Peripheral Blood Blast Percentage Research Articles

Low JAK2V617F allele burden in primary myelofibrosis, compared to either a higher allele burden or unmutated status, is associated with inferior overall and leukemia-free survival

The clinical relevance of JAK2V617F allele burden in primary myelofibrosis (PMF) has not been previously studied. Bone marrow-derived DNA from 199 patients with PMF was subjected to qualitative (n=199) and quantitative (n=129) analysis for V617F. Mutational frequency was 58% and median mutant allele burden ratio in V617F-positive patients was 29% (range, 1-74%). Multivariable analysis identified older age, platelet count > or =100 x 10(9) l(-1) and peripheral blood blast percentage <3% as being associated with a positive mutational status. The mere presence of the mutation did not affect the incidence of thrombosis (P=0.78), overall survival (P=0.22) or leukemia-free survival (P=0.5). The 129 patients with allele burden information were divided into four groups: V617F-negative (n=53) and V617F-positive with mutant allele burden in the lower quartile (n=19), middle quartiles (n=38) or upper quartile (n=19) range. Kaplan-Meier plots revealed significantly shortened overall (P=0.0008) and leukemia-free (P=0.01) survival for the lower quartile, but not for upper quartile allele burden group; independent prognostic relevance was validated by multivariable analysis. We conclude that low V617F allele burden in PMF might indicate the presence of an overriding V617F-negative clone that confers a more aggressive disease phenotype.

High expression of ERCC1, FLT1, NME4 and PCNA associated with poor prognosis and advanced stages in myelodysplastic syndrome

Myelodysplastic syndrome (MDS) represents a good model for research of prognostic/progression markers due to frequent transformation into acute myeloid leukemia (AML). We analysed expression profiles of 26 MDS and 6 AML patients using cDNA arrays comprising 588 gene probes. The array data were validated in a larger set of 46 patients by qRT-PCR. Data analysis identified differently expressed genes in MDS and the cluster of four genes (ERCC1, FLT1, NME4 and PCNA) whose expression was correlated with MDS subtypes. High expression of these genes was associated with poor prognosis and/or unfavorable outcome. Furthermore, PCNA expression was correlated with peripheral blood blast percentage (r = 0.71, p < 0.05), while the other genes showed non-significant correlation. Our findings demonstrate the progressive up-regulation of the genes along the sequence of 5q-syndrome/RCMD/RAEB/de novo AML, suggesting their association with disease progression.

Neuropilin-1 in acute myeloid leukemia: Expression and role in proliferation and migration of leukemia cells

Neuropilin-1 (NRP-1) is a novel receptor of vascular endothelial growth factor (VEGF) and expressed in endothelial cells and tumor cells. The role of NRP-1 in the growth and progression of leukemia is unknown. Here we studied the mRNA expression and effect of NRP-1 in leukemic cells. Our results showed that NRP-1 mRNA was expressed in six of seven leukemic cell lines and primary leukemias derived from all 24 patients with acute myeloid leukemia (AML). Reduced NRP-1 expression by RNA interference led to a decrease of VEGF-mediated mitogenic and migration responses in acute myeloid leukemic cell line HEL. Increased NRP-1 expression was directly correlated with the blast percentage in both peripheral blood and bone marrow of AML patients. Our data demonstrated that a higher level of NRP-1 mRNA was expressed in leukemias and NRP-1 promoted proliferation and chemotaxis of leukemic cells in response to VEGF. Inhibition of NRP-1 functions may provide a new therapeutic strategy for treatment of AML.

Clinical Evolution to Primary Myelofibrosis - Blast Phase: An International Working Group for Myelofibrosis Research and Treatment (IWG-MRT) Collaborative Retrospective Analysis.

