Myelogenous Leukemia In Blast Phase Research Articles

Molecular characterization of de novo Philadelphia chromosome-positive acute myeloid leukemia

Philadelphia chromosome-positive (Ph+) acute myeloid leukemia (AML) is a controversial diagnosis, as others propose that it represents chronic myelogenous leukemia in blast phase (CML-BP). NPM1 mutations occur in 25–35% of patients with AML but are absent in patients with CML. Conversely, ABL1 mutations occur in 25% of imatinib-naive patients with CML-BP but are not described in patients with AML. We analyzed for NPM1 and ABL1 mutations in nine Ph+ patients with AML and five patients with CML-BP initially presenting in BP. In six cases of Ph+ AML, we screened for a panel of gene mutations using Sequenome®-based methods including AKT1, AKT2, AKT3, BRAF, EGFR, GNAQ, GNAS, IDH1, IDH2, KRAS, MET, NRAS, PIK3CA and RET. Two of nine (22%) patients with Ph+ AML had NPM1 mutations and were alive 36 and 71 months after diagnosis. All cases of Ph+ AML were negative for ABL1 and other gene mutations. One (20%) patient with CML-BP had ABL1 mutation; no patients had NPM1 mutations. These data suggest that Ph+ AML is distinct from CML-BP.

Imatinib-resistant lymphoid clone of chronic myelogenous leukemia in blast phase arising from B cell-committed progenitor leukemic stem cells

Imatinib-resistant lymphoid clone of chronic myelogenous leukemia in blast phase arising from B cell-committed progenitor leukemic stem cells

Long‐term experience with imatinib therapy in chronic phase chronic myelogenous leukemia—Remarkable activity with room for improvement

Long‐term experience with imatinib therapy in chronic phase chronic myelogenous leukemia—Remarkable activity with room for improvement

Outcomes among Patients with Recurrent High-Risk Hematologic Malignancies after Allogeneic Hematopoietic Cell Transplantation

We retrospectively analyzed outcomes among 307 consecutive patients who had recurrent or persistent acute leukemia (n = 244), chronic myelogenous leukemia in blast phase (CML; n = 28), or advanced myelodysplastic syndromes (MDS; n = 35) after allogeneic hematopoietic cell transplantation and who received at least 1 relapse-directed intervention: withdrawal of immunosuppression, chemotherapy, or donor lymphocyte infusion (DLI). Transplants were performed at a single institution between 1995 and 2004, and outcomes were analyzed according to time intervals from transplantation to detection of malignancy: “early,” <100 days (n = 111); “intermediate,” 100-200 days (n = 73); and “late,” >200 days (n = 123). The overall remission rate was 30%. Compared to early recurrence, intermediate recurrence and late recurrence were associated with increasing probabilities of remission (hazard ratios, 1.89 and 2.16; P = .05 and .02) and decreasing risks of overall mortality (hazard ratios, 0.73 and 0.33; P = .05 and <.0001). The 2-year overall survival (OS) estimates for patients with early, intermediate, and late recurrence were 3%, 9%, and 19%, respectively. Remission was associated with a median survival prolongation of 9.5 months. Individual types or combinations of these nonrandomly assigned relapse-directed interventions were not associated with higher or lower probabilities of remission or survival. More effective intervention strategies are needed for treatment of recurrent high-risk hematologic malignancies after hematopoietic cell transplantation. In the absence of innovative clinical trials, patients with early recurrence might wish to forego further interventions in favor of palliative care.

Use of Imatinib Mesylate for Favorable Control of Hypercalcemia Mediated by Parathyroid Hormone-Related Protein in a Patient with Chronic Myelogenous Leukemia at Blast Phase

The case of a 72-year-old woman with chronic myelogenous leukemia in blast phase (BP) with hypercalcemia is reported. Bone x-ray examination revealed multiple osteolytic lesions throughout the body. The serum level of parathyroid hormone-related protein (PTHrP) was elevated, and PTHrP messenger RNA (mRNA) was detectable in the peripheral blood mononuclear cells (PBMNC) at BP but was not detectable at chronic phase (CP).Treatment with conventional chemotherapy did not completely control either serum calcium level or serum PTHrP level. Treatment with imatinib mesylate (imatinib) alone rapidly normalized these parameters in parallel with a decrease in the number of blast cells. The treatment also maintained the patient in good condition for approximately 3 months, even though the number of blast cells, serum calcium level, serum PTHrP level, and PTHrP mRNA level increased at the terminal stage. Mutations of the p53, K-Ras, and BCR-ABL genes in PBMNC at BP were absent. A noteworthy feature in this patient was that PBMNC at BP but not at CP showed high Lyn mRNA expression. Taken together the findings showed that production of PTHrP by blast cells was favorably controlled by imatinib therapy alone. Imatinib may prolong survival time at BP even though the patients have the complication of PTHrP-mediated hypercalcemia.

