Biomedical subjects

Rebecca F McClure

Publications and source records attributed to Rebecca F McClure.

14 recordsLinked to original sources

PubMed2006

MPL515 mutations in myeloproliferative and other myeloid disorders: a study of 1182 patients.

Recently, a gain-of-function MPL mutation, MPLW515L, was described in patients with JAK2V617F-negative myelofibrosis with myeloid metaplasia (MMM). To gain more information on mutational frequency, disease specificity, and clinical correlates, genomic DNA from 1182 patients with myeloproliferative and other myeloid disorders and 64 healthy controls was screened for MPL515 mutations, regardless of JAK2V617F mutational status: 290 with MMM, 242 with polycythemia vera, 318 with essential thrombocythemia (ET), 88 with myelodysplastic syndrome, 118 with chronic myelomonocytic leukemia, and 126 with acute myeloid leukemia (AML). MPL515 mutations, either MPLW515L (n = 17) or a previously undescribed MPLW515K (n = 5), were detected in 20 patients. The diagnosis of patients with mutant MPL alleles at the time of molecular testing was de novo MMM in 12 patients, ET in 4, post-ET MMM in 1, and MMM in blast crisis in 3. Six patients carried the MPLW515L and JAK2V617F alleles concurrently. We conclude that MPLW515L or MPLW515K mutations are present in patients with MMM or ET at a frequency of approximately 5% and 1%, respectively, but are not observed in patients with polycythemia vera (PV) or other myeloid disorders. Furthermore, MPL mutations may occur concurrently with the JAK2V617F mutation, suggesting that these alleles may have functional complementation in myeloproliferative disease.

Adult↗

PubMed2006

Tumor suppressor p16 methylation in multiple myeloma: biological and clinical implications.

The biological and clinical implications of p16 gene methylation in multiple myeloma (MM) are still unclear despite previous studies. In this comprehensive study, using methylation-specific PCR (MS-PCR), we show that p16 methylation is relatively common and occurs in monoclonal gammopathy of undetermined significance (MGUS; n=17), smoldering multiple myeloma (SMM; n=40), and MM (n=522) at a prevalence of 24%, 28%, and 34%, respectively. However, p16 methylation does not appear to affect gene expression level. In a large cohort of patients with long-term follow-up information (n=439), there was no difference in overall survival between patients with or without p16 methylation. We also found no association between p16 methylation and the main cytogenetic categories, although it was more common among patients with 17p13.1 deletions (p53 locus), a genetic progression event in MM. In addition, p16 methylation has no apparent effect on the cycle because there was also no difference in the plasma cell labeling index (a direct measurement of proliferation) between patients with and without p16 methylation. Our results question a major role for p16 methylation in the oncogenesis of the PC neoplasm, and we now believe p16 methylation may be a marker for overall epigenetic changes associated with disease progression, with no obvious direct biological or clinical consequences.

Cell Cycle↗

PubMed2006

Lenalidomide therapy in myelofibrosis with myeloid metaplasia.

We present results of 2 similarly designed but separate phase 2 studies involving single-agent lenalidomide (CC-5013, Revlimid) in a total of 68 patients with symptomatic myelofibrosis with myeloid metaplasia (MMM). Protocol treatment consisted of oral lenalidomide at 10 mg/d (5 mg/d if baseline platelet count < 100 x 10(9)/L) for 3 to 4 months with a plan to continue treatment for either 3 or 24 additional months, in case of response. Overall response rates were 22% for anemia, 33% for splenomegaly, and 50% for thrombocytopenia. Response in anemia was deemed impressive in 8 patients whose hemoglobin level normalized from a baseline of either transfusion dependency or hemoglobin level lower than 100 g/L. Additional treatment effects in these patients included resolution of leukoerythroblastosis (4 patients), a decrease in medullary fibrosis and angiogenesis (2 patients), and del(5)(q13q33) cytogenetic remission accompanied by a reduction in JAK2(V617F) mutation burden (1 patient). Grade 3 or 4 adverse events included neutropenia (31%) and thrombocytopenia (19%). We conclude that lenalidomide engenders an intriguing treatment activity in a subset of patients with MMM that includes an unprecedented effect on peripheral blood and bone marrow abnormalities.

Administration, Oral↗

PubMed2006

The JAK2 V617F mutation is absent in patients with erythrocytosis due to high oxygen affinity hemoglobin variants.