Background: We sought to retrospectively analyze the clinical differences, at diagnosis and throughout the disease course, between patients with primary myeloifbrosis whom undergo blastic transformation (PMF-BP) and those whom expire from PMF complications without undergoing transformation.Methods: An international collaborative database of patients with PMF which progressed to PMF BP, and a control group of individuals with PMF who expired secondary to PMF was created. Data regarding clinical course, bone marrow, karyotypic, quantitative JAK2V617F analysis (when able), laboratory values, and therapy at the diagnosis of PMF, PMF BP and up to 4 return visits (R1-4) in between these milestones was abstracted.Results: COMPARISON AT DIAGNOSIS OF PMF: 136 cases of PMF who eventually underwent PMF-BP were included, with a control group of 42 PMF patients, were analyzed. Both groups of patients had similar demographic (median age at diagnosis 59 years (range 23–83)/ 59.1 (15–93); and disease parameters (median hemoglobin 10 g/dL (range 2–15.7) /9.8 (4.9–14.6); median platelet count 181 x 109/L (range 7–1400)/168 (16–1916)), and Lille PMF prognostic scores (p = n.s.) for PMF-BP vs. PMF control group respectively. Additionally, blasts (peripheral blood /marrow) were a median of 0% (range 0–18%)/ 2% (range 0–16%) for the study group versus 0.25% (range 0–5%)/ 3% (range 0–4%) (p = n.s. for both) for the control group, respectively. Both groups had similar rates of requiring therapy (86%; 93%) and survival from diagnosis (median 34 months (range 2–441); 29 months (1–236)) (p = n.s.). However, lactate dehydrogenase (LDH) (although high in both groups) was higher at diagnosis (median 802 IU/L (range 83–10353) vs. 416 IU/L (124–2197)) (p=0.04), as well as an abnormal marrow karyotype (85% vs. 25%; p<0.001) amongst the PMF BP group.SUBSEQUENT CLINICAL COURSE: Analyzing the clinical evolution between groups demonstrated persistently higher LDH and worsening thrombocytopenia in the PMF-BP cohort (see figure). [Display omitted] Peripheral blood blasts increased in both groups, but values above 10% were unique to the PMF BP group. Additionally marrow karyotype displayed clonal evolution developed in 56% of the PMF-BP patients as opposed to 14% of controls (p<0.001). Initial and serial quantitative JAK2V617F mutation analysis (available from 20 /19 patients from the PMF-BP and control group at diagnosis, with 11 / 12 serial samples) showed no difference between the groups, nor a pattern of mutation burden elevation with transformation to leukemia in the study group.Conclusions: Increasing LDH, peripheral blood blast percentages >10%, and clonal evolution are features commonly seen in PMF patients whom evolve to blast phase and may be a harbinger of movement towards PMF BP.

Low JAK2V617F Allele Burden in Primary Myelofibrosis, Compared to Either a Higher Allele Burden or Unmutated Status, Predicts Inferior Overall and Leukemia-Free Survival.

Background : Two previous studies have reported significant but inconsistent associations between the presence of JAK2V617F in primary myelofibrosis (PMF) and older age at diagnosis, risk of thrombosis, higher leukocyte count, and inferior survival (Tefferi, et al. BJH 2005; 131:320, Campbell, et al. Blood 2006; 107:2098). The clinical relevance of V617F allele burden in PMF has not been previously studied.Methods : Diagnosis of PMF was based on the World Health Organization criteria and study eligibility included the availability of bone marrow-derived DNA that was collected either at time of diagnosis or within one year of diagnosis. Quantitative allele specific PCR was utilized to meaure V617F allele burden.Results I. V617F-positive vs. V617F-negative comparisons: A total of 199 patients (60% males; median age 61 years) were suitable for analysis of comparisons between mutation-positive and mutation-negative disease. The Dupriez prognostic scoring system (PSS) risk distributions were 61% low-risk, 31% intermediate-risk, and 8% high-risk. Hypercatabolic symptoms were present in 27% of the patients and ≥1% peripheral blood (PB) blasts in 37%. At a median follow-up of 23 months (range 0–266), 57 patients (29%) had died, 17 (9%) developed leukemic transformation (LT) and 10 (5%) experienced major thrombosis. V617F mutational frequency was 58%. Univariate analysis identified older age (p=0.0007), platelet count ≥ 100 x 109/L (p=0.05), and PB blast percentage < 3% (p=0.001) as being associated with a positive mutational status; all three variables sustained their significance during multivariable analysis. The presence of the mutation did not affect the incidence of thrombosis (p=0.78), overall survival (p=0.22) or leukemia-free survival (p=0.5).Results II. Clinical correlates of V617F allele burden: Quantitative measurement of V617F allele burden was performed in 129 patients that were divided into four groups: V617F-negative (n=53) and V617F-positive with mutant allele burden in the lower quartile (n=19), middle quartiles (n=38), or upper quartile (n=19) range (median and range of V617F allele burden ratio was 29% and 1% to 74%). Kaplan-Meier plots revealed significantly shortened overall (Figure; p = 0.0008) and leukemia-free (p = 0.01) survival for the lower quartile allele burden group; survival significance was sustained in a multivariable analysis that included the Dupriez PSS. Lower quartile allele burden was also associated with lower leukocyte count (p = 0.003) and presence of hypercatabolic symptoms (p=0.05). Thrombosis incidence was not affected by allele burden.Conclusions: In PMF, patients with a low V617F allele burden, compared to those with either undetectable (i.e. wild-type) or higher allele burden, display significantly shorter overall and leukemia-free survival. In contrast, the presence or absence of the mutation, by itself, does not result in distinct groups that differ significantly in terms of survival, LT, or incidence of thrombosis. These data suggest that a low V617F allele burden in PMF is a surrogate for the development of dominant V617F-negative subclones that are more likely to undergo LT. [Display omitted]

