Emanuela Boveri

JAK2 or CALR mutation status defines subtypes of essential thrombocythemia with substantially different clinical course and outcomes

Patients with essential thrombocythemia may carry JAK2 (V617F), an MPL substitution, or a calreticulin gene (CALR) mutation. We studied biologic and clinical features of essential thrombocythemia according to JAK2 or CALR mutation status and in relation to those of polycythemia vera. The mutant allele burden was lower in JAK2-mutated than in CALR-mutated essential thrombocythemia. Patients with JAK2 (V617F) were older, had a higher hemoglobin level and white blood cell count, and lower platelet count and serum erythropoietin than those with CALR mutation. Hematologic parameters of patients with JAK2-mutated essential thrombocythemia or polycythemia vera were related to the mutant allele burden. While no polycythemic transformation was observed in CALR-mutated patients, the cumulative risk was 29% at 15 years in those with JAK2-mutated essential thrombocythemia. There was no significant difference in myelofibrotic transformation between the 2 subtypes of essential thrombocythemia. Patients with JAK2-mutated essential thrombocythemia and those with polycythemia vera had a similar risk of thrombosis, which was twice that of patients with the CALR mutation. These observations are consistent with the notion that JAK2-mutated essential thrombocythemia and polycythemia vera represent different phenotypes of a single myeloproliferative neoplasm, whereas CALR-mutated essential thrombocythemia is a distinct disease entity.

Survival and Disease Progression in Essential Thrombocythemia Are Significantly Influenced by Accurate Morphologic Diagnosis: An International Study

PURPOSE The WHO diagnostic criteria underscore the role of bone marrow (BM) morphology in distinguishing essential thrombocythemia (ET) from early/prefibrotic primary myelofibrosis (PMF). This study examined the clinical relevance of such a distinction. METHODS Representatives from seven international centers of excellence for myeloproliferative neoplasms convened to create a clinicopathologic database of patients previously diagnosed as having ET (N = 1,104). Study eligibility criteria included availability of treatment-naive BM specimens obtained within 1 year of diagnosis. All bone marrows subsequently underwent a central re-review. RESULTS Diagnosis was confirmed as ET in 891 patients (81%) and was revised to early/prefibrotic PMF in 180 (16%); 33 patients were not evaluable. In early/prefibrotic PMF compared with ET, the 10-year survival rates (76% and 89%, respectively) and 15-year survival rates (59% and 80%, respectively), leukemic transformation rates at 10 years (5.8% and 0.7%, respectively) and 15 years (11.7% and 2.1%, respectively), and rates of progression to overt myelofibrosis at 10 years (12.3% and 0.8%, respectively) and 15 years (16.9% and 9.3%) were significantly worse. The respective death, leukemia, and overt myelofibrosis incidence rates per 100 patient-years for early/prefibrotic PMF compared with ET were 2.7% and 1.3% (relative risk [RR], 2.1; P < .001), 0.6% and 0.1% (RR, 5.2; P = .001), and 1% and 0.5% (RR, 2.0; P = .04). Multivariable analysis confirmed these findings and also identified age older than 60 years (hazard ratio [HR], 6.7), leukocyte count greater than 11 × 10(9)/L (HR, 2.01), anemia (HR, 2.95), and thrombosis history (HR, 2.81) as additional risk factors for survival. Thrombosis and JAK2V617F incidence rates were similar between the two groups. Survival in ET was similar to the sex- and age-standardized European population. CONCLUSION This study validates the clinical relevance of strict adherence to WHO criteria in the diagnosis of ET and provides important information on survival, disease complication rates, and prognostic factors in strictly WHO-defined ET and early/prefibrotic PMF.

A prospective study of 338 patients with polycythemia vera: the impact of JAK2 (V617F) allele burden and leukocytosis on fibrotic or leukemic disease transformation and vascular complications