High oxygen affinity hemoglobin (Hb) variants are an important and well characterized cause of secondary erythrocytosis. We tested 22 patients with high oxygen affinity beta chain variants for the presence of the JAK2 V617F mutation that has been reported in chronic myeloproliferative disorders, particularly polycythemia vera. All specimens showed the absence of this mutation. This observation contributes to the overall clinical specificity of the JAK2 V617F mutation.

DNA Mutational Analysis↗

PubMed2006

Concurrent MPL515 and JAK2V617F mutations in myelofibrosis: chronology of clonal emergence and changes in mutant allele burden over time.

MPLW515L/K and JAK2V617F can co-exist in myelofibrosis with myeloid metaplasia (MMM). The chronology of clonal emergence was studied in three such cases using serially stored bone marrow. At diagnosis, a major MPL515 mutant clone was accompanied by a minor JAK2V617F clone in all three instances. At 25 time points over a period of 4-8 years, allele burden fluctuated but remained high for MPLW515L/K and low for JAK2V617F. We conclude that MPLW515L/K and JAK2V617F are both early events in MMM and allele burden, rather than the mere presence of these mutations, might be relevant to phenotypic variation in myeloproliferative disorders.

Alleles↗

PubMed2006

Essential thrombocythemia beyond the first decade: life expectancy, long-term complication rates, and prognostic factors.

OBJECTIVE: To describe the long-term natural history of essential thrombocythemia (ET) in terms of life expectancy, risk of disease transformation Into a more aggressive myeloid disorder, and prognostic factors for both survival and disease complications. PATIENTS AND METHODS: The study population consisted of a consecutive cohort of patients seen at the Mayo Clinic In Rochester, Minn, in whom a diagnosis of ET was established before 1992, thus allowing a minimum of 10 years of potential follow-up. The conventional criteria-based diagnosis was confirmed by bone marrow biopsy in all Instances. RESULTS: A total of 322 patients were studied (median age, 54 years; median follow-up, 13.6 years). With a median survival time of 18.9 years, survival in the first decade of disease was similar to that of the control population (risk ratio, 0.72; 95% confidence interval, 0.50-0.99) but became significantly worse thereafter (risk ratio, 2.21; 95% confidence Interval, 1.74-2.76). Multivariable analysis identified age at diagnosis of 60 years or older, leukocytosis, tobacco use, and diabetes mellitus as Independent predictors of poor survival. A 2-variable model based on an age cutoff of 60 years and leukocyte count of 15 x 10(9)/L resulted in 3 risk groups with significant difference in survival. In addition, age at diagnosis of 60 years or older, leukocytosis, and history of thrombosis were independent predictors of major thrombotic events. The risk of leukemic or any myeloid disease transformation was low in the first 10 years (1.4% and 9.1%, respectively) but increased substantially in the second (8.1% and 28.3%, respectively) and third (24.0% and 58.5%, respectively) decades of the disease. CONCLUSION: Life expectancy in patients with ET is significantly worse than that of the control population. Leukocytosis is identified as a novel independent risk factor for both inferior survival and thrombotic events.

Adolescent↗

PubMed2006

MPL W515 and JAK2 V617 mutation analysis in patients with refractory anemia with ringed sideroblasts and an elevated platelet count.

Discovery of a constitutively activating point mutation of the Janus kinase 2 (JAK2) receptor-associated tyrosine kinase in patients with polycythemia vera (PV) and other BCR/ABL-negative myeloproliferative disorders prompted many groups around the world to examine diverse subsets of patients with myeloid diseases for the prevalence of the JAK2 V617F mutation and its clinical and pathological associations.

Aged, 80 and over↗

PubMed2005

The JAK2 V617F activating tyrosine kinase mutation is an infrequent event in both "atypical" myeloproliferative disorders and myelodysplastic syndromes.

A somatic mutation in the JH2 autoinhibitory domain of the Janus kinase 2 (JAK2) tyrosine kinase was recently described in polycythemia vera, essential thrombocythemia, and myelofibrosis with myeloid metaplasia. The prevalence of this mutation in either "atypical" myeloproliferative disorders (MPDs) or the myelodysplastic syndromes (MDSs) is unknown. Bone marrow-derived genomic DNA from 245 patients--119 with chronic myelomonocytic leukemia (CMML), 101 with MDS, 11 with hypereosinophilic syndrome (HES), 8 with systemic mastocytosis (SM), and 6 with chronic neutrophilic leukemia (CNL)--was screened for the JAK2 V617F mutation. A mutant allele was detected in 11 patients: 3 with CMML (3%), 5 with MDS (5%), 2 with SM, and 1 with CNL. Interestingly, one of the patients with SM and the patient with CNL with JAK2 V617F had a history of lymphoma, and this patient with SM also had associated myelofibrosis and CMML. The current observation strengthens the specific association between JAK2 V617F and classic MPD, but also suggests an infrequent occurrence in other myeloid disorders.