Erythropoiesis Stimulating Agents and the Risk of Leukemic Transformation in Primary Myelofibrosis.

BACKGROUND: Information regarding risk factors for leukemic transformation (LT) in primary myelofibrosis (PMF) is limited, although both leukocytosis and abnormal cytogenetics have previously been implicated. The current retrospective study examines clinical variables at diagnosis as well as specific treatment modalities for their effect on LT in PMF.METHODS: Diagnoses of PMF and LT were based on World Health Organization criteria. In addition, study inclusion required availability, for review, of bone marrow histology and clinical data obtained at or within 6 months of diagnosis but prior to treatment intervention. Statistical methods used were standard and included Cox regression analysis of leukemia-free survival (LFS).RESULTS: A master database of PMF patients seen at the Mayo Clinic from 1976 through 2006 was queried to identify 311 patients who fulfilled the aforementioned stipulated criteria for study inclusion; median age was 57 years and 41% were females. At presentation, 30% of the patients displayed a hemoglobin level (Hgb) of < 100 g/L, 20% a leukocyte count of < 4 or > 30 x 109/L, 18% a platelet count of < 100 x 109/L, 12% an absolute monocyte count (AMC) of ≥ 1 x 109/L, 28% hypercatabolic symptoms and 35% a peripheral blood (PB) blast percentage of ≥ 1; 27 patients (9%) had a PB blast percentage of ≥ 3. Dupriez prognostic scoring system distribution for high, intermediate, and low risk disease was 30 (10%), 94 (30%), and 187 (60%) patients. Among 182 and 139 evaluable patients, 74 (41%) and 80 (58%) displayed cytogenetic abnormalities and JAK2V617F, respectively. At a median follow-up of 27 months (range 0–282), 27 cases (9%) of LT were documented at a median time from diagnosis to LT of 26 months (range 0.8–266). Effect of clinical and laboratory variables at diagnosis on leukemic transformation By univariate analysis, LFS was negatively affected by anemia (p=0.04), leukocytosis (p=0.04), PB monocyte count ≥ 1 x 109/L (p=0.02), platelet count of < 100 x 109/L (p=0.004), hypercatabolic symptoms (p=0.03) and PB blast percentage of ≥ 3 (p<0.0001); LFS was not affected by PB blast percentage of > 1 but < 3 (p=0.49). By multivariable analysis, significance was sustained only for PB blast percentage of ≥ 3 (p = 0.0002) and platelet count of < 100 x 109/L (p = 0.02) with hazard ratios (HR) of 5.8 and 2.8 and 95% confidence intervals (CI) of 2.3–14.6 and 1.2–6.6, respectively. The presence of JAK2V617F did not affect LFS (p=0.98). Effect of specific treatment on leukemic transformation By univariate analysis, LT was significantly associated with history of splenectomy (p=0.01) and treatment with erythropoiesis stimulating agents (ESA; p=0.004), danazol (p=0.007), and androgens (p=0.03) but not with hydroxyurea (p=0.17), interferon alpha (p=0.95), thalidomide (p=0.26) or other drugs. On multivariable analysis, significance was sustained for both ESA (p = 0.005; HR 3.1, CI 1.4–6.8) and danazol (p = 0.01; HR 3.4, CI 1.3–8.5), even when the aforementioned prognostic indicators at diagnosis were added as covariates to the multivariable model.CONCLUSIONS: The current study identifies PB blast percentage of ≥ 3% and platelet count of < 100 x 109/L, at presentation, as independent risk factors for LT in PMF. Unexpectedly, the study also revealed an association between LT and treatment history with ESA or danazol. These observations are intriguing, considering recent reports on the possible harmful effects of ESA in certain solid tumors.

