn. For the 290 [428] patients, 5-year survival was 69% [77%] with a 95% bootstrap confidence interval from 63% to 74% [72% to 81%]. Thus, as for all yearly intervals within the first 5 years, the 5-year survival probabilities of studies III: 65% and IIIA: 79% lied within the corresponding confidence intervals. Conclusions: Along with the registry patients, the study data enabled the identification of age at HSCT, HLA matching, time between diagnosis and HSCT, and calendar year of HSCT as factors with independent predictive impact on survival which led to 4 risk groups with statistically significantly different survival probabilities. More favorable-risk patients in study IIIA stood for a better transplantation strategy. In consideration of these different risks, the survival probabilities in both studies did not significantly vary from those of registry samples with matched risk structures. Accordingly, an improved transplantation strategy along with random variation could be considered as an explanation of the significantly different survival probabilities between the two studies. Disclosures: Haferlach: MLL Munich Leukemia Laboratory: Equity Ownership. Hochhaus:Novartis, Bristol-Myers Squibb: Research Funding. Hasford:Novartis: Research Funding. Gratwohl:AMGEN, Roche, Bristol-Myers Squibb, Novartis, Pfizer: Research Funding; Novartis: Consultancy. German CML Study Group:Kompetenznetz Leukämie, European Leukemia Net, Roche, Essex, AMGEN: Research Funding.

862 Rapid relapse after discontinuation of imatinib, the need for indefinite therapy and residual disease in most patients are the major challenges in management of CML. Combinations of imatinib with IFN simultaneously, or consecutively preceding imatinib, or with araC may improve treatment outcome. The German CML Study Group therefore designed a randomized trial to compare standard imatinib vs. imatinib + interferon alpha (IFN) vs. imatinib + low dose araC vs. imatinib after IFN failure (for low- and intermediate-risk patients, high risk patients received imatinib 800 mg instead). The current evaluation represents the prefinal results of the pilot phase of the trial. Inclusion criteria were newly diagnosed BCR/ABL positive CML in chronic phase (CP). Primary aims are: prolongation of survival (overall, OS, and progression free, PFS), determination of rates of hematologic, cytogenetic and molecular remissions, adverse events (AE) and role of allografting. By the end of 2005, 670 patients were randomized, 13 had to be excluded (no CML (n=3), pregnancy, no CP (n=1 each), imatinib 800 mg (n=8)). Analysis was according to intention to treat. 657 patients were evaluable (174 with imatinib 400 mg, 196 with imatinib+IFN, 158 with imatinib+araC and 129 with imatinib after IFN-failure). 656 patients were evaluable for hematologic, 611 for cytogenetic, and 618 for molecular responses. Patient characteristics of treatment arms were similar for age (median 53 years), sex (40% female), median values for Hb (12.6 g/dl), WBC (66.2/μl), platelets (383/μl) and for Euro risk score (low 35%, intermediate 54%, high 10%). The median dose of imatinib was 400mg/die in all arms, of araC 10 mg per treatment day and of IFN 4.2 Mio I.U./die in the imatinib after IFN arm and 1.8 Mio I.U./die in the imatinib+IFN arm. Median observation time was 57.3 months. 55 patients died, 73 patients were transplanted in 1st CP, 81 patients progressed, 59 patients were switched to second generation TKIs. After 3 years 126 patients (72%) of the imatinib 400mg arm still received the initial therapy as well as 60 patients (30%) of the imatinib+IFN arm and 53 patients (34%) of the imatinib+araC arm. 9 patients (7%) of the imatinib after IFN arm are still on IFN. 5-year OS of all patients is 91%. 5-year PFS of all patients (no death, patient still in first chronic phase) is 87%. 