Inv(16)(p13q22) in Chronic Myelogenous Leukemia in Blast Phase

Blast phase (BP) in chronic myelogenous leukemia (CML) frequently is accompanied by cytogenetic abnormalities in addition to t(9;22)(q34;q11.2). We describe 5 patients with CML in blast phase (CML-BP) in which t(9;22) and inv(16)(p13q22) were identified by conventional cytogenetics, with confirmation of BCR/ABL and CBF⇓/MYH11 by fluorescence in situ hybridization. The morphologic findings at the time of BP resembled de novo acute myeloid leukemia (AML) carrying inv(16)(p13q22), with abnormal eosinophils in the bone marrow and monocytosis in the peripheral blood in all cases. In 1 patient, inv(16)(p13q22) and abnormal eosinophils were detected in the bone marrow 2 months before CML-BP. The clinical course of these patients was similar to patients with CML-BP without evidence of inv(16)(p13q22). These cases illustrate that inv(16)(p13q22) is a form of cytogenetic evolution that rarely occurs in patients with CML at the time of BP. In this setting, unlike de novo AML, inv(16)(p13q22) in CML-BP is not associated with a favorable prognosis.

Inv(16)(p13q22) in Chronic Myelogenous Leukemia in Blast Phase

Blast phase (BP) in chronic myelogenous leukemia (CML) frequently is accompanied by cytogenetic abnormalities in addition to t(9;22)(q34;q11.2). We describe 5 patients with CML in blast phase (CML-BP) in which t(9;22) and inv(16)(p13q22) were identified by conventional cytogenetics, with confirmation of BCR-ABL and CBFss-MYH11 by fluorescence in situ hybridization. The morphologic findings at the time of BP resembled de novo acute myeloid leukemia (AML) carrying inv(16)(p13q22), with abnormal eosinophils in the bone marrow and monocytosis in the peripheral blood in all cases. In 1 patient, inv(16)(p13q22) and abnormal eosinophils were detected in the bone marrow 2 months before CML-BP. The clinical course of these patients was similar to patients with CML-BP without evidence of inv(16)(p13q22). These cases illustrate that inv(16)(p13q22) is a form of cytogenetic evolution that rarely occurs in patients with CML at the time of BP. In this setting, unlike de novo AML, inv(16)(p13q22) in CML-BP is not associated with a favorable prognosis.

Phase II study of troxacitabine, a novel dioxolane nucleoside analog, in patients with untreated or imatinib mesylate-resistant chronic myelogenous leukemia in blastic phase

A phase II study of troxacitabine, a non-natural dioxolane nucleoside l-enantiomer, was conducted in patients with chronic myelogenous leukemia in blastic phase (CML-BP). Patients were untreated for BP, or treated with imatinib mesylate (IM) as sole prior therapy for BP. Troxacitabine was given as an intravenous infusion over 30 min daily for 5 days at a dose of 8.0 mg/m 2 per day. Thirty-one patients, 29 (93%) of whom had failed prior IM therapy, received 51 courses of therapy. Grade 3 or 4 toxicities included stomatitis (4%), hand-foot syndrome (18%), and skin rash (12%). Four patients (13%) responded. Troxacitabine-based combinations merit study in IM-resistant CML.

