Primary mediastinal B-cell lymphoma: high frequency of BCL-6 mutations and consistent expression of the transcription factors OCT-2, BOB.1, and PU.1 in the absence of immunoglobulins

Although primary mediastinal (thymic) large B-cell lymphoma has been primarily studied, its precise phenotype, molecular characteristics, and histogenesis are still a matter of debate. The International Extranodal Lymphoma Study Group collected 137 such cases for extensive pathological review. Histologically, the lymphomatous growth was predominantly diffuse with fibrosis that induced compartmentalized cell aggregation. It consisted of large cells with varying degrees of nuclear polymorphism and clear to basophilic cytoplasm. On immunohistochemistry, the following phenotype was observed: CD45(+), CD20(+), CD79a(+), PAX5/BSAP(+), BOB.1(+), Oct-2(+), PU.1(+), Bcl-2(+), CD30(+), HLA-DR(+), MAL protein(+/-), Bcl-6(+/-), MUM1/IRF4(+/-), CD10(-/+), CD21(-), CD15(-), CD138(-), CD68(-), and CD3(-). Immunoglobulins were negative both at immunohistochemistry and in situ hybridization. Molecular analysis, performed in 45 cases, showed novel findings. More than half of the cases displayed BCL-6 gene mutations, which usually occurred along with functioning somatic IgV(H) gene mutations and Bcl-6 and/or MUM1/IRF4 expression. The present study supports the concept that a sizable fraction of cases of this lymphoma are from activated germinal center or postgerminal center cells. However, it differs from other aggressive B-cell lymphomas in that it shows defective immunoglobulin production despite the expression of OCT-2, BOB.1, and PU.1 transcription factors and the lack of IgV(H) gene crippling mutations.

Thalidomide in myelofibrosis with myeloid metaplasia: a pooled-analysis of individual patient data from five studies

Trials to determine the effect of thalidomide in patients with Myelofibrosis with Myeloid Metaplasia (MMM) have produced inconclusive results due to different criteria for response and heterogeneous study participants. We undertook a pooled-analysis to assess the effects of such treatment on a larger series of cases and with a uniform assessment of response. We used updated data on 62 individual patients from 5 phase II trials that evaluated thalidomide therapy in MMM patients. Responsewas judged on individual disease parameters, on the improvement of the Dupriez risk categories and on the improvement of a 6 point "severity score" based on myeloproliferative and myelodepletive indexes of the disease. Overall, using standard dose of thalidomide, i.e. starting with no less than 100 mg/day, 49 patients (79%) had more than 4 weeks of therapy. Twenty-nine percent of patients with moderate to severe anemia showed an increase in hemoglobin or reduction/abolishment of blood transfusion requirements, 38% with moderate to severe thrombocytopenia had an increase in platelet counts, and 41% with high grade splenomegaly demonstrated a measurable reduction in splenic size. These effects led to an absolute decrease in the "severity" score in 44.9% of the patients. Major disease severity and high degrees of splenomegaly before therapy predicted response with a probability of 61.9%. However, worsening of the "severity" score was observed in 20.4% of the patients, 18% having a "myeloproliferative reaction" with leukocytosis and/or thrombocytosis. Sixty-six percent of the patients discontinued the drug before 6 months of treatment due to intolerance. In conclusion, there is a small but clear improvement of disease severity with thalidomide therapy in MMM. The potential for myeloproliferative reactions and the unfavorable dose-related toxicity profile argue for future studies using lower doses of this drug.

Clinical efficacy and antiangiogenic activity of thalidomide in myelofibrosis with myeloid metaplasia. A pilot study

Increased neoangiogenesis has been reported in myelofibrosis with myeloid metaplasia (MMM). Thus we studied the effects of thalidomide, an antiangiogenic drug, in 12 MMM patients. Before treatment, all the cases showed a significantly increased micro-vessel density (MVD); in all eight tested cases bFGF and VEGF plasma levels were higher than controls. All patients presented disease progression in the last 3 months with standard therapy, regarding splenomegaly, anemia and/or thrombocytopenia and/or hyperleukocytosis. Thalidomide was administered at daily doses increasing from 100 to 600 mg. Eleven out of 12 patients were evaluable. No progression of disease was seen during the treatment in any case. In particular, spleen size decreased in 7/11 patients, anemia improved in 3/4 (two are now transfusion independent), thrombocytopenia in 2/2 and hyperleukocytosis in 2/5 patients. Side-effects were frequent, although not severe. After treatment, VEGF and bFGF plasma levels varied widely and in selected cases decreased. In particular, VEGF and/or bFGF decreased in 4/5 responders and in 1/3 non-responders. Moreover, MVD significantly decreased in all the responders evaluated after treatment. We conclude that thalidomide is a feasible therapy in MMM patients and looks promising at least to control the growth progression of disease.