5-year-OS and PFS according to treatment arm are shown in the [Table][1]. At 5 years, the cumulative incidences of achieving complete cytogenetic remission or major molecular remission (MMR) as determined by competing risks (death, progression) are not different ([Table][1]). Type and severity of adverse events (AE) over a 5-years period did not differ from those reported previously ([Table][1]). Hematologic AEs grade III/IV were similar in all therapy arms except leukopenia grade III/IV, which was more frequently observed in the imatinib after IFN arm (14%). Non hematologic AEs were mainly fluid retention, neurological and gastrointestinal symptoms and fatigue. Neurologic symptoms and fatigue were more often reported for the therapy arms with IFN. | Imatinib 400mg | Imatinib+IFN | Imatinib+AraC | Imatinib after IFN | |:----------------------------------:| ------------ | ------------- | ------------------ | --- | | 5-Year Survival and Response Rates | | | | | | OS | 87% | 93% | 92% | 92% | | PFS | 84% | 91% | 88% | 84% | | CCR | 92% | 92 % | 89% | 83% | | MMR | 83% | 78% | 80% | 70% | | Adverse Events, WHO Grade III/IV | | | | | | Anemia | 7% | 1% | 3% | 3% | | Leukopenia | 4% | 5% | 2% | 14% | | Thrombocytopenia | 5% | 6% | 6% | 6% | | WHO Grade I-IV | | | | | | Edema | 15% | 13% | 5% | 0% | | Neurological | 5% | 15% | 5% | 22% | | Gastrointestinal | 17% | 27% | 21% | 15% | | Fatigue | 8% | 13% | 9% | 23% | This analysis shows excellent survival and durable response rates in all arms. Currently, survival in all treatment arms is equal to, or better than in IRIS. To verify possible differences in survival, e.g. imatinib 400 mg vs. imatinib + IFN, longer observation is planned. Although cytogenetic and molecular responses in the imatinib after IFN failure arm at 5 years are inferior to that in the other treatment arms, the question of whether the consecutive therapy with IFN first and imatinib after IFN-failure provides a survival advantage requires long term follow-up. Imatinib in combination with, or after IFN, or with low dose araC are feasible and safe treatment modalities. We expect that the study will optimize and improve therapy outcome in CML. Disclosures: German CML Study Group: Deutsche Krebshilfe: Research Funding; Novartis: Research Funding; German Competence Net : Research Funding; European LeukemiaNet: Research Funding; Roche: Research Funding; Essex: Research Funding. [1]: #T1

Abstract 339 Initial reports that high dose imatinib results in better responses more rapidly than standard dose imatinib remain controversial. The German CML Study Group therefore compared imatinib 800 mg (IM 800) with standard dose imatinib +/- IFN (IM 400, IM 400 + IFN) in newly diagnosed, not pretreated CML with regard to molecular response at 12 months and survival in a randomized clinical trial. By April 30, 2009, 1026 chronic phase CML patients have been randomized (326 for IM 400, 338 for IM 800, 351 for imatinib + IFN). Comparison was for molecular and cytogenetic remissions, overall (OS) and progression free (PFS) survival and toxicity. 1015 patients were evaluable at baseline, 904 for survival analysis (294 for IM 400, 286 for IM 800, 324 for IM 400+IFN), 790 for cytogenetic (analysis of at least 20 metaphases required) and 823 for molecular response. The three treatment groups were similar regarding median age, sex, median values of Hb, WBC, platelets and distribution according to the EURO score. Median follow-up was 25 months in the imatinib 800 mg arm and 42 months in the imatinib 400 mg +/-IFN arms. The difference is due to the fact that at first the IM 800 arm was designed for high risk patients only and opened up to all risk groups in July 2005. The median daily doses of imatinib were 626 mg (209- 800 mg) in the IM 800 arm and 400 mg (184- 720 mg) in the IM 400 +/- IFN arms. Of 218 patients receiving imatinib 800 mg and evaluable for dosage at 12 months, 100 (45.9%) received more than 700 mg/day, 27 (12.4%) 601-700 mg, 37 (17.0%) 501-600 mg, 48 (22.0%) 401-500 mg and only 6 (2.8%) 400 mg/day or less. The cumulative incidences at 12 months of complete cytogenetic remission (CCR) were 52.3%, 64.9% and 50.6%, and of major molecular remission (MMR) 30.2%, 54.3% and 34.6% with IM 400, IM 800 and IM 400 +IFN, respectively. The cumulative incidences of achieving CCR and MMR with IM 400, IM 800 and IM 400+IFN at 6, 12, 18 and 24 months after start of treatment are summarized in the table. MMR at 12 months was reached faster with IM 800 than with IM 400 (p=0.0003) or IM400+IFN (p=0.0131). Optimal molecular response (OMR= Disclosures: German CML Study Group: Deutsche Krebshilfe: Research Funding; Novartis: Research Funding; European LeukemiaNet: Research Funding; Kompetenznetz Leukämie: Research Funding; Roche: Research Funding; Essex: Research Funding.