We studied the relationship between JAK2 (V617F) mutant allele burden and clinical phenotype, disease progression and survival in patients with polycythemia vera (PV). The percentage of granulocyte mutant alleles was evaluated using a quantitative real-time polymerase chain reaction-based allelic discrimination assay. Of the 338 patients enrolled in this prospective study, 320 (94.7%) carried the JAK2 (V617F) mutation. Direct relationships were found between mutant allele burden and hemoglobin concentration (P=0.001), white blood cell count (P=0.001), spleen size (P=0.001) and age-adjusted bone marrow cellularity (P=0.002), while an inverse relationship was found with platelet count (P<0.001). During the study period, eight patients progressed to post-PV myelofibrosis (MF) (all carrying >50% mutant alleles), while 10 patients developed acute myeloid leukemia (AML). The mutant allele burden was significantly related to the risk of developing myelofibrosis (P=0.029) and retained its significant effect also in multivariable analysis (P=0.03). By contrast, the risk of developing AML as well as that of thrombosis was not significantly related to mutant allele burden. Leukocytosis did not affect thrombosis, MF, leukemia or survival. In conclusion, a JAK2 (V617F) allele burden >50% represents a risk factor for progression to MF in PV.

CD30/Ki-1-positive lymphoproliferative disorders of the skin - Clinicopathologic correlation and statistical analysis of 86 cases: A multicentric study from the European organization for research and treatment of cancer cutaneous lymphoma project group

PURPOSE Recently, it has been shown that CD30 antigen expression is associated with a relatively favorable prognosis in primary cutaneous large-cell lymphomas (CLCLs). However, prognostic subsets within the CD30+ group have been difficult to identify due to lack of uniform clinicopathologic and immunophenotypic criteria, limited clinical information, and the inclusion of relatively few patients for statistical analysis in prior studies. To address these problems, we formed a multicentric study group of pathologists and dermatologists to classify and evaluate 92 cases of CD30+ cutaneous lymphoproliferative disorders. PATIENTS AND METHODS An expert panel established consensus diagnoses for 86 CD30+ cutaneous lymphomas. Cases, clinically and histologically classified as lymphomatoid papulosis (LyP), anaplastic large-cell lymphoma (ALCL), nonanaplastic lymphoma, and borderline histology between LyP and ALCL, were then analyzed statistically by univariate, multivariate, and Cox regression model analysis of potential prognostic features. RESULTS Spontaneous regression and age less than 60 years were associated with a favorable prognosis, while extracutaneous disease and age greater than 60 had a poor prognosis. Patients with LyP had the best prognosis, followed by those with primary CD30+ lymphomas, regardless of cytologic type (anaplastic or nonanaplastic). Borderline cases, morphologically indistinguishable from LyP and CD30+ ALCL, had a favorable prognosis, similar to LyP. CONCLUSION Our findings indicate that CD30+ cutaneous lymphoproliferative disorders comprise a spectrum of closely related skin lesions, which can be assigned a relatively favorable or unfavorable prognosis by a combined clinical and pathologic analysis.

Prognostic factors for thrombosis, myelofibrosis, and leukemia in essential thrombocythemia: a study of 605 patients

The findings from this study on a large series of patients treated according to current clinical practice provide reassurance that essential thrombocythemia is an indolent disorder and affected patients have a long survival. Background Essential thrombocythemia is a chronic myeloproliferative disorder; patients with this disorder have a propensity to develop thrombosis, myelofibrosis, and leukemia. Design and Methods We studied 605 patients with essential thrombocythemia (follow-up 4596 person-years) with the aim of defining prognostic factors for thrombosis, myelofibrosis, and leukemia during follow-up. Results Sixty-six patients (11%) developed thrombosis with a 10-year risk of 14%. Age >60 years (p<0.001) and a history of thrombosis (p=0.03) were independent risk factors for thrombosis. Progression to myelofibrosis occurred in 17 patients (2.8%) with a 10-year risk of 3.9%. Anemia at diagnosis of essential thrombocythemia was significantly correlated (p<0.001) with progression to myelofibrosis. Leukemia occurred in 14 patients (2.3%) at a median time of 11 years after the diagnosis of essential thrombocythemia; the risk was 2.6% at 10 years. Age >60 years (p=0.02) was significantly correlated with the development of leukemia. Cytotoxic treatment did not imply a higher risk of leukemia. At the time of the analysis, 64 of the 605 patients (10.6%) had died. The 10-year probability of survival was 88%, with a median survival of 22.3 years. Age >60 years (p<0.001) and history of thrombosis (p=0.001) were independent risk factors for survival. Conclusions The findings from this study on a large series of patients treated according to current clinical practice provide reassurance that essential thrombocythemia is an indolent disorder and affected patients have a long survival. The main risk is thrombosis, while myelofibrosis and leukemia are rare and late complications.