Liposomal daunorubicin (DaunoXome) for treatment of poor-risk acute leukemia

Toxicity limits the use of anthracyclines in elderly sick patients and in heavily pretreated patients. Since the liposomal preparation of daunorubicin (DNR) (DaunoXome, or DNX) is expected to be less toxic than conventional DNR, we tested DNX combined with high-dose arabinosyl cytosine (HDAC) in 42 adult poor-risk acute leukemia patients. Thirty-one patients had acute non-lymphocytic leukemia (ANLL). Of these, 12 patients were newly diagnosed but were not eligible for standard induction treatment, 13 were in first relapse, and 6 were in second or subsequent relapse. Eleven patients had acute lymphocytic leukemia (ALL), in first (eight cases) or second (three cases) relapse. DNX was given i.v. in three doses of 80 or 100 mg/m(2) each (days 1-3) by a 60-min infusion in glucose 5%, followed by a 4-h infusion of HDAC 2 g/m(2) (days 1-5). Among 31 ANLL patients there were 16 (51%) complete remissions (CR), 5 deaths during induction, and 10 failures. Among 11 ALL patients there were 10 CRs and 1 failure. The response rate was not affected by the overexpression of MDR-related proteins (PgP, MRP-1, and LRP). Non-hemopoietic toxicity was negligible, with no intestinal toxicity and only one case of gram-negative bacteremia. We conclude that DNX, in combination with HDAC, is an effective treatment for poor-risk adult AL. Because of the low non-hematologic toxicity, it can be used to reinduce remission in poor-risk patients who are candidates for allogeneic bone marrow transplantation. The high CR rate observed in ALL requires confirmation.

Pneumocystis carinii pneumonia in patients with malignant haematological diseases: 10 years' experience of infection in GIMEMA centres

A retrospective survey was conducted over a 10-year period (1990-99) among 52 haematology divisions in order to evaluate the clinical and laboratory characteristics and outcome of patients with proven Pneumocystis carinii pneumonia (PCP) complicating haematological diseases. The study included 55 patients (18 with non-Hodgkin's lymphoma, 10 with acute lymphoblastic leukaemia, eight with acute myeloid leukaemia, five with chronic myeloid leukaemia, four with chronic lymphocytic leukaemia, four with multiple myeloma, three with myelodysplastic syndrome, two with myelofibrosis and one with thalassemia) who developed PCP. Among these, 18 (33%) underwent stem cell transplantation; only two received an oral prophylaxis with trimethroprim/sulphamethoxazole. Twelve patients (22%) developed PCP despite protective isolation in a laminar airflow room. The most frequent symptoms were: fever (86%), dyspnoea (78%), non-productive cough (71%), thoracic pain (14%) and chills (5%); a severe hypoxaemia was present in 39 patients (71%). Chest radiography or computerized tomography showed interstitial infiltrates in 34 patients (62%), alveolar infiltrates in 12 patients (22%), and alveolar-interstitial infiltrates in nine patients (16%). Bronchoalveolar lavage was diagnostic in 47/48 patients, induced sputum in 9/18 patients and lung biopsy in 3/8 patients. The diagnosis was made in two patients at autopsy. All patients except one started a specific treatment (52 patients trimethroprim/sulphamethoxazole, one pentamidine and one dapsone). Sixteen patients (29%) died of PCP within 30 d of diagnosis. Multivariate analysis showed that prolonged steroid treatment (P < 0.006) and a radiological picture of diffuse lung involvement (P < 0.003) were negative diagnostic factors.