The introduction of imatinib has significantly changed prognosis of CML patients. Despite favourable hematologic and cytogenetic response (CyR) data, patients (pts) on first line imatinib therapy may relapse. Thus, studies have been conducted to improve initial therapy by dose escalation or combination with other drugs. CML Study IV was designed to compare imatinib in standard dose (400 mg/d) vs high dose (800 mg/d) vs combinations with low dose cytarabine or interferon alpha. We sought to evaluate the predictive impact of early molecular response for long term event free survival (EFS). 539 pts (59% m, median age 54 years, range 16–84) randomized to imatinib based therapies by December 2005 were investigated, the median follow up was 39 mo (range, 0–69). At baseline, multiplex PCR was applied to determine the dominating BCR-ABL transcript: b2a2 (n=204), b3a2 (n=247), b2a2 and b3a2 (n=80), e1a2 (n=2), e19a2 (n=4), b3a3 (n=1) and e8a2 (n=1). Quantitative PCR from 5,419 peripheral blood samples was performed using the LightCycler technology in two central labs. PCR data were aligned to the international scale (IS) by introduction of conversion factors (Hughes et al., BLOOD 2006). Cumulative molecular response of 539 pts at 3, 6, 12, 18, and 24 mo after randomization is summarized in the Table: Month 3 6 12 18 24 BCR-ABLIS Achieved by % of pts ≤10% 41 66 81 85 86 ≤1% 16 41 65 76 78 ≤ 0.1% (MMR) 3 16 37 51 59 ≤0.01% 1 3 10 21 28 For analysis of prognostic impact, events were defined as (i) loss of complete hematologic response, (ii) loss of major CyR following loss of complete CyR, (iii) accelerated phase, (iv) blast crisis, and (v) death for any reason. Pts were censored at the time of allogeneic stem cell transplantation or switch to 2nd generation tyrosine kinase inhibitors because of imatinib intolerance or resistance. The minimum molecular response levels predictive for EFS were BCR-ABLIS of 10% after 6 mo (p=0.0029), 1% after 12 mo (p

In spite of favorable response and survival results for the majority of CML patients on imatinib therapy, in a substantial minority imatinib fails or shows suboptimal responses. A treatment optimization study was therefore designed to compare in a randomized fashion standard imatinib vs. imatinib + interferon alpha (IFN) vs. imatinib + low dose araC vs. imatinib after IFN (for low- and intermediate-risk patients) or vs. imatinib 800 mg (for high-risk patients). Inclusion criteria were newly diagnosed BCR/ABL positive CML in chronic phase. In July 2005, randomization to the arms imatinib + araC and imatinib after IFN was discontinued and recruitment for imatinib 800 mg was expanded to low- and intermediate-risk patients. Primary goals are: rates of hematologic, cytogenetic and molecular remissions, duration of chronic phase, overall survival, adverse events and analysis of subsequent allografting. Since its activation in 7/2002, 1203 patients have been randomized. The current evaluation represents the first of three designed, statistically adjusted interim analyses of 710 patients randomized by the end of 2005 with a followup of at least 2 years. Analysis was according to intention to treat. 666 patients (545 with primary imatinib, 121 with primary IFN) were evaluable for hematologic, 621 for cytogenetic, and 631 for molecular responses. Median age was 53 years, 60% were male, median values were for Hb 12.5 g/dl, WBC 71.2/nl and platelets 384/nl, 35% had low, 53% intermediate and 12% high risk (Euro score). Median observation time was 3.5 years. Median duration of IFN pretreatment was Figure Figure

The N-myc down-regulated gene 1 (NDRG1) is a stressed induced protein whose expression is associated with growth arrest and differentiation of tumor cells. Although the exact function of NDRG1 protein remains unknown, various studies support its role as a suppressor of tumor metastasis. In prostate, colon and breast cancer its expression is associated with a better disease prognosis and patient survival. In hematopoietic cells, NDRG1 was identified in a differential display screen for differentiation-related genes in human myelomonocytic U937 cells. In the present study, we sought to investigate the role of NDRG1 in myeloid differentiation. To this end we first evaluated NDRG1 mRNA expression in acute myeloid leukemia (AML; n=82) patient samples as well as in CD34+ progenitor cells (n=5) and neutrophils (n=6) of healthy donors using quantitative real-time RT-PCR. We found significantly higher NDRG1 mRNA levels in granulocytes as compared to CD34+ (p=0.0043) or AML blast cells (p Figure Figure

