Expression of TEL-JAK2 in primary human hematopoietic cells drives erythropoietin-independent erythropoiesis and induces myelofibrosis in vivo.

Activation of JAK2 by chromosomal translocation or point mutation is a recurrent event in hematopoietic malignancies, including acute leukemias and myeloproliferative disorders. Although the effects of activated JAK2 signaling have been examined in cell lines and murine models, the functional consequences of deregulated JAK2 in the context of human hematopoietic cells are currently unknown. Here we report that expression of TEL-JAK2, a constitutively active variant of the JAK2 kinase, in lineage-depleted human umbilical cord blood cells results in erythropoietin-independent erythroid differentiation in vitro and induces the rapid development of myelofibrosis in an in vivo NOD/SCID xenotransplantation assay. These studies provide functional evidence that activated JAK2 signaling in primitive human hematopoietic cells is sufficient to drive key processes implicated in the pathophysiology of polycythemia vera and idiopathic myelofibrosis. Furthermore, they describe an in vivo model of myelofibrosis initiated with primary cells, highlighting the utility of the NOD/SCID xenotransplant system for the development of experimental models of human hematopoietic malignancies.

Effect of premedication guidelines and leukoreduction on the rate of febrile nonhaemolytic platelet transfusion reactions.

Platelet transfusion reactions were prospectively studied in haematology/oncology patients at five university teaching hospitals over three consecutive summers. The initial summer study provided baseline information on the use of premedications and the rate of platelet transfusion reactions (fever, chills, rigors and hives). Most (73%) platelet recipients were premedicated and 30% (95% CI 28-33%) of transfusions were complicated by reactions. The second study followed implementation of guidelines for premedicating platelet transfusions. Despite a marked reduction in premedication (50%), there was little change in the platelet transfusion reaction rate, 26% (95% CI 24-29%), or the type of reactions. The third study followed implementation of prestorage platelet leukoreduction while maintaining the premedication guidelines. The reaction rate decreased to 19% (95% CI 17-22%). For nonleukoreduced platelets, there was a statistically significant association between the platelet age and reaction rate (P = 0.04). For leukoreduced platelets, there was no statistically significant association between platelet age and reaction rate (P = 0.5). Plasma reduction of nonleukoreduced platelet products also reduced the reaction rate. These prospective studies document a high rate of platelet transfusion reactions in haematology/oncology patients and indicate premedication use can be reduced without increasing the reaction rate. Prestorage leukoreduction and/or plasma reduction of platelet products reduces but does not eliminate febrile nonhemolytic platelet transfusion reactions.

Flow-cytometry-enhanced fine-needle aspiration biopsy of the spleen.

OBJECTIVE: Flow cytometry is proving useful in the evaluation of lymphoproliferative disorders. In a case series, the authors investigated the safety of cross-sectional fine-needle aspiration biopsy of the spleen under sonographic guidance, and the usefulness of flow cytometry in analysis of biopsy samples. METHODS: Five patients underwent fine-needle biopsy with freehand sonographic guidance. Samples were analyzed on a flow cytometer. RESULTS: Through cytologic examination enhanced by flow cytometry, 2 cases of lymphoma, 1 case of metastatic transitional cell carcinoma, and 1 case of focal splenic hemangioma were diagnosed. Normal lymphocytes were demonstrated in 1 case, in which long-term follow-up of splenomegaly showed that this was related to cirrhosis and portal hypertension in a patient with a history of treated non-Hodgkin's lymphoma. CONCLUSION: Flow-cytometry-enhanced fine-needle aspiration of the spleen is a safe and useful tool for the interventional radiologist. In our institution, it evolved as the result of effective teamwork between diagnostic radiologists and pathologists. Flow cytometry promises to be increasingly useful in the diagnosis and management of lymphoproliferative diseases.

In vivo evidence that caspase-3 is required for Fas-mediated apoptosis of hepatocytes.

Caspase-3 is essential for Fas-mediated apoptosis in vitro. We investigated the role of caspase-3 in Fas-mediated cell death in vivo by injecting caspase-3-deficient mice with agonistic anti-Fas Ab. Wild-type controls died rapidly of fulminant hepatitis, whereas the survival of caspase-3-/- mice was increased due to a delay in hepatocyte cell death. Bcl-2 expression in the liver was dramatically decreased in wild-type mice following anti-Fas injection, but was unchanged in caspase-3-/- mice. Hepatocytes from anti-Fas-injected wild-type, but not caspase-3-/-, mice released cytochrome c into the cytoplasm. Western blotting confirmed the lack of caspase-3-mediated cleavage of Bcl-2. Presumably the presence of intact Bcl-2 in caspase-3-/- hepatocytes prevents the release of cytochrome c from the mitochondria, a required step for the mitochondrial death pathway. We also show by Western blot that Bcl-xL, caspase-9, caspase-8, and Bid are processed by caspase-3 in injected wild-type mice but that this processing does not occur in caspase-3-/- mice. This study thus provides novel in vivo evidence that caspase-3, conventionally known for its downstream effector function in apoptosis, also modifies Bcl-2 and other upstream proteins involved in the regulation of Fas-mediated apoptosis.