Hodgkin's lymphoma: the pathologist's viewpoint

Despite its well known histological and clinical features, Hodgkin's lymphoma (HL) has recently been the object of intense research activity, leading to a better understanding of its phenotype, molecular characteristics, histogenesis, and possible mechanisms of lymphomagenesis. There is complete consensus on the B cell derivation of the tumour in most cases, and on the relevance of Epstein-Barr virus infection and defective cytokinesis in at least a proportion of patients. The REAL/WHO classification recognises a basic distinction between lymphocyte predominance HL (LP-HL) and classic HL (CHL), reflecting the differences in clinical presentation and behaviour, morphology, phenotype, and molecular features. CHL has been classified into four subtypes: lymphocyte rich, nodular sclerosing, with mixed cellularity, and lymphocyte depleted. The borders between CHL and anaplastic large cell lymphoma have become sharper, whereas those between LP-HL and T cell rich B cell lymphoma remain ill defined. Treatments adjusted to the pathobiological characteristics of the tumour in at risk patients have been proposed and are on the way to being applied.

Real-time quantitation of minimal residual disease in inv(16)-positive acute myeloid leukemia may indicate risk for clinical relapse and may identify patients in a curable state

The inv(16) cytogenetic subtype of acute myeloid leukemia (AML) has a relatively good prognosis. Many patients achieve complete remission (CR). The prognostic uncertainty of negative qualitative reverse transcription-polymerase chain reaction (RT-PCR) assays suggests the need to identify prognostically significant critical thresholds by real-time RT-PCR. A reliable and sensitive (10(-5)) real-time RT-PCR assay was set up for the evaluation of relevant CBFbeta-MYH11/ABL transcript ratios and was applied to the 21 patients with inv(16) AML routinely referred for cytogenetic and molecular monitoring in Seràgnoli Institute (Bologna, Italy) since 1990. Among the 18 patients who underwent ablative chemotherapy, all achieved CR with a 3-year disease-free survival probability of 63% (95% CI, 40%-87%) and no recorded events after 26 months. Five patients had relapses; 2 died of disease and 3 entered second CR. Analysis of the 125 bone marrow (or peripheral blood) samples studied by real-time RT-PCR showed that transcript ratios of samples taken during CR at any time before a relapse were always greater than 0.12%, whereas those of samples taken during first or second CR from patients who did not subsequently have relapses were always less than 0.25%. This suggests that transcript ratios greater than 0.25% may correspond to high risk for relapse, whereas ratios below 0.12% might indicate the patient is in a curable state. If confirmed, such thresholds could open the way to a new phase in post-CR therapeutic decision making for patients with inv(16) AML.

Pulsed ATRA as single therapy restores long-term remission in PML-RARalpha-positive acute promyelocytic leukemia patients: real time quantification of minimal residual disease. A pilot study

All-trans retinoic acid (ATRA), alone or combined with chemotherapy (CHT) is widely used to induce complete remission (CR) in newly diagnosed acute promyelocytic leukemia (APL). If used alone, ATRA results in a substantial proportion of CRs. To maintain remission further, ATRA is commonly used with cycles of CHT, frequently followed by autologous (auto) or allogeneic (allo) stem cell transplantation (SCT), as early reports have shown that the continuous administration of ATRA as single therapy almost invariably leads to relapse in a short period of time (months). Pharmacokinetic studies have shown that induced resistance to ATRA is frequently suppressed by the intermittent use of the drug. In this study we applied an intermittent therapeutic protocol with ATRA in five APL patients who were either molecularly refractory after combined ATRA/CHT treatment, or relapsed, or at diagnosis, but not eligible for the combination treatment because of previous toxicity. They were treated with ATRA (45 mg/m2/day) for 21 days. The treatment was then prolonged continuously for 1 week every 2 weeks. Molecular analysis was performed by qualitative and quantitative reverse transcription-polymerase chain reaction (RT-PCR). All patients obtained molecular remission, as assessed by qualitative RT-PCR, in a median of 3 months (range 1-15). Quantitative RT-PCR confirmed these data, showing a progressive reduction (1 or 2 logs) to a 'negligible quantity' of PML-RARalpha fusion transcript (ratio PML-RARalpha/ABL x 10(4) ABL < 10(-1)) in all but one patient treated with pulsed ATRA therapy. These data were confirmed with qualitative and quantitative RT-PCR. After a median follow-up of 17 months from the start of ATRA therapy, 4/5 patients (80%) are in continuous complete molecular remission. To our knowledge, this is the first clinical observation that intermittent ATRA therapy (without chemotherapy) is effective not only in inducing but also in maintaining long-term molecular remission in APL patients. This approach could therefore be effective, if confirmed in larger series, in relapsed/refractory patients unsuitable for high-dose therapy and SCT; it may be proposed as induction therapy for selected older APL patients if considered not to be eligible for combined ATRA/CHT due to inadequate performance status or concurrent disease.