PU.1 is a hematopoietic transcriptional regulator that is necessary for the development of both myeloid and B cells. To identify new PU.1 target genes in neutrophil development PU.1 was introduced into mouse 503 PU.1-null cells using lentiviral gene transfer and microarray analyses of two independent 503 PU.1-rescued and parental 503 cells were compared. The BCL2A1 gene was found to be more than 50-fold induced in 503 PU.1- restored as compared to the parental 503-null cells. BCL2A1 (also known as BFL-1/A1) is an anti-apoptotic member of the BCL2 family. BCL2A1 was initially identified as a tissue-specific BCL2-related factor that is induced by different reagents such as granulocyte macrophage colony-stimulating factor (GM-CSF) or all-trans retinoic acid (ATRA) during myeloid differentiation. Upregulation of BCL2A1 in granulocytes may promote a time-dependent survival. To follow up on our microarray findings we evaluated loss of PU.1 function in human NB4 acute promyelocytic leukemia (APL) cells using lentivector delivered, short hairpin (sh) RNAs targeting PU.1. Knockdown efficacy upon ATRA-treatment in the two shPU.1 expressing NB4 cell lines was 67 and 30%, respectively. Silencing of PU.1 markedly reduced BCL2A1 mRNA induction upon ATRA-treatment from 167-fold in control cells to 47- and 112-fold in the two PU.1 knockdown NB4 cell lines, respectively (Figure A). Co-transfection of PU.1 with a human BCL2A1 promoter reporter resulted in a 7-fold activation, suggesting PU.1 can directly regulate BCL2A1. Co-transfection with NF-kappaB, used as positive control, induced the BCL2A1 promoter 14.5-fold. Moreover, in vivo binding of the transcription factor PU.1 to 2/8 putative PU.1 binding sites in the BCL2A1 promoter was shown by chromatin immunoprecipitation in HL60 promyelocytic cells further supporting a role for PU.1 regulation of BCL2A1. Evaluation of BCL2A1 and PU.1 mRNA expression in CD34+ hematopoietic progenitors, granulocytes, and primary acute myeloid leukemia (AML) cells was assessed using real-time quantitative RT-PCR. BCL2A1 and PU.1 mRNA levels were significantly lower in primary AML patient samples (n=80; p Figure Figure

Acute promyelocytic leukemia (APL) patients are currently treated with all-trans retinoic acid (ATRA) successfully resolving the differentiation block. However, concurrent chemotherapy is still necessary in combination with ATRA and novel less toxic therapeutic approaches are a major demand. Epigallocatechin-3-gallate (EGCG), the main polyphenolic compound present in green tea, has been reported to have chemopreventive and chemotherapeutic effects in different neoplasms. EGCG inhibits cell growth in vitro and in vivo and induces apoptosis in cancer cells without adversely affecting normal cells. Also, EGCG has been found in earlier studies to effectively kill AML blasts, but it has never been applied in combination with ATRA. We have previously shown that expression of the death-associated protein kinase 2 (DAPK2) enhanced ATRA-induced neutrophil development, and recently it was shown that EGCG specifically killed multiple myeloma cells while inducing DAPK2. Therefore, we first tested whether EGCG treatment induces DAPK2 expression in myeloid leukemic blast cells and whether this will lead to cell death. EGCG treatment of HL60 and NB4 acute myeloid leukemic cells led to a dose-dependent increase of DAPK2 mRNA with a maximum of 5.5- and 3.9-fold, respectively. In parallel, DAPK2 protein was markedly upregulated in both cell lines accompanied by a 72% increase of cell death after 24h, as measured by reduction of tetrazolium salt (XTT assay), and by hallmarks of apoptosis: activation of caspase-3 and phosphatidylserine exposure on the plasma membrane surface. EGCG-induced cytotoxicity was reduced by 48% in HL60 and by 46% in NB4 cells upon stable short hairpin RNA-mediated silencing of DAPK2. Moreover, combined ATRA and EGCG treatment of HL60 cells resulted in cooperative DAPK2 induction and