Phase II Study of Troxacitabine, a Novel Dioxolane Nucleoside Analog, in Patients With Refractory Leukemia

PURPOSE: To investigate the activity of a novel dioxolane l-nucleoside analog, troxacitabine (l-(−)-OddC, BCH-4556), in patients with refractory leukemia. PATIENTS AND METHODS: Study participants were patients with refractory or relapsed acute myeloid (AML) or lymphocytic (ALL) leukemia, myelodysplastic syndromes (MDS), or chronic myelogenous leukemia in blastic phase (CML-BP). Troxacitabine was provided as an intravenous infusion for more than 30 minutes daily for 5 days at a dose of 8.0 mg/m2/d (40 mg/m2 per course). Courses were given every 3 to 4 weeks according to antileukemic efficacy. RESULTS: Forty-two patients (AML, 18 patients; MDS, one patient; ALL, six patients; CML-BP, 17 patients) were treated. Median age was 51 years (range, 23 to 80 years); 22 patients were male. Stomatitis was the most significant adverse event, with three patients (7%) and two patients (5%), respectively, experiencing grade 3 or 4 toxicity. Ten patients (24%) had grade 3 hand-foot syndrome, and two patients (5%) had grade 3 skin rash. One patient (2%) had grade 3 fatigue and anorexia. Marrow hypoplasia occurred between days 14 and 28 in 12 (75%) of 16 assessable patients with AML. Two complete remissions and one partial remission (18%) were observed in 16 assessable patients with AML. None of six patients with ALL responded. Six (37%) of 16 assessable patients with CML-BP experienced a return to chronic-phase disease. CONCLUSION: Troxacitabine has significant antileukemic activity in patients with AML and CML-BP.

Chronic myelogenous leukemia in nonlymphoid blastic phase: analysis of the results of first salvage therapy with three different treatment approaches for 162 patients.

The prognoses of patients with chronic myelogenous leukemia in blastic phase (CML-BP) are extremely poor. Treatment of patients with nonlymphoid CML-BP is associated with very low response rates, a median survival of 2-3 months, and significant toxicities. The aim of this study was to evaluate the results of therapy in CML-BP with different treatments in relation to response rate, survival, and toxicity. A total of 162 adults patients with a diagnosis of nonlymphoid CML-BP referred from 1986 to 1997 were included in this analysis. Only first salvage therapy was considered for the purpose of this analysis. The blastic phase of CML was defined by the presence of 30% or more blasts in the blood or bone marrow, or extramedullary disease. Ninety patients were treated with intensive chemotherapy, 31 with decitabine, and 41 with other single agents. Thirty-six patients (22%) had an objective response. Response rates were similar among patients treated with intensive chemotherapy (28%) or with decitabine (26%). In aggregate, other single agents showed objective response rates of 7%. The median duration of remission for all patients was 29 weeks and the median overall survival 22 weeks. Patients treated with decitabine showed a trend toward better survival, despite a higher percentage of older patients (P < 0.004). The median survival times were 29 weeks with decitabine, 21 weeks with intensive chemotherapy, and 22 weeks with other agents. When only older patients were considered, survival was significantly better with decitabine versus other treatments (P < 0.01). A multivariate analysis of prognostic factors for survival confirmed the independent, significant favorable effect of decitabine therapy (P = 0.047). In all groups complications of myelosuppression were the most significant side effects. Severe nonhematologic toxicities were not observed in patients treated with decitabine; they occurred in 20% and 17% of patients treated with intensive chemotherapy or other single agents, respectively. Compared with intensive chemotherapy, decitabine showed favorable results, with similar objective response rates, a better nonhematologic toxicity profile, and a trend for better survival, particularly among older patients. Studies will now attempt to combine decitabine with other promising approaches, such as homoharringtonine, low dose cytarabine, and interferon-alpha, in all CML phases.

Phase I and pharmacologic study of 9-aminocamptothecin colloidal dispersion formulation in patients with refractory or relapsed acute leukemia