Diffuse large B-cell lymphoma with primary retroperitoneal presentation: clinico-pathologic study of nine cases

Diffuse large B-cell lymphoma primarily presenting in the retroperitoneum (PRLBCL) has been the object of occasional reports, all based on dated techniques.

MATERIALS AND METHODS

Nine PRLBCLs--with clinical information and paraffin blocks available--were reviewed on morphologic, immunohistochemical and molecular grounds.

RESULTS

At microscopic examination, the cases were characterized by a diffuse proliferation of large cells (CD20+, CD79a+, CD3-), displaying a wide rim of cytoplasm (clear in seven instances and acidophilic in two), associated with sclerosis and frequent compartmentalization. Phenotypic and molecular analyses showed that: a) three cases were bcl-2+, bcl-6+, HLA-DR+, and CD10+ (1/3), with associated follicular dendritic cell (FDC) component and bcl-2 gene rearrangements; b) four cases were bcl-2, bcl-6, HLA-DR, CD10, FDC, and bcl-2 gene rearrangement negative; c) two cases had border-line characteristics (bcl-2+, bcl-6+, FDC+, HLA-DR-, CD10-, and bcl-2 gene rearrangement-). The first subgroup was thought to be of follicular derivation, as was the third due to bcl-6 and FDC stains. Of the corresponding five patients, three are in complete remission and two died of disease within 12 months. No obvious, normal counterpart was detected in the remaining four tumors: the corresponding patients died of disease in 3-23 months. The problem of similarities between PRLBCL and primary mediastinal LBCL is discussed.

CONCLUSIONS

Although the present series is small, our findings suggest that PRLBCL may represent a more heterogeneous group of tumors than previously thought, which merits further phenotypic and molecular studies to broaden the understanding of its histogenesis and behavior.

Myeloperoxidase expression by histiocytes in Kikuchi's and Kikuchi-like lymphadenopathy

Forty-five examples of Kikuchi's lymphadenitis (KL), 5 Kikuchi-like lupus erythematosus lymphadenopathies, 25 nonnecrotizing lymphadenitidies (5 toxoplasmic, 5 sarcoid-like, 6 dermatopathic, 4 suppurative, 3 tubercular, 2 with sinus histiocytosis), 4 examples of hyaline-vascular Castleman disease (CD), 2 plasmacytoid monocyte tumors (PM-Ts), and 61 accessory cell neoplasms were studied by a panel of antibodies, including the PG-M1 (against a macrophage-restricted CD68 epitope) and a polyclonal anti-myeloperoxidase (MPO). In KL and Kikuchi-like lupus erythematosus lymphadenopathies, 25 to 75% of CD68(+) histiocytes co-expressed MPO. This did not occur in nonnecrotizing lymphadenitidies and accessory cell neoplasms. MPO(+)/CD68(+) elements corresponded to nonphagocytosing mononuclear cells and some crescentic macrophages and phagocytosing histiocytes. Typical PMs were MPO(-)/CD68(+) in all cases, including CD and PM-T. Our observations suggest that in KL and KL-like lymphadenopathies: 1) MPO(+)/CD68(+) blood monocytes might be attracted into tissues because of the lack or paucity of granulocytes and the need of MPO for oxidative processes; 2) PMs are more likely to be involved in the cytotoxic immune reaction than in phagocytic phenomena; 3) the peculiar phenotype of the histiocytic component can be usefully used for the differentiation from malignant lymphoma and PM-T.