potentiated myeloid differentiation as measured by CD11b and CD15 expression using flow cytometry (Figure A) as well as by C/EBPε and G-CSFR mRNA levels using quantitative RT-PCR. Enhanced differentiation was significantly reversed by knocking down DAPK2. Moreover, EGCG toxicity of NB4 and HL60 cells correlated with 67 kDa laminin receptor (67LR) protein expression which is downregulated during ATRA treatment of HL60 and NB4 cells but not in the ATRA-resistant sublines HL60-R and NB4-R. In line, HL60-R and NB4-R cells are still susceptible to EGCGinduced cell killing, whereas pretreatment of parental HL60 and NB4 cells with ATRA, causing downregulation of 67LR, rendered these cells resistant to EGCG mediated killing. Likewise, susceptibility of primary AML (n=8) samples to EGCG treatment was closely associated with 67LR expression. Moreover, neutrophils and PBMCs from healthy donors did not express 67LR and hence were resistant to EGCG treatment (Figure B). Figure Figure In summary, we found that DAPK2 is essential for EGCG-induced cell death in myeloid leukemic cells, and that a combination of ATRA and EGCG treatment significantly boosted neutrophil differentiation. This enhanced differentiation is most likely due to preferred EGCG-induced killing of ATRA-resistant leukemic cells expressing the EGCG receptor 67LR. We thus conclude that simultaneous ATRA and EGCG treatment might improve differentiation therapies for APL. In addition, other AML subtypes with high 67LR expression might also benefit from a combined chemotherapy and EGCG regimen.

Introduction Even mild renal dysfunction (e.g. creatinine 100 to 140 μmol/l) can be related to inadequate erythropoietin (EPO) response in patients with refractory anemia and bone marrow features compatible with dysplasia (Korte, Cogliatti et al. 2000). Overall, this seems not an infrequent mechanism (Fehr, Ammann et al. 2004) Therefore, patients with MDS bone marrow morphology and secondary bone marrow dysfunction due to EPO deficiency may be diagnosed as having a myelodysplatic syndrome (refracory anemia [RA] or even refractory anemia with ringed sideroblasts [RARS]). Patients and Methods We performed a single center, prospective, non-randomized pilot study to evaluate the potential benefit of EPO therapy in patients with refractory anemia, mild renal insufficiency and low EPO levels. Eligibility criteria were: hemoglobin (hb) concentrations Exclusion criteria were: active solid malignant tumors, evidence of chronic inflammatory disease, evidence of hemoglobinopathies or haemolytic anemia. Patients received EPO (epoetin beta, Recormon®) for 6 weeks with the aim to increase the hb concentrations to a steady state level of 120g/l. Epo was started at a fixed dose of 150 U/kg subcutaneously three times per week (tiw) and as soon as an improvement in hemoglobin was seen, the dose was reduced as needed to keep the hemoglobin at 120 g/l. With the targetd hb increase of 10 g/l, an estimated standard deviation of 5 g/l and alpha = 0.05 (power 80%), a statistically significant differences were expected with 4 patients treated. Results 5 patients were included in the study. One had a transient renal insufficiency, with excretory renal function normalizing during the study period, whereas the other four patients had persisting mild renal insufficiency. The patients received 150 U/kg tiw of epoetin beta for the first 4 weeks and all reached the target hb of 120g/l after this time (increase significant, p Discussion Our data indicate an excellent response to epoetin beta in patients with signs of myelodysplasia and mild renal insufficiency. The response rate (5/5, 100%) was much higher than described in other low risk MDS patients. Increasing levels of soluble sTfR reflect the improved erythropoietic activity and erythroid maturation. From these results, it can be speculated that anemia in low grade MDS with (even mild) renal insufficiency might in fact include aspects of renal anemia. EPO therapy seems an excellent treatment opportunity in anemic patients with marrow MDS morphology, renal dysfunction and low EPO levels. However, this observation and the question whether at least some of this myelodysplasias are direct consequences of inadequate erythropoietin levels warrant larger studies.