Topoisomerase I inhibitors have shown promising anti leukemic activity in acute myelogenous leukemia (AML) and myelodysplastic syndrome. In this phase I study, we investigated the toxicity profile, pharmacokinetics, and activity of a prolonged continuous infusion schedule of the colloidal dispersion formulation of 9-amino-camptothecin (9-AC/CD) in patients with acute leukemia. Patients with refractory or relapsed AML, acute lymphocytic leukemia (ALL) or chronic myelogenous leukemia in blastic phase (CML-BP) were included in the study. Eligibility criteria were age greater than 15 years, performance status of 2 or better, creatinine < 1.5 mg/dl, and bilirubin < 1.5 mg/dl. 9-AC/CD was given as a continuous intravenous infusion over seven days every three to four weeks. The starting dose was 0.2 mg/m2/d (1.4 mg/m2/course). Courses were given every three to four weeks according to toxicity and anti leukemic efficacy. This phase I study used the classical 3 + 3 design. The dose was escalated by 50% until grade I toxicity was observed, and then by 30% to 35% until the dose limiting toxicity was defined. At the maximal tolerated dose (MTD), 8 to 10 patients were planned to be treated to better define the toxicity and early-activity profiles. Thirty-nine patients (AML thirty-six patients; ALL two patients; CML-BP one patient), median age 56 years, were treated. Severe mucositis was the dose limiting toxicity; it occurred in three of six patients treated at a dose of 1.6 mg/m2/d. The MTD was defined as 1.4 mg/m2/day by the phase I design. Upon expansion of the number of patients, 3 of 10 patients had grade 4 mucositis and 1 of 10 patients had grade 3 diarrhea. Nausea and vomiting were uncommon. No complete or partial remission was observed in 37 evaluable patients. However, 9-AC/CD exhibited antileukemic activity, as reflected by the finding of marrow hypoplasia on day 14 in 46% of the patients. Average steady-state concentration of 9-AC lactone was close to 10 nmol/l, and the of 9-AC lactone area under curve (AUC) was 1409 +/- 705 nmol/l. hr. The MTD of 9-AC/CD given as a seven-day continuous infusion was 1.4 mg/m2/d (9.8 mg/m2/course) in patients with acute leukemia. This represents three to fourfold dose escalation compared with the MTD of 9-AC given as shorter continuous infusion (three days) in patients with solid tumors. Future studies will determine the activity of prolonged administration of 9-AC/CD in patients with better prognosis acute leukemia.

Phase I Study of Arabinosyl-5-zacytidine (Fazarabine) in Adult Acute Leukemia and Chronic Myelogenous Leukemia in Blastic Phase

Fazarabine has demonstrated a broad spectrum of antitumor activity in experimental models including P388 and L1210 cell lines. Previous phase I clinical trials using a 3-ay continuous infusion schedule of Fazarabine have shown myelosuppression to be the dose limiting toxic-ity in solid tumors. Based on this clinical and preclinical experience we designed a phase I study to determine the toxicity, maximum tolerated dose (MTD), and antileukemic efficacy of Fazarabine using a 3-ay continuous infusion schedule in patients with refractory or relapsed acute leukemia or chronic myelogenous (CML) in blastic phase. Adults with a diagnosis of acute leukemia or blastic phase CML who were refractory or had relapsed on salvage chemotherapy were entered on study. Fazarabine was administered as a continuous infusion over 3 days every 3 to 4 weeks. The initial dose was 2 mg/m2/hour ± 72 hours. Results showed that the MTD was 425 mg/m2/hour infused over 72 hours every 3 to 4 weeks. At this dose level neurotoxicity and fluid overload were the dose limiting toxicities. Among 71 patients treated, we observed one complete remission, one partial remission and one hematologic improvement. No obvious dose response relationship could be determined. In conclusion, Fazarabine has not shown a beneficial effect in the therapy of acute leukemia. Since 71 patients and 20 dose levels were required to determine the MTD of Fazarabine, a reassessment of our phase I study designs should be considered to provide patients with better potential toxic: therapeutic benefits in such trials.

Chemotherapy-induced acral erythema in leukemic patients: a report of 15 cases.

Chemotherapy-induced acral erythema is a distinct localized cutaneous response to certain systemic chemotherapeutic agents. Between January 1990 and December 1994, from a total of 76 leukemic patients who have received combination chemotherapy consisting of cytosine arabinoside and anthracycline antibiotics, 15 patients developed chemotherapy-induced acral erythema. Fourteen of the patients had acute myelocytic leukemia, and one of them had chronic myelogenous leukemia in blast phase. Clinical features of these 15 patients have been analysed. Biopsy specimens obtained from eight of the patients were also evaluated for histopathologic alterations. The overall incidence of this reaction was found to be 19.7% in our group of patients receiving this chemotherapy protocol. The onset of reaction varied from the fourth to the seventeenth days of the chemotherapy and resolved within 2 weeks in most of the patients. Lesions appeared as well-defined erythema and edema involving the palmar surfaces in all of the patients. In nine of the patients the reaction recurred with subsequent chemotherapies. Scattered necrotic keratinocytes, vacuolar alterations of the basal layer, and mild to moderate perivascular lymphocytic infiltration in the dermis were the histopathologic findings observed in the biopsy specimens. Chemotherapy-induced acral erythema is a frequent reaction in patients who are receiving high-dose chemotherapy. For patients in whom this self-limited condition develops, reassurance is the mainstay of therapy. Awareness of this reaction is also important to be able to differentiate it from acute graft versus host disease in patients who receive bone marrow transplants.