Combined action of PSC 833 (Valspodar), a novel MDR reversing agent, with mitoxantrone, etoposide and cytarabine in poor-prognosis acute myeloid leukemia

PSC 833 (Valspodar) can reverse multidrug resistance (MDR) in patients with hematologic malignancies, but alters the pharmacokinetics of concomitant anticancer agents. A phase I, dose-finding study was initiated to define a safe and effective regimen of mitoxantrone, etoposide, and cytarabine (MEC) when administered with PSC 833 to patients with early relapsed or refractory acute myeloid leukemia (AML). Poor-prognosis AML patients refractory to first-line induction therapy or relapsing within 9 months of attaining complete remission (CR) were treated with cytarabine (1.0 g/m2/day), etoposide (30 mg/m2/day), and mitoxantrone at a dose of either 3.0 mg/m2/day (cohort 1) or 4.5 mg/m2/day (cohorts 2 and 3) for 6 days plus continuous-infusion PSC 833 (10 mg/kg/24 h with a 2.0 mg/kg loading dose) for 6 or 7 days each 21-day cycle. Patients achieving CR were given a 4-day MEC plus PSC 833 consolidation cycle. Twenty-three patients were enrolled (eight with primary refractory AML and 15 in relapse). Dose-limiting toxicity occurred in one of six patients in cohort 2 (grade 4 mucositis) and one of seven patients in cohort 3 (grade 4 hyperbilirubinemia). The maximum tolerated dose of mitoxantrone was defined as 4.5 mg/m2/day. Clinically significant grade 4 hyperbilirubinemia, possibly related to PSC 833, occurred in four patients. Hematologic toxicities were as expected in this patient population, but were not dose limiting. Mild to moderate cerebellar ataxia and paresthesia occurred in six (26%) and five (22%) patients, respectively, but were not dose limiting. Overall, six of 23 (26%) patients achieved CR, including five patients with demonstrated P-glycoprotein expression and/or function. The median overall survival was 4 months. All six patients with a CR were alive and four (17%) patients were disease free at 12 months. Blood levels of PSC 833 were well above the target level of 1000 ng/ml, a concentration that is known to reverse MDR in vitro. PSC 833 reduced the clearance of etoposide by approximately two-fold. No correlation was observed between the mitoxantrone or etoposide area under the curve and response. In conclusion, the MEC plus PSC 833 tested regimen was well tolerated and the 26% CR rate warrants further testing of this regimen in a randomized, phase III trial.

The prognostic value of cytogenetics is reinforced by the kind of induction/consolidation therapy in influencing the outcome of acute myeloid leukemia--analysis of 848 patients

We studied the impact of cytogenetics and kind of induction/consolidation therapy on 848 adult acute myeloid leukemia (AML) patients (age 15-83). The patients received three types of induction/consolidation regimen: standard (daunorubicin and cytosine arabinoside (3/7); two cycles); intensive (idarubicin, cytosine arabinoside and etoposide (ICE), plus mitoxantrone and intermediate-dose Ara-C (NOVIA)); and low-dose (low-dose cytosine arabinoside). CR patients under 60 years of age, if an HLA-identical donor was available received allogeneic stem cell transplantation (allo-SCT); otherwise, as part of the program, they underwent autologous (auto)-SCT. CR rates significantly associated with 'favorable' (inv(16), t(8;21)), 'intermediate' ('no abnormality', abn(11q23), +8, del(7q)) and 'unfavorable' (del (5q), -7, abn(3)(q21q26), t(6;9), 'complex' (more than three unrelated cytogenetic abnormalities)) karyotypes (88% vs 65% vs 36%, respectively; P = 0.0001). These trends were confirmed in all age groups. On therapeutic grounds, intensive induction did not determine significant increases of CR rates in any of the considered groups, with respect to standard induction. Low-dose induction was associated with significantly lower CR rates. Considering disease-free survival (DFS), multivariate analysis of the factors examined (including karyotype grouping) showed that only age > 60 years significantly affected outcome. However, in cases where intensive induction was adopted, 'favorable' karyotype was significantly related to longer DFS (P = 0.04). This was mainly due to the favorable outcome of t(8;21) patients treated with intensive induction. Patients receiving allo-SCT had significantly longer DFS (P = 0.005); in particular, allo-SCT significantly improved DFS in the 'favorable' and 'intermediate' groups (P = 0.04 and P = 0.048, respectively). In conclusion our study could provide some guidelines for AML therapy: (1) patients in the 'favorable' karyotype group seem to have a longer DFS when treated with an intensive induction/consolidation regimen, adopted before auto-SCT instead of standard induction; this underlines the importance of reinforcement of chemotherapy, not necessarily based on repeated high-dose AraC cycles. Allo-SCT, independently of induction/consolidation therapy, should be considered an alternative treatment; (2) patients in the 'intermediate' karyotype group should receive allo-SCT; (3) patients in the 'unfavorable' karyotype group should be treated using investigational chemotherapy, considering that even allo-SCT cannot provide a significantly longer DFS, but only a trend to a better prognosis.