Clinical effect of driver mutations of JAK2, CALR, or MPL in primary myelofibrosis

We studied the impact of driver mutations of JAK2, CALR, (calreticulin gene) or MPL on clinical course, leukemic transformation, and survival of patients with primary myelofibrosis (PMF). Of the 617 subjects studied, 399 (64.7%) carried JAK2 (V617F), 140 (22.7%) had a CALR exon 9 indel, 25 (4.0%) carried an MPL (W515) mutation, and 53 (8.6%) had nonmutated JAK2, CALR, and MPL (so-called triple-negative PMF). Patients with CALR mutation had a lower risk of developing anemia, thrombocytopenia, and marked leukocytosis compared with other subtypes. They also had a lower risk of thrombosis compared with patients carrying JAK2 (V617F). At the opposite, triple-negative patients had higher incidence of leukemic transformation compared with either CALR-mutant or JAK2-mutant patients. Median overall survival was 17.7 years in CALR-mutant, 9.2 years in JAK2-mutant, 9.1 years in MPL-mutant, and 3.2 years in triple-negative patients. In multivariate analysis corrected for age, CALR-mutant patients had better overall survival than either JAK2-mutant or triple-negative patients. The impact of genetic lesions on survival was independent of current prognostic scoring systems. These observations indicate that driver mutations define distinct disease entities within PMF. Accounting for them is not only relevant to clinical decision-making, but should also be considered in designing clinical trials.

Prevalence and clinical significance of the MYD88 (L265P) somatic mutation in Waldenstrom's macroglobulinemia and related lymphoid neoplasms.

A study has shown that MYD88 (L265P) is a recurring somatic mutation in Waldenströms macroglobulinemia (WM). We developed an allele-specific polymerase chain reaction (PCR) for this mutation, and analyzed bone marrow or peripheral blood samples from 58 patients with WM, 77 with IgM monoclonal gammopathy of undetermined significance (IgM-MGUS), 84 with splenic marginal zone lymphoma (SMZL), and 52 with B-cell chronic lymphoproliferative disorders (B-CLPD). MYD88 (L265P) was detected in 58/58 (100%) patients with WM, 36/77 (47%) with IgM-MGUS, 5/84 (6%) with SMZL, and 3/52 (4%) with B-CLPD. Compared to IgM-MGUS patients with wild-type MYD88, those carrying MYD88 (L265P) showed significantly higher levels of IgM (P < .0001) and presented Bence-Jones proteinuria more frequently at diagnosis (P = .002). During follow-up, 9 patients with IgM-MGUS progressed to WM or to marginal zone lymphoma. Using a case-control approach, the risk of evolution of patients carrying MYD88 (L265P) was significantly higher than that of patients with wild-type MYD88 (odds ratio 4.7, 95% confidence interval 0.8 to 48.7, P = .047). These findings indicate that the allele-specific PCR we developed is a useful diagnostic tool for patients with WM or IgM-MGUS. In this latter condition, MYD88 (L265P) is associated with greater disease burden and higher risk of disease progression, and the mutation may therefore also represent a useful prognostic marker.

Clinical Relevance of Bone Marrow Fibrosis and CD34-Positive Cell Clusters in Primary Myelodysplastic Syndromes

PURPOSE We studied bone marrow (BM) histologic abnormalities in myelodysplastic syndromes (MDS) classified according to WHO criteria to determine their clinical correlates and prognostic value. PATIENTS AND METHODS Three hundred one consecutive patients were retrospectively evaluated for BM fibrosis and CD34 immunoreactivity. Marrow fibrosis was assessed following the European consensus guidelines. RESULTS Moderate to severe BM fibrosis was detected in 17% of cases and was associated with multilineage dysplasia (P = .001), high transfusion requirement (P < .001), and poor-risk cytogenetics (P = .007). CD34+ cell clusters were found in 23% of patients and were associated with WHO categories with excess of blasts (P < .001) and poor-risk cytogenetics (P = .001). In multivariable analysis, BM fibrosis and presence of CD34+ cell clusters had independent negative impact on overall survival (P < .001 and P = .019, respectively) and leukemia-free survival (P < .001 and P = .004, respectively). A hierarchical clustering analysis identified three subsets of patients with distinct clinical features. One cluster consisted mainly of patients with BM fibrosis, multilineage dysplasia, and high transfusion requirement; these individuals had lower overall survival and leukemia-free survival (P = .001 and P < .001, respectively). Within patients stratified according to International Prognostic Scoring System and WHO classification-based Prognostic Scoring System categories, BM fibrosis involved a shift to a one-step more advanced risk group. CONCLUSION BM fibrosis identifies a distinct subgroup of MDS with multilineage dysplasia, high transfusion requirement, and poor prognosis and represents an independent prognostic factor that may be useful in clinical decision making. Furthermore, the presence of CD34+ cell clusters is an independent risk factor for progression to acute leukemia.