Phase I clinical and laboratory evaluation of topotecan and cytarabine in patients with acute leukemia.

To determine the maximal-tolerated dose (MTD) of topotecan with cytarabine in acute leukemia patients, and to evaluate leukemia cell apoptosis in these patients. Fifty-three patients with acute leukemia not responsive to standard therapy were treated at eight dose levels of topotecan (2.5 mg/m2/d to 7.75 mg/m2/d). Topotecan was given as a 30-minute infusion daily with cytarabine 1 g/m2/d, both for 5 days. Using a flow-cytometric technique, the percent apoptotic cells in blood and bone marrow samples was determined, and the cell cycle distribution of the leukemic cells studied. Oropharyngeal mucositis was dose-limiting. The MTD of topotecan was 4.75 mg/m2/d for 5 days in high-risk patients and 7.0 mg/m2/d for 5 days in low-risk patients. The mean percent apoptotic cells in the peripheral blood reached a peak of 18.8%, a median of 48 hours following the first dose of topotecan. Patients with higher S-phase fractions, either before treatment or following cytarabine, were more likely to achieve bone marrow aplasia than those with lower S-phase fractions (P = .01 and P < .05, respectively). Clinical responses were seen in four of 39 patients with acute myelogenous leukemia (AML; of whom 32 had received prior high-dose cytarabine), three of six with acute lymphoblastic leukemia (ALL), and one of eight with chronic myelogenous leukemia in blast phase (CML-BP). The recommended phase II dose of topotecan with intermediate-dose cytarabine is 4.75 mg/m2/d for high-risk patients and 7.0 mg/m2/d for low-risk patients. The percentage of cells in S phase was important in determining response to treatment.

Phase I study of Topotecan, a new topoisomerase I inhibitor, in patients with refractory or relapsed acute leukemia

The purpose of this study was to define, in a phase I study in leukemia, the maximally tolerated dose (MTD), major toxicities, and possible antitumor activity of Topotecan, a new topoisomerase I (topo I) inhibitor. Topotecan was delivered by a 5-day continuous infusion every 3 to 4 weeks to patients with refractory or relapsed acute leukemia, at doses ranging from 3.5 mg/m2 to 18 mg/m2 per course. Twenty-seven patients were treated, including 17 patients with acute myelogenous or undifferentiated leukemia, 7 with acute lymphocytic leukemia, and 3 with chronic myelogenous leukemia in blastic phase. Severe mucositis was the dose-limiting toxicity occurring in two of five patients treated with Topotecan 11.8 mg/m2 per course; a third patient had prolonged myelosuppression. At the MTD of 10 mg/m2 per course, 1 of 12 patients had severe mucositis and 5 had mild-to-moderate mucositis. Nausea, vomiting, diarrhea, and prolonged myelosuppression were uncommon. Three patients (11%) achieved a complete response, two (7%) had a partial response, and one (4%) had a hematologic improvement. The overall complete plus partial response rate was 19%, and 24% in acute myelogenous or undifferentiated leukemia. A novel in vitro assay that quantifies Topotecan-stabilized topo I-DNA complexes in patient samples was used, which demonstrated heterogeneity in the ability of Topotecan to interact with topo I, the intracellular target of Topotecan. This phase I study defined the MTD of Topotecan to be 10 mg/m2 by continuous infusion over 5 days every 3 to 4 weeks in patients with refractory or relapsed acute leukemia. Severe mucositis was the dose-limiting toxicity. Future studies will define the precise activity of Topotecan in different leukemia subsets, its efficacy in combination with other antileukemic drugs, and correlations between Topotecan-induced topo I-DNA complex formation and individual patient response to Topotecan.