Targeted therapy with the BCR-ABL tyrosine kinase inhibitor imatinib induces high response rates in chronic myeloid leukemia (CML) patients (pts). Nevertheless, residual disease remains in virtually all pts on imatinib monotherapy as a potential cause of relapse. In July 2002, the German CML-Study Group activated the four-armed randomized controlled trial comparing imatinib 400mg/d with imatinib+IFN, imatinib+Ara-C, and imatinib after IFN failure in newly diagnosed pts with chronic phase CML. Randomization is stratified according to prognostic risk groups and not biased by consecutive allogeneic stem cell transplantation (SCT). High-risk pts are randomly assigned to primary imatinib-based therapies including a treatment arm with 800mg/d imatinib. By 7/05, 632 pts were randomized: imatinib 400mg/d (n=129), imatinib+IFN (n=179), imatinib+Ara-C (n=156), imatinib after IFN failure (n=157), and imatinib 800mg/d (n=11). According to the Hasford score, 35% of pts were low risk, 54% intermediate risk, and 11% high risk. At baseline, median WBC count was 67/nl (3–529), median platelet count 391/nl (34–2,799) and median hemoglobin 12.6 g/dl (6.1–16.6). We sought to evaluate results of pts with a >12 months follow-up (n=416), recruited between 7/02 and 6/04 (imatinib 400mg/d, n=102; imatinib+IFN, n=126; imatinib+Ara-C, n=104; imatinib after IFN failure, n=81; imatinib 800mg/d, n=3) and of pts with a >24 months follow-up (n=232), recruited between 7/02 and 6/03 (imatinib 400mg/d, n=55; imatinib+IFN, n=74; imatinib+Ara-C, n=54; imatinib after IFN failure, n=49) with respect to response, resistance, and progression. After 12 months of treatment cytogenetic data are available from 238/335 pts (71%) randomized to primary imatinib based therapies. 209 pts (63%) achieved a major cytogenetic remission (MCR; Ph+

DAPK2 is a 42-kDa Ca2+/Calmodulin-regulated serine/threonine kinase involved in apoptosis. In gene expression profiles derived from in vitro differentiated myeloid leukemic NB4 cells treated with all-trans retinoid acid (ATRA), we found that DAPK2 was decisively induced during differentiation towards neutrophils. DAPK1, a close relative of DAPK2, is inactivated in a number of hematopoietic malignancies (AML, lymphoma, myeloma), and it may play a role during normal and leukemic myeloid cell differentiation. We therefore investigated DAPK2 for its possible role in both normal and leukemic myelopoiesis. Real time quantitative RT-PCR (RQ-PCR) and Western blot analysis of DAPK2 gene expression in primary myeloid cells revealed significantly higher DAPK2 expression in granulocytes (G; n=9) compared with monocytes/macrophages (M; n=8) and CD34+ progenitor cells (CD34+; n=6) (Δ, p< 0.001; figure, left panel). Moreover, significantly increased DAPK2 mRNA levels were also seen when cord blood CD34+ progenitor cells were induced to differentiate towards neutrophils with human recombinant G-CSF (hrG-CSF). In addition, ATRA-induced neutrophil differentiation of two leukemic cell lines, NB4 and U937, showed significantly higher DAPK2 mRNA expression paralleled by DAPK2 protein induction. However, during differentiation of CD34+ cells (with hrM-CSF) and U937 cells (with PMA) towards monocytes/macrophages, DAPK2 mRNA levels remained low. DAPK2 expression in primary leukemic cells revealed significantly lower DAPK2 expression levels in AML blasts (AML; n=100) than in samples from chronic myeloid leukemia patients in chronic phase (CML-CP; n=9) (ΔΔ, p< 0.001; figure, right panel). Figure Figure Stable lentiviral-mediated expression of wild-type DAPK2 enhanced ATRA-induced granulocytic differentiation of NB4 cells as shown by morphology and by increased CD11b expression. Furthermore, upregulation of mRNA levels of key regulator genes for terminal differentiation, such as C/EBPe, the G-CSF receptor and the secondary granule protein lactoferrin, was also enhanced. Expression of a kinase-inactive DAPK2 mutant did not show these effects, a finding consistent with a role of DAPK2 in granulopoiesis. Conclusion: we demonstrate for the first time, that DAPK2 expression levels correlate with the degree of granulocytic differentiation, and that DAPK2 upregulation is restricted to granulopoiesis. Furthermore lentiviral-mediated DAPK2 expression enhances granulocytic differentiation. The finding that DAPK2 expression is low in AML and high in CML-CP patients suggests that suppressed DAPK2 expression may contribute to the differentiation block in AML.