Double reinforcement with fludarabine/high-dose cytarabine enhances the impact of autologous stem cell transplantation in acute myeloid leukemia patients

Reinforced chemotherapy based on a double high-dose consolidation regimen could be a different way to enhance in vivo purging prior to autologous stem cell transplantation (auto-SCT) in acute myeloid leukemia (AML). We investigated the impact on outcome of auto-SCT after two different strategies of early intensification performed after an identical induction regimen in adult patients with AML. Between January 1993 and December 1998, 140 consecutive AML patients were enrolled in a program consisting of an identical anthracycline-based induction (ICE) and two different consolidation regimens: one cycle, cytarabine-based (single-NOVIA: 91 patients); two cycles, fludarabine-based (double-FLAN: 49 patients). Seventy out of 91 patients received single-NOVIA consolidation: 60 underwent a transplantation procedure (allogeneic bone marrow transplantation (allo-BMT):16 patients; auto-SCT: 44). Thirty-five out of 49 patients received double-FLAN consolidation: 31 underwent a transplantation procedure (allo-BMT: 10; auto-SCT: 21). The double consolidation regimen was well-tolerated with only minor side-effects. Median follow-up observation time for surviving patients was 38 months (range, 17-71) for the double-FLAN consolidation group and 70 months (range: 48-93) for the single-NOVIA consolidation group. Among the patients who received auto-SCT, the double consolidation strategy produced a superior disease-free survival curve at 36 months (78.6% (95%CI: 59.4-97.8) vs 47.7% (95%CI: 33-62.4)) compared with the single-NOVIA group. This difference was confirmed when the patients were analyzed for intention to treat (P = 0.04). In addition, the double-FLAN consolidation group showed a superior overall survival and lower relapse rate (P = 0.02). We conclude that the double-FLAN reinforcement strategy is safe and enhances the clinical impact of auto-SCT for AML patients in first complete remission. It may provide specific clinical benefit for patients undergoing auto-SCT.

The pathologist's view point. Part I--indolent lymphomas

BACKGROUND AND OBJECTIVES

The REAL/WHO classification constitutes a new tool for the better understanding and treatment of malignant lymphomas. The authors focus on the key features of B-cell lymphomas with an indolent behavior, aiming to contribute to the cross-talk between pathologists and clinicians.

DATA SOURCES AND METHODS

Each lymphoma entity is analyzed on the basis of the most representative contributions in the literature and the authors' experience gained in studying more than 20,000 lymphoid tumors over a 20-year period.

RESULTS

Guidelines for diagnosis and areas of interest for future clinico-pathologic studies are identified and discussed. Within this context, selected data obtained by the application of novel markers are presented.

INTERPRETATION AND CONCLUSIONS

The present know- ledge and organization of malignant lymphomas now make the development of tailored therapies a feasible goal.

The pathologist's view point. Part II --aggressive lymphomas

BACKGROUND AND OBJECTIVES

The REAL/WHO classification constitutes a new tool for the better understanding and treatment of malignant lymphomas. The authors focus on the key features of aggressive B- and T-cell lymphomas, aiming to contribute to the cross-talk between pathologists and clinicians.

DATA SOURCES AND METHODS

Each lymphoma entity is analyzed on the basis of the most representative contributions in the literature and the authors' experience gained in studying more than 20,000 lymphoid tumors over a 20-year period.

RESULTS

Guidelines for diagnosis and areas of interest for future clinico-pathologic studies are identified and discussed. Within this context, selected data obtained by the application of novel markers are presented.

INTERPRETATION AND CONCLUSIONS

The present know- ledge and organization of malignant lymphomas now make the development of tailored therapies a feasible goal.