Megakaryocytic Blast Phase (M-BP) of Chronic Myelogenous Leukemia (CML).

Approximately 65% of patients with CMP BP exhibit a myeloid phenotype, 30% a lymphoid, and 5% of cases have and undifferentiated or mixed phenotype. Only anecdotal cases of BP with megakaryocytic differentiation (M-BP) have been reported. To evaluate the incidence and outcome of M-BP, we reviewed 410 patients with CML who underwent transformation to BP at M.D. Anderson Cancer Center between January 1999 and April 2007. Three cases (2 female) were diagnosed as having M-BP (incidence 0.7%). The median age was 50 years (range, 49–74). Two patients were initially diagnosed with chronic phase (CP) CML while 1 presented initially with M-BP. The median time from CML diagnosis to M-BP transformation was 76 months (range, 0–101). At the time of transformation, 2 patients presented with >20% bone marrow (BM) blasts whereas 1 other had only 2% blasts but developed extensive subcutaneous granulocytic sarcomas. The median white blood cell count at the time of transformation was 41.4x109/L (range, 39–44.7), hemoglobin 10.6 g/dL (range, 9.6–10.9), platelet count 270x109/L (range, 22–383), peripheral blood (PB) blast percentage 9% (range, 1–20), BM blast percentage 32% (range, 2–65). Flow cytometry analysis in BM blasts demonstrated positivity for markers of myeloid lineage (CD11c, CD13, CD33) as well as CD41 in all 3 patients. All patients expressed p210 BCR-ABL1 transcripts (b3a2 in 2 cases, b2a2 in 1). Initial therapy for M-BP in 1 patients consisted of troxacitabine (with no response), followed by imatinib 400 mg/d, which rendered a complete cytogenetic response (CCyR) for 35 months. The patient then received nilotinib at 600 mg twice daily with no response and died 7 months later. A second patient received imatinib 600 mg/d, ara-C 10 mg/d subcutaneous, and idarubicin 12 mg/m2 intravenous every 14 days, achieving a CCyR for 28 months. The patient relapsed in accelerated phase based on clonal evolution (i(17), −7,−18, and double Philadelphia chromosome). Therapy with dasatinib 140 mg/d was started, resulting in a brief CCyR (4 months) but prolonged (20 months) complete hematologic response (CHR), during which a F317L mutation was detected that resulted in loss of CHR. This patient is currently on hydroxyurea 59 months after diagnosis of M-BP. The third patient, who presented with a subcutaneous granulocytic sarcoma, achieved a brief CHR on dasatinib 50 mg twice daily. Dasatinib therapy was interrupted due to pericardial tamponade. While off therapy, the patient developed wide-spread granulocytic sarcomas of the skin, subcutaneous tissue, and right orbit, as well as 30% blasts in BM. DNA expansion of specific clones followed by DNA sequencing detected the dasatinib-resistant mutation V299L in 30% of clones. Therapy with dasatinib was ineffective and the patient died after 14 months in M-BP. In conclusion, M-BP is an extremely rare subtype of BP CML and exhibits resistance to conventional BCR-ABL kinase inhibitor therapy. Although prolonged responses can be achieved with these agents, more effective therapies are warranted.

Characterisation and Prognostic Significance of WT-1 Gene Expression in Acute Myeloid Leukemia (AML).