In chronic myeloid leukemia (CML), imatinib may reverse bone marrow fibrosis (MF) that has occurred before start of therapy. The risk and prognostic relevance of MF evolving during imatinib treatment are unclear as yet. Bone marrow biopsies (n = 1509) taken prospectively from Ph+ CML patients (n = 605) were examined for MF before and during therapy. 107 patients were treated with 400 mg imatinib / day, 208 with interferon-alpha +/− cytosine arabinoside, 154 with hydroxyurea and 136 with busulfan. Imatinib and interferon-alpha +/− cytosine arabinoside were significantly more effective than the other types of therapy regarding reversal of initial MF (P < 0.000005). During the follow-up period of 3 years, imatinib monotherapy was not superior to interferon-alpha or hydroxyurea in preventing evolution of MF: MF affected more than 20 % of patients and developed from small foci with increased fiber deposition to full-stage fibrosis within 1 – 2 years. Hematologic, cytogenetic and molecular response did not protect against evolution of MF as long as a complete molecular remission (i.e. bcr/abl negativity) was not achieved. Evolving MF was an independent significant predictor of therapy resistance and shortened survival time of patients irrespective of the type of treatment (P < 0.00005). Conclusion: Although imatinib reverses initial MF in CML, MF may evolve during imatinib monotherapy indicating an unfavorable course of disease independent of hematologic, cytogenetic and molecular response.

The advent of imatinib has considerably changed treatment in chronic myeloid leukemia (CML). Although response rate and duration of response with imatinib monotherapy continue to be impressive, the majority of patients (pts) in complete cytogenetic remission (CCR) retain BCR-ABL transcripts as markers of residual disease and potential cause of relapse. In addition rapid evolvement of blast crises from CCR has been reported. Therefore, we designed an investigator-initiated phase IV prospective trial aiming to address the role of imatinib in combination with interferon alpha (IFN) or Ara-C and treatment intensification with high dose imatinib. In July 2002, the German CML-Study Group has activated the four-armed randomized controlled trial comparing imatinib 400 mg/d with imatinib+IFN, imatinib+Ara-C and imatinib after IFN failure in newly diagnosed pts with chronic phase CML. Randomization is stratified according to prognostic risk groups and not biased by consecutive allogeneic stem cell transplantation (SCT). High risk pts are randomly assigned to primary imatinib-based therapies including a 4th treatment arm with imatinib 800 mg/d. The treatment arm imatinib after IFN failure retains the chance of an IFN-induced CCR with 10 year-survival rates of 70–80%. In case of IFN failure pts are crossed over to imatinib. Allogeneic SCT is recommended for all pts with high risk, imatinib failure and EBMT-score 0–1. By August 2004, 429 pts were randomized: imatinib 400 mg/d (n=103), imatinib+IFN (n=130), imatinib+Ara-C (n=108), imatinib after IFN failure (n=84), and imatinib 800 mg/d (n=4). According to the New CML score, 34% of patients were low risk, 56% intermediate risk, and 10% high risk. At baseline, median WBC count was 63/nl (3.5–513), median platelet count was 385/nl (49–2,799) and median hemoglobin was 12.7 g/dl (6.1–16.6). We sought to evaluate results of the first cohort of pts (n=217) with a >12 months follow-up, recruited between 7/2002 and 5/2003 (imatinib 400 mg/d, n=52; imatinib+IFN, n=70; imatinib+Ara-C, n=49; imatinib after IFN failure, n=46). Median age was 56 yrs (16–82), 62% of pts were male. Cytogenetic data are available from 117 pts (68%) randomized to primary imatinib-based therapies. At 12 months, 104 pts (89%) achieved a major cytogenetic remission (Ph+