Adult↗

PubMed2005

Multiple myeloma presenting initially as a solitary pleural effusion later complicated by malignant plasmacytic ascites.

A pleural effusion is a rare presenting feature of multiple myeloma and can be a complication of myelomatous ascites as well. An additional unique feature of our case includes the finding of a normal bone marrow at the time of presentation despite the aggressive course of the disease. To the best of our knowledge after an extensive medical literature review, this case is the first one of multiple myeloma presenting with a plasmacytic pleural effusion, a negative bone marrow, and a late complication of plasmacytic ascites. Involvement of serous cavities in myeloma carries a poor prognosis, and there is currently no standard effective treatment regimen.

Ascites↗

PubMed2005

Adult B-cell lymphomas with burkitt-like morphology are phenotypically and genotypically heterogeneous with aggressive clinical behavior.

Adult, de novo B-cell lymphomas meeting the WHO morphologic criteria for atypical Burkitt/Burkitt-like lymphoma cause diagnostic difficulty for pathologists because the genetic and clinical characteristics of this group of lymphomas have not been clearly defined. Thirty-one such lymphomas, designated as Burkitt-like lymphomas (BLL), were selected based on morphologic features and evaluated for immunophenotype, MYC and BCL2 status, and clinical features. Nine childhood Burkitt lymphomas (BL) and 87 adult, de novo diffuse large B-cell lymphomas (DLBL) were similarly evaluated for comparison. The BL group demonstrated uniform characteristics: all had Burkitt lymphoma morphology, an identical immunophenotype (positive for CD20, CD10, bcl-6, CD43, and p53; negative for CD138, CD23, bcl-2), high MIB-1 positivity, IGH/MYC translocation, no IGH/BCL2 translocation, and all patients were alive at the last follow-up. The BLL and DLBL groups were heterogeneous. Burkitt-like morphology alone correlated with decreased survival. IGH/MYC or IGL/MYC fusion was identified in 11 of 27 (41%) BLL and 4 of 76 (5%) DLBL and was associated with decreased survival in both groups. MIB-1 positivity did not correlate with morphology, MYC abnormalities, or survival. We propose that adult B-cell lymphomas with BLL morphology are a phenotypically and genetically heterogeneous group of aggressive lymphomas, biologically distinct from childhood BL. Until biologically accurate subgroups within this morphologically defined group are identified, it is appears that both recognition of BLL morphology and direct evaluation for the presence of MYC fusion to immunoglobulin genes are important for identification of adult patients with poorer prognosis than those with DLBL.

Adolescent↗

PubMed2005

JAK2 mutation in essential thrombocythaemia: clinical associations and long-term prognostic relevance.

Clinical correlates and long-term prognostic relevance of the JAK2(V617F) mutation was studied in 150 patients with essential thrombocythaemia (ET) from a single institution and followed for a median of 11.4 years. During this period, thrombotic complications were documented in 62 patients (41.3%) and transformation into acute myeloid leukaemia (AML), polycythaemia vera (PV), or myelofibrosis with myeloid metaplasia (MMM) occurred in 4 (2.7%), 8 (5.3%), and 15 (10%) patients, respectively. JAK2(V617F) was detected in either archived bone marrow or blood cells from 73 patients (48.7%) but none were homozygous for the mutant allele. Parameters at diagnosis that were significantly associated with the presence of JAK2(V617F) included advanced age and higher counts of both haemoglobin and leucocytes. During follow-up, patients with the mutation were more likely to transform into PV but the incidences of AML, MMM, or thrombotic events were similar between patients with and without the mutation. Multivariate analysis identified advanced age, higher haemoglobin level, and thrombosis history but not the presence of JAK2(V617F) as independent predictors of inferior survival. Therefore, although the presence of JAK2(V617F) in ET appears to promote a PV phenotype, it might not carry treatment-relevant information.