Isolated chloroma: the effect of early antileukemic therapy.

OBJECTIVE: To evaluate the effect of antileukemic chemotherapy administered at diagnosis on the survival of patients with isolated chloroma. DESIGN: Retrospective review of locally identified patients and analysis of cases from the medical literature. PATIENTS: The records of all patients with isolated chloroma identified at three teaching hospitals in Toronto between 1980 and 1994 were reviewed. A MEDLINE search was done to identify all cases of isolated chloroma reported in the English-language medical literature. Patients with a previous known hematologic disorder were excluded. MEASUREMENTS: The effect of therapy on 1) the interval between diagnosis of chloroma and diagnosis of acute myeloid leukemia and 2) survival was determined. RESULTS: 7 local patients and 83 published cases were identified, for a total of 90 evaluable patients. For the entire group, the median time to the diagnosis of acute myeloid leukemia was 9 months, and median survival was 22 months. Chemotherapy was administered to 49 patients (54%) at diagnosis of chloroma. Significantly fewer patients treated with chemotherapy subsequently developed acute myeloid leukemia (41% compared with 71%; P = 0.001). Survival was longer in patients treated with chemotherapy (> 50% alive with a median follow-up of 25 months compared with a median survival of 13 months for those initially untreated; P = 0.001). Multivariate analysis showed that neither local radiotherapy nor surgery had an effect on survival. CONCLUSIONS: Administration of antileukemic chemotherapy at diagnosis of chloroma is associated with a significantly lower probability of developing acute myeloid leukemia and with longer survival.

Non-Hodgkin's lymphoma of the thyroid gland: prognostic factors and treatment outcome. The Princess Margaret Hospital Lymphoma Group.

PURPOSE: Non-Hodgkin's lymphoma presenting in the thyroid gland is uncommon. A review of the Princess Margaret Hospital experience was performed to assess treatment outcome and prognostic factors in this rare extranodal presentation of localized lymphoma. METHODS AND MATERIALS: Fifty-two patients treated at the PMH between 1978 and 1986 were identified and their records reviewed retrospectively. Staging procedures revealed 16 patients with Stage I, 28 with Stage II, and eight with Stages III or IV disease. Five patients were treated on a protocol designed for anaplastic carcinoma of thyroid and they were excluded from detailed analysis. Of 39 patients with Stages I and II disease, 18 were treated with radiotherapy alone, three chemotherapy alone, and 18 combined modality therapy. Combined modality therapy was used mainly in patients with large tumor bulk. RESULTS: The overall 5-year actuarial survival and cause-specific survival were 56% and 64%, respectively. The overall relapse-free rate was 61% at 5 years. Among the 39 patients with Stages I and II disease, the 5-year actuarial survival, cause-specific survival, and relapse-free rate were 64%, 73%, and 66%, respectively. There were no significant differences in outcome between those treated with radiotherapy alone and those treated with combined modality therapy (cause-specific survival: p = 0.25, relapse: p = 0.06). A univariate analysis showed that the only variable to reach statistical significance was tumor bulk. Age was marginally significant while stage and histology were not statistically significant, possibly due to the fairly homogeneous distribution of patients in each of these variables. Patients with progression or relapse of lymphoma after initial treatment frequently died of disease. Isolated gastrointestinal relapses occurred in three cases, representing 27% of all relapses. CONCLUSION: Based on the above results, we recognize that the majority of patients with localized thyroid lymphoma require combined modality therapy and we recommend radiotherapy alone only for a small, select group of patients with Stage I disease and small tumor bulk.

B-cell lymphoma presenting as a midfacial necrotizing lesion.

A case of midfacial necrotizing lesion (midline nonhealing granuloma) is reported. Paraffin- and frozen-section immunocytochemistry suggested a tumor of B-cell lineage and was confirmed by Southern blot analysis that disclosed an immunoglobulin heavy chain gene rearrangement with no evidence of T-cell receptor genetic aberration. The tumor was of B-cell lineage despite the tumor site and the angiocentric pattern, which are typically seen with peripheral T cell lymphoma with this presentation.

Analysis of supradiaphragmatic clinical stage I and II Hodgkin's disease treated with radiation alone.