Primary mediastinal B-cell lymphoma with sclerosis: an aggressive tumor with distinctive clinical and pathologic features.

PURPOSE To evaluate the clinical features of presentation, the morphologic and immunohistochemical pattern, the modality of spread, and the response to current treatments of patients with primary mediastinal B-cell lymphoma, a recently documented subtype of non-Hodgkins lymphoma (NHL). PATIENTS AND METHODS Thirty consecutive patients (14 males, 16 females; median age, 26 years) with primary mediastinal B-cell lymphoma with sclerosis were studied. RESULTS The clinical aspects were largely homogeneous: 93% presented with chest symptoms of a rapidly enlarging mass of the anterior mediastinum; the tumor was bulky in 73%, and superior vena cava syndrome (SVCS) was present in 57%. Also, patients without SVCS symptoms showed subclinical venacaval compression at computed tomographic (CT) scan, for a total incidence of caval obstruction of 80%. Intrathoracic extension to adjacent organs was seen in 47% of patients. Despite its invasive behavior, only four patients showed extrathoracic spread at diagnosis. In 23 cases, the tumor presented with morphologic features that resembled follicular center-cell lymphomas. In seven, the neoplastic population was composed mainly of centrocyte-like cells with abundant clear cytoplasm not referable to any known B-cell lymphoma subtype. All cases showed huge sclerosis. Of 29 patients assessable for response, 16 (55%) achieved a complete response (CR): five of 14 (36%) treated with cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP), and 11 of 15 (73%) treated with methotrexate plus leucovarin, doxorubicin, cyclophosphamide, vincristine, prednisone, and bleomycin (MACOP-B) or etoposide, doxorubicin, cyclophosphamide, vincristine, prednisone, and bleomycin (VACOP-B) (P = .047). We could identify no clinical, biologic, or histopathologic features significantly correlated with response. After chemotherapy, 14 of 16 remitters received consolidation radiotherapy to the mediastinum. At 3 years, the actuarial survival rate is 38% for all cases and 72% for remitters. None of the 13 patients who did not achieve CR responded to salvage treatments. CONCLUSION This study shows that primary mediastinal B-cell lymphoma with sclerosis is a distinctive subtype of NHL with unique clinicopathologic aspects and aggressive behavior. Prompt recognition and aggressive treatment may provide long survival in a good proportion of cases. However, a subset of patients is extremely refractory to first- and second-line treatment. Conventional prognostic factors seem inadequate to identify these very-poor-risk cases.

A prognostic model to predict survival in 867 World Health Organization–defined essential thrombocythemia at diagnosis: a study by the International Working Group on Myelofibrosis Research and Treatment

Diagnosis of essential thrombocythemia (ET) has been updated in the last World Health Organization (WHO) classification. We developed a prognostic model to predict survival at diagnosis, named IPSET (International Prognostic Score for ET), studying patients with WHO-defined ET. Age 60 years or older, leukocyte count ≥ 11 × 10(9)/L, and prior thrombosis significantly affected survival, by multivariable Cox regression. On the basis of the hazard ratio, we assigned 2 points to age and 1 each to leukocyte count and thrombosis. So, the IPSET model allocated 867 patients into 3 risk categories with significantly different survival: low (sum of points = 0; median survival not reached), intermediate (sum = 1-2; median survival 24.5 years), and high (sum = 3-4, median survival 13.8 years). The IPSET model was further validated in 2 independent cohorts including 132 WHO-defined ET and 234 Polycythemia Vera Study Group-defined ET patients. The IPSET model was able to predict the occurrence of thrombosis, and not to predict post-ET myelofibrosis. In conclusion, IPSET, based on age ≥ 60 years, leukocyte count ≥ 11 × 10(9)/L, and history of thrombosis allows prognostic assessment of WHO-defined ET and the validation process makes IPSET applicable in all patients phenotypically appearing as ET.