Adolescent↗

PubMed2004

Histiocytes containing immunoglobulin crystals in the urine of a patient with IgA kappa plasmacytoma of the bladder.

Exfoliative cytology specimens from patients with plasma cell dyscrasias are rarely diagnostic, though there are reports of neoplastic plasma cells observed in pleural fluid and urine. Immunoglobulin concretions or crystals associated with neoplastic plasma cell populations have been well described. These crystals may be found within plasma cell nuclei or cytoplasm, extracellularly, or within cells of histiocytic lineage where they are presumably derived by phagocytosis. To the best of our knowledge, this is the first report of immunoglobulin crystals within histiocytes in the urine of a patient with plasmacytoma. A 61-year-old male underwent routine cystoscopy and urine collection to evaluate hematuria. The bladder biopsy demonstrated IgA kappa-producing plasmacytoma. Urine cytopsin preparations did not contain plasma cells, but there were histiocytic cells with degenerative nuclei and eccentrically located cytoplasmic spherical refractile hyaline crystals thought to be immunoglobulin crystals. This was supported by immunocytochemical staining.

Crystallization↗

PubMed2004

Agnogenic myeloid metaplasia with pleural extramedullary leukemic transformation.

Agnogenic myeloid metaplasia (AMM) is one of the myeloproliferative disorders, and is usually accompanied by extramedullary hematopoiesis (EMH) in various organs, mainly in the liver, spleen and lymph nodes. Extramedullary hematopoiesis and/or leukemic transformation of EMH in the pleura is a rare occurrence and is usually asymptomatic. Pleural involvement is usually diagnosed on postmortem examination. Herein we describe a 71-year-old man with newly diagnosed agnogenic myeloid metaplasia who was evaluated for progressively worsening dyspnea, pulmonary hypertension and bilateral pleural effusions. EMH involving the lungs and pleura was suspected. A sulfur colloid technetium 99m bone marrow scan performed to detect extramedullary hematopoiesis was negative. The diagnostic thoracentesis yielded bloody fluid that contained a large population of myeloblasts, indicating pleural leukemic transformation. The patient received 100 cGy to the whole lung for treatment of pulmonary hypertension due to EMH. This was followed by 1500 cGy total dose of radiation to the left lung for pleural extramedullary leukemic transformation. Pleural effusions resolved and repeat echocardiography showed reduction of the pulmonary artery pressure. Three months later he had leukemic transformation involving the skin and lymph nodes. Four months after radiation therapy, he had full-blown acute myeloid leukemia. He received 2 cycles of Gemtuzumab ozogamicin (Mylotarg), allopurinol and hydroxyurea. Three months after initiation of chemotherapy, he deteriorated and received salvage chemotherapy of prednisone, VP-16 and imatinib mesylate (Gleevec). He was hospitalized for neutropenic fever and was diagnosed to have pulmonary aspergillosis. He died of multisystem failure 8 1/2 months after being diagnosed with AMM.

Aged↗

PubMed2002

A new method to extract nuclei from paraffin-embedded tissue to study lymphomas using interphase fluorescence in situ hybridization.

Fluorescence in situ hybridization (FISH) is difficult to accomplish using thin-sections of paraffin-embedded lymphoid tissue because of the high cellularity and truncated cells that interfere with accurate scoring of individual nuclei. We modified and tested a new technique to isolate individual nuclei from tissue cores of paraffin-embedded tissue processed with xylene, proteinase K, citric acid, and pepsin. The efficacy of this method to study paraffin-embedded tissue was investigated in six normal lymph nodes or tonsils and 32 malignant lymphomas including five mantle cell, five follicular, five Burkitt, five extranodal marginal zone lymphomas of mucosa-associated lymphoid tissue, five anaplastic large-cell, and seven diffuse large B-cell. Fusion of CCND1 and IgH, BCL2 and IgH, c-myc and IgH, and MALT1 and API2 were detected using probes with a dual-fusion FISH strategy. Anomalies involving ALK and BCL6 were detected using break-apart FISH probes. FISH studies were successful for each of the 38 specimens. Chromosome anomalies were detected in each malignant specimen, but not in the normal lymphoid tissue. The correct chromosome anomaly was detected in 22 of 22 specimens with genetic abnormalities that were established by other genetic techniques. This FISH technique is useful to detect chromosome anomalies with high sensitivity and specificity in paraffin-embedded tissue and may provide important diagnostic and prognostic genetic information.

Burkitt Lymphoma↗