Patients with clinical Stage I and II Hodgkin's disease have been managed at the Princess Margaret Hospital for over 20 years, without the use of routine staging laparotomy. Our experience identified as adverse prognostic factors presence of a large mediastinal mass, B symptoms, and advanced age in presence of unfavorable histology (20). We had suggested previously that the use of extended field radiation therapy (XRT) was associated with a lower risk of relapse than involved field XRT or mantle XRT. There has been a trend over the past decade to select those patients with favorable prognostic factors for treatment with XRT alone and to use mantle plus upper abdominal XRT (extended field XRT) to treat them. A retrospective study of patients with clinical Stage I and II Hodgkin's disease treated at the Princess Margaret Hospital between 1978 and 1986 was conducted to determine the impact of patient selection and extended field radiation on outcome. The study involved 250 patients with supradiaphragmatic disease selected for treatment with radiation alone on the absence of adverse prognostic factors. Radiation techniques included involved field radiation in selected patients (those with upper neck involvement), mantle radiation in the earlier years, and mantle plus upper abdominal radiation in the later years of the study. Actuarial survival was 83.3% at 8 years; cause-specific survival was 90.1% and the relapse-free rate 71.6%. Local tumor control was 94.6%; only two patients had true infield failure. Multivariate analysis showed that significant prognostic factors included age, histology, and erythrocyte sedimentation rate. Extent of the radiation treatment volume was significant and influenced the risk of relapse, particularly out-of-field relapse, independently of other factors. A dose of 35 Gy was found to be sufficient for control of clinical disease. This study validated a previously developed model for the selection of clinically staged patients with Stage I and II Hodgkin's disease for treatment with radiation alone. Careful selection of these patients can yield excellent results without requiring that staging laparotomy be routinely performed or the use of systemic chemotherapy as the initial treatment.

Outcome analysis of localized gastrointestinal lymphoma treated with surgery and postoperative irradiation.

One hundred thirteen patients with localized gastrointestinal lymphoma treated by surgery and postoperative irradiation between 1967 and 1985 were reviewed. At 15 years, actuarial survival of this group was 40.6%, with a cause-specific survival of 69.2% and a relapse-free rate of 64%. Two-thirds of relapses occurred at distant sites. In Stage IA and IIA patients with no residuum or with positive resection margins, (N = 90) only site of involvement and stage predicted for relapse. Age, histologic subtype group, and depth of bowel wall invasion did not affect relapse risk. In the very favorable group (Stage IA, IIA, no residuum or microscopic residuum), 8.4% of patients with stomach lymphoma relapsed compared to 25% of patients with small bowel lymphoma. The risk of early relapse was higher in those with Stage IIA small bowel lymphoma than those with Stage IA small bowel lymphoma. We continue to recommend adjuvant abdominal irradiation for patients with Stage IA, IIA completely resected stomach lymphoma and Stage IA completely resected small bowel lymphoma. We recommend combined modality therapy for patients with completely resected Stage IIA small bowel lymphoma and all other localized gastrointestinal lymphoma where visible residual disease is present.

Pulmonary tumor embolism: a critical review of clinical, imaging, and hemodynamic features.

Pulmonary tumor embolism is a common finding at autopsy but is generally perceived as a difficult diagnosis to make ante mortem. After a retrospective review of 164 reported cases of pulmonary tumor embolism, we identified a typical profile of clinical, laboratory, and imaging features that may permit confident clinical diagnosis in most patients with this condition. The clinical features include a documented or suspected underlying malignancy, acute to subacute onset of dyspnea, and signs of cor pulmonale. Supportive laboratory features are hypoxemia or increased alveolar-arterial oxygen gradient, and invasive or noninvasive evidence of pulmonary artery hypertension. Typical imaging findings are normal chest radiographs; multiple, subsegmental, peripheral perfusion defects on ventilation-perfusion lung scans; and delayed filling with or without subsegmental filling defects but without a thrombus on pulmonary angiogram. Radiolabeled monoclonal antibody imaging and pulmonary microvascular cytology sampling techniques are promising diagnostic tests for early diagnosis of pulmonary tumor embolism.

Hematopoietic cell surface markers on metastatic small cell carcinoma detected with monoclonal antibodies.

Using a panel of monoclonal antibodies, cells from lymph node biopsies have been examined in three patients with small cell carcinoma presenting with cervical lymphadenopathy. Two patients had small (oat) cell carcinoma of the lung; in the third patient, a primary tumor was not found. Two lymph node biopsies showed typical small (oat) cell carcinoma, and one was an intermediate cell variant; in the last, lung biopsy showed small (oat) cell carcinoma. Electron microscopy demonstrated desmosomes in all three tumors. In each case, lymph node cell suspensions were examined by indirect immunofluorescence with the use of a panel of monoclonal antibodies to antigens usually associated with lymphoid or myeloid cells. In two of the three cases malignant cells were positive with the lymphoid marker BA-2; in two cases malignant cells were positive with OK1a1, a marker for the Ia-like antigen (HLA-DR); and in one case malignant cells were positive with My-1. Caution is needed in the interpretation of cell surface marker studies in the differential diagnosis of small round cell tumors.