Background: Wilms' tumour gene 1 (WT-1) is frequently over-expressed in adult AML and may be of prognostic value. We examined the prognostic utility of WT-1 expression in the peripheral blood, measured by RQ-PCR on diagnostic specimens, and characterised this compared to other clinical and biological predictors of survival.Methods: RQ-PCR was performed in triplicate on samples from newly diagnosed AML patients, using the Corbett Rotorgene 3000. Values were averaged and levels expressed relative to 104 ABL copies. Multivariate stratified Cox regression, with the stratification variable cytogenetic risk group and WT-1 levels analysed as a continuous variable, was used to model the outcomes of overall survival (OS) and event free survival (EFS).Results: Samples were collected from 58 patients with AML. The median age was 66 years (range 16–82) and 30 were male. Seven had antecedent haematological disorders and 9 had received prior chemo/radiotherapy. Induction therapy was with cytarabine based regimens in 18, high dose cytarabine regimens in 20, ATRA/chemotherapy in 6 and supportive care in 14. Complete remission was achieved in 64% with 18% induction mortality. Median OS was 4 months (17 months in responders) and 27% at 2 years. The median WT-1 transcript level in diagnostic AML samples was 5122 (range 9–36125), while in normal control samples it was 3 (n=11, mean 3.6, SD 1.6).In multivariate Cox regression, stratified by cytogenetic risk group, age (p<0.001), LDH (p<0.001) and performance status (p=0.04) retained prognostic significance for OS and EFS. Elevated peripheral blood WT1 levels were significantly associated with impaired OS (HR 1.24 per log10 transcript levels p=0.022) and EFS (HR 1.31 per log10 transcript levels p=0.0019). WT1 levels correlated with cytogenetic risk group (p=0.002 with higher levels seen in the favourable risk group), antecedent haematological disorder (p=0.05), peripheral blood blast percentage (p=0.05) and bone marrow blast percentage (p=0.01). WT1 levels were significantly higher in acute promyelocytic leukaemia (p=0.0001) compared to other AML subtypes. WT1 levels did not correlate with age (p=0.16), sex (p=0.12), prior chemo/radiotherapy (p=0.96), performance status (p=0.33) or LDH (p=0.91).Conclusions: WT1 RQ-PCR levels are frequently elevated in peripheral blood from patients with AML at diagnosis and are associated with subtype, cytogenetic risk group, blast percentage and antecedent haematological disorder. Within specified cytogenetic risk groups, elevated WT1 levels may predict AML patients at high risk of relapse and subsequent mortality.

Phase I Study of Flavopiridol in Combination with Imatinib Mesylate (STI571, Gleevec) in Bcr/Abl+ Hematological Malignancies.

Imatinib (Im), a rationally designed inhibitor of the Bcr/Abl kinase as well as other kinases, represents the standard treatment for Bcr/Abl+ malignancies. Im as a single agent, however, is not curative. Flavopiridol (Fl), an investigational cyclin dependent kinase inhibitor, is broadly active in vitro against human leukemia cells (Blood 91:2482, 1998). Previously we have shown that simultaneous disruption of a survival signaling pathway and a cell cycle regulatory pathway results in a pronounced increase in leukemic cell death (Cancer Res. 61:5106, 2001) and in more recent preclinical studies demonstrated synergistic interactions between Im and Fl in Bcr/Abl+ leukemia cells, including some that were resistant to Im (Clin Cancer Res 8;2976, 2002). Based on these considerations, we have initiated a phase I trial to identify appropriate doses of Im+Fl for further investigation. Eligible patients (pts) have CML with a suboptimal response to prior Im, CML in blast crisis, or Bcr/Abl+ acute lymphocytic leukemia (ALL). CML-BC and ALL patients may be Im-naïve. Pts receive Im by continuous daily oral dosing and Fl by 1 hour intravenous infusion weekly x 3 repeated every 4 weeks. Targeted dose levels are (Fl/Im; mg/m2): 30/400, 30/600, 45/600, 60/600, 60/800, 60/1000. Patients are divided into 2 strata based upon blast percentage in peripheral blood or bone marrow: stratum 1, <15%; and stratum 2, ≥15%. For stratum 1 dose limiting toxicity (DLT) is defined as NCI CTCAE grade 4 ANC/platelet for > 1 week or grade ≥ 3 non-heme toxicity; for stratum 2, DLT is profound marrow hypoplasia in the absence of persistent leukemia. In stratum 1, 16 pts have been treated at 4 dose levels; in stratum 2, 5 pts in the 1st and 3rd dose level. In stratum 1, 1 DLT has occurred at dose level 4 (cholecystitis requiring cholecystectomy); in stratum 2, 1 DLT has occurred at dose level 3 (sepsis/multi-organ failure which was not clearly related to treatment). The only frequent toxicities have been hematological. 4 pts have experienced objective responses including complete hematological remissions in 2 pts in stratum 1 treated with Im/Fl 30/600 who had been previously treated with Im 800 and complete hematological remissions in 2 pts in stratum 2 (who had not received prior Im). Preliminary studies indicate no Fl impact upon Im pharmacokinetics, and variable post-treatment effects on signaling pathways in CML cells. These findings indicate that a regimen consisting of Fl and Im is tolerable and active in at least some patients with Bcr/Abl+ hematologic malignancies, including some with Im-resistant disease. Pending identification of the MTD and the recommended Phase II dose (RPTD), Phase II trials will be necessary to assess the activity of this strategy more definitively.

Having a higher blast percentage in circulation than bone marrow: clinical implications in myelodysplastic syndrome and acute lymphoid and myeloid leukemias

Determining the percentage of peripheral blood (PB) and bone marrow (BM) blasts is important for diagnosing and classifying acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS). Although most patients with acute leukemia or MDS have a higher percentage of BM blasts than PB blasts, the relative proportion is reversed in some patients. We explored the clinical relevance of this phenomenon in MDS (n = 446), AML (n = 1314), and acute lymphoblastic leukemia (ALL) (n = 385). Among patients with MDS or ALL, but not AML, having a higher blast percentage in PB than in BM was associated with significantly shorter survival. In multivariate analyses, these associations were independent of other relevant predictors, including cytogenetic status. Our findings suggest that MDS and ALL patients who have a higher percentage of PB blasts than BM blasts have more aggressive disease. These data also suggest that MDS classification schemes should take into account the percentage of blasts in PB differently from the percentage of blasts in BM.

Identification of various MLL gene aberrations that lead to MLL gene mutation in patients with acute lymphoblastic leukemia (ALL) and infants with acute leukemia

Studies were done to investigate MLL gene aberrations using Conventional Cytogenetics, Southern blotting as well as FISH using a panel of probes on 218 cases which included 206 cases of pediatric/young adult ALL and 12 cases of infantile acute leukemias from Tata Memorial Hospital, India. The incidence of MLL gene rearrangements in acute lymphoblastic leukemia (ALL) was 9.4% which included infants as well as pediatric/young adults. In infantile group which included ALL as well as AML cases, MLL gene rearrangement was very common (75% frequency). Application of metaphase-FISH helped unravel MLL rearrangements not only as a result of translocations but also inversions, insertions, partial deletion, duplications, partial duplication→self-fusion. Besides age, MLL gene rearrangements showed significant association with hyperleukocytosis, peripheral blood blast percentage and early Pre-B phenotype. Clinical outcome of patients with MLL gene rearrangements revealed unfavorable prognosis.

Peripheral blood CD34 count in myelofibrosis with myeloid metaplasia: a prospective evaluation of prognostic value in 94 patients

In a prospective study, peripheral blood (PB) CD34 count, bone marrow histology and other clinical parameters were concurrently evaluated in 94 patients with myelofibrosis with myeloid metaplasia (MMM) and the study cohort followed for a minimum of 3 years. Median PB CD34 count was 0.0547 x 10(9)/l (range 0-5.345 x 10(9)/l) with 86% of the patients displaying above normal levels (>0.005 x 10(9)/l). In a multivariate analysis, only leucocyte count and PB blast percentage correlated with PB CD34 count in an independent and consistent fashion. After a median follow up of 41 months from PB CD34 analysis, 43 patients (46%) have died with a projected 5-year survival of 50%. In a univariate analysis, PB CD34 count above 0.1 x 10(9)/l correlated significantly with shortened survival, leukaemic transformation and clinical progression. However, such statistical significance was lost during multivariate analysis, which identified only anaemia and leucocytosis as independent risk factors for shortened survival. Furthermore, sequential analysis of PB CD34 count was performed in 53 patients and 43% of those who progressed clinically did not display a concomitant rise in their PB CD34 count. The current prospective study does not support an independent prognostic value for PB CD34 count in MMM.

Circulating and Local Bone Marrow Renin-angiotensin System in Leukemic Hematopoiesis: Preliminary Evidences

Until last the decade, the renin-angiotensin system (RAS) was considered as a circulating endocrine system. It is now known that there are local RASs in many tissues. It has also recently been hypothesized that there exists a local bone marrow (BM) RAS with paracrine/autocrine pathobiological functions. The aim of this study was to detect BM and peripheral blood levels of the essential RAS components in normal and leukemic hematopoiesis.Concentrations of renin and angiotensin-converting enzyme (ACE) were assayed in BM aspirates and in simultaneously drawn peripheral blood samples of 16 pre-chemotherapy leukemic and 10 post-treatment megaloblastic anemia patients with normal blood counts, as controls.In the leukemia group, the ACE concentration was found to be significantly higher in the BM (38±6.2 U/l) than in the peripheral blood (29.5±5.3 U/l), (p=0.029). In the leukemia group, although the BM renin concentration was higher than the peripheral blood levels (21.3±8.3 vs. 18.6±6.2 U/l), this difference was not statistically significant (p=0.196). In the control group, mean BM renin levels were insignificantly lower than in the peripheral blood (8.6±3 vs. 12.1±4.6 pg/ml) (p=0.059). In the leukemia group, serum ACE levels positively correlated with BM and peripheral blood blast percentages (p<0.05). Serum LDH level (p<0.01), BM blast (p<0.05) and peripheral blast percentages (p<0.01) were inversely correlated with serum potassium in the leukemia group.The results of this study can be considered as the preliminary evidence supporting the hypothesis of the presence of a local BM RAS. Further, molecular biologic and immunohistochemical studies are needed to shed light on this important subject. A better understanding of the interrelationships of RAS and hematopoiesis will bring new insights into the pathobiology and even novel therapies for such neoplastic diseases.

Mode of disease progression in primary myelodysplastic syndromes: A Japanese co-operative study

Chronological changes in hematological findings were analyzed in 225 patients with myelodysplastic syndromes (MDS). They were diagnosed between 1990 and 1992. Their hematological findings, i.e. hemoglobin levels, leukocyte and platelet counts, proportions of peripheral blood (PB) blasts and monocytes, and proportion of blasts in bone marrow (BM), were recorded for up to 42 months after diagnosis, when available. BM was examined regularly in only a few patients. Therefore, it was impractical to use the French-American-British Cooperative Group criteria for subtype classification during the disease course. Thus, we used the percentage of PB blasts as the only indicator of stage evolution. We classified the disease into four stages: stage 1, less than 1% PB blasts; stage 2, 1–5% PB blasts; stage 3, 5–30% PB blasts; and stage 4, 30% or more PB blasts. There were 171 patients initially in stage 1, 37 initially in stage 2, and 17 initially in stage 3. Less than half (45%) of the patients initially in stage 1 progressed to stage 2, while 91% of the patients initially in stage 2 and all of the patients initially in stage 3 showed stage evolution. Eight variables, i.e. BM blasts 5% or more, male sex, karyotypic abnormalities, micromegakaryocytes, mononuclear large megakaryocytes, platelet counts 50 × 10 9/l or higher, abnormal nucleus of granulocytes, and abnormal granules of granulocytes, were found to be significant risk factors for evolution from stage 1 to 2. Evolution from stage 1 to a higher stage within 15 months of diagnosis was associated with impending poor prognosis in most patients. However, of the 67 patients initially in stage 1 who died, 30 did not show stage evolution. Evolution from stage 2 to a higher stage and from stage 3 to stage 4 was also associated with impending poor prognosis. Higher levels of cytopenia were not associated with poorer prognosis in the stage 1 patients. In conclusion, our grading system proved to be useful in evaluating the chronological changes in MDS patients.