Phase I Study of Topotecan, A New Topoisomerase I Inhibitor, in Patients With Refractory or Relapsed Acute Leukemia

Abstract The purpose of this study was to define, in a phase I study in leukemia, the maximally tolerated dose (MTD), major toxicities, and possible antitumor activity of Topotecan, a new topoisomerase I (topo I) inhibitor. Topotecan was delivered by a 5-day continuous infusion every 3 to 4 weeks to patients with refractory or relapsed acute leukemia, at doses ranging from 3.5 mg/m2 to 18 mg/m2 per course. Twenty-seven patients were treated, including 17 patients with acute myelogenous or undifferentiated leukemia, 7 with acute lymphocytic leukemia, and 3 with chronic myelogenous leukemia in blastic phase. Severe mucositis was the dose-limiting toxicity occurring in two of five patients treated with Topotecan 11.8 mg/m2 per course; a third patient had prolonged myelosuppression. At the MTD of 10 mg/m2 per course, 1 of 12 patients had severe mucositis and 5 had mild-to- moderate mucositis. Nausea, vomiting, diarrhea, and prolonged myelosuppression were uncommon. Three patients (11%) achieved a complete response, two (7%) had a partial response, and one (4%) had a hematologic improvement. The overall complete plus partial response rate was 19%, and 24% in acute myelogenous or undifferentiated leukemia. A novel in vitro assay that quantifies Topotecan-stabilized topo I-DNA complexes in patient samples was used, which demonstrated heterogeneity in the ability of Topotecan to interact with topo I, the intracellular target of Topotecan. This phase I study defined the MTD of Topotecan to be 10 mg/m2 by continuous infusion over 5 days every 3 to 4 weeks in patients with refractory or relapsed acute leukemia. Severe mucositis was the dose-limiting toxicity. Future studies will define the precise activity of Topotecan in different leukemia subsets, its efficacy in combination with other antileukemic drugs, and correlations between Topotecan-induced topo I-DNA complex formation and individual patient response to Topotecan.

Inhibition of Hydroxymethylglutaryl Coenzyme A Reductase Activity Induces a Paradoxical Increase in DNA Synthesis in Myeloid Leukemia Cells

The effects of competitive inhibition of hydroxymethylglutaryl coenzyme A (HMG CoA) reductase by compactin on the in vitro proliferation of peripheral blood myeloid leukemia cells were studied using the cells from 45 patients with acute myeloid leukemia or chronic myelogenous leukemia in blast phase. The cells from 58% of these patients showed a dose-related inhibition of DNA synthesis when incubated with compactin. Unexpectedly, cells from 18% of the patients were resistant to the inhibitory effects of compactin on DNA synthesis and responded to the HMG CoA reductase inhibition with an actual increase in the incorporation of 14C-labeled thymidine into DNA. Another 18% of the patients studied displayed both inhibition and stimulation of DNA synthesis in a biphasic response depending on the particular concentration of compactin used. The maximum enhanced rates of cellular DNA synthesis were observed with lower compactin concentrations (5 x 10(-7) mol/L) than were required for maximum inhibition of DNA synthesis (10(-5) mol/L). Leukemia cells displaying a stimulated response to compactin had a significantly lower baseline DNA synthetic rate than did cells that showed an inhibitory response of DNA synthesis to compactin. There was no correlation between these cells' varying DNA synthetic response to compactin and measures of baseline HMG CoA reductase activity or acetate conversion to cholesterol. Whereas the observation of cellular DNA synthesis stimulation by HMG CoA reductase inhibition has not been observed in other mammalian cells and seems paradoxical, explanations may emerge in light of our growing knowledge concerning the importance of isoprenylation for the function of certain cell regulatory proteins.

Inhibition of hydroxymethylglutaryl coenzyme A reductase activity induces a paradoxical increase in DNA synthesis in myeloid leukemia cells

The effects of competitive inhibition of hydroxymethylglutaryl coenzyme A (HMG CoA) reductase by compactin on the in vitro proliferation of peripheral blood myeloid leukemia cells were studied using the cells from 45 patients with acute myeloid leukemia or chronic myelogenous leukemia in blast phase. The cells from 58% of these patients showed a dose-related inhibition of DNA synthesis when incubated with compactin. Unexpectedly, cells from 18% of the patients were resistant to the inhibitory effects of compactin on DNA synthesis and responded to the HMG CoA reductase inhibition with an actual increase in the incorporation of 14C-labeled thymidine into DNA. Another 18% of the patients studied displayed both inhibition and stimulation of DNA synthesis in a biphasic response depending on the particular concentration of compactin used. The maximum enhanced rates of cellular DNA synthesis were observed with lower compactin concentrations (5 x 10(-7) mol/L) than were required for maximum inhibition of DNA synthesis (10(-5) mol/L). Leukemia cells displaying a stimulated response to compactin had a significantly lower baseline DNA synthetic rate than did cells that showed an inhibitory response of DNA synthesis to compactin. There was no correlation between these cells' varying DNA synthetic response to compactin and measures of baseline HMG CoA reductase activity or acetate conversion to cholesterol. Whereas the observation of cellular DNA synthesis stimulation by HMG CoA reductase inhibition has not been observed in other mammalian cells and seems paradoxical, explanations may emerge in light of our growing knowledge concerning the importance of isoprenylation for the function of certain cell regulatory proteins.

