Dnmt3a regulates myeloproliferation and liver-specific expansion of hematopoietic stem and progenitor cells.

DNA methyltransferase 3A (DNMT3A) mutations are observed in myeloid malignancies, including myeloproliferative neoplasms (MPN), myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML). Transplantation studies have elucidated an important role for Dnmt3a in stem cell self-renewal and in myeloid differentiation. Here, we investigated the impact of conditional hematopoietic Dnmt3a loss on disease phenotype in primary mice. Mx1-Cre-mediated Dnmt3a ablation led to the development of a lethal, fully penetrant MPN with myelodysplasia (MDS/MPN) characterized by peripheral cytopenias and by marked, progressive hepatomegaly. We detected expanded stem/progenitor populations in the liver of Dnmt3a-ablated mice. The MDS/MPN induced by Dnmt3a ablation was transplantable, including the marked hepatomegaly. Homing studies showed that Dnmt3a-deleted