Differential Expression of CD54/Intercellular Adhesion Molecule-1 in Myeloid Leukemias and in Lymphoproliferative Disorders

Indirect immunofluorescence staining with monoclonal antibody (MoAb) CL203.4 of malignant cells from 269 patients with hematologic malignancies showed a heterogeneous expression of CD54/intercellular adhesion molecule-1 (ICAM-1). This marker was expressed by malignant cells of 57 out of 118 patients with myeloid malignancies and 69 out of 135 with B-lymphoid malignancies. On the other hand, CD54 was not detected on malignant cells of 16 patients with T-lymphoid malignancies. In myeloid malignancies, CD54 is preferentially expressed by "stem cell-derived" malignancies, being detectable on blast cells from almost all patients affected by chronic myelogenous leukemia in blast phase or myelodysplastic syndromes and by only 34% of patients with de novo acute myeloid leukemia (AML). The expression of CD54 did not correlate with any specific myeloid FAB subtype, although three cases of highly undifferentiated AML (FAB MO) displayed maximal levels of the antigen. The expression of CD54 in AML was significantly associated with that of CD34 and HLA-DR antigens. In B-lymphoid malignancies, CD54 expression appears to correlate with the differentiation stage of malignant cells, since B-origin acute lymphoblastic leukemias and conventional B-chronic lymphocytic leukemias (B-CLL; ie, "dim SIg" CLL) expressed lower levels of CD54 than more mature lymphoproliferative disorders ("bright SIg" CLL, prolymphocytic leukemias, and lymphoplasmacytic tumors). "High-grade" B-cell non-Hodgkin's lymphomas (B-NHL) express in general a higher level of CD54 than "low-grade" ones. This finding in conjunction with the expression of CD54 in all 17 patients with "bright SIg" CLL investigated (characterized by marked organomegaly and poor prognosis) suggest that the differential expression of CD54 in lymphoproliferative disorders may also relate to their degree of malignancy.

Differential expression of CD54/intercellular adhesion molecule-1 in myeloid leukemias and in lymphoproliferative disorders

Indirect immunofluorescence staining with monoclonal antibody (MoAb) CL203.4 of malignant cells from 269 patients with hematologic malignancies showed a heterogeneous expression of CD54/intercellular adhesion molecule-1 (ICAM-1). This marker was expressed by malignant cells of 57 out of 118 patients with myeloid malignancies and 69 out of 135 with B-lymphoid malignancies. On the other hand, CD54 was not detected on malignant cells of 16 patients with T-lymphoid malignancies. In myeloid malignancies, CD54 is preferentially expressed by “stem cell-derived” malignancies, being detectable on blast cells from almost all patients affected by chronic myelogenous leukemia in blast phase or myelodysplastic syndromes and by only 34% of patients with de novo acute myeloid leukemia (AML). The expression of CD54 did not correlate with any specific myeloid FAB subtype, although three cases of highly undifferentiated AML (FAB MO) displayed maximal levels of the antigen. The expression of CD54 in AML was significantly associated with that of CD34 and HLA-DR antigens. In B-lymphoid malignancies, CD54 expression appears to correlate with the differentiation stage of malignant cells, since B-origin acute lymphoblastic leukemias and conventional B-chronic lymphocytic leukemias (B-CLL; ie, “dim SIg” CLL) expressed lower levels of CD54 than more mature lymphoproliferative disorders (“bright SIg” CLL, prolymphocytic leukemias, and lymphoplasmacytic tumors). “High-grade” B- cell non-Hodgkin‧s lymphomas (B-NHL) express in general a higher level of CD54 than “low-grade” ones. This finding in conjunction with the expression of CD54 in all 17 patients with “bright SIg” CLL investigated (characterized by marked organomegaly and poor prognosis) suggest that the differential expression of CD54 in lymphoproliferative disorders may also relate to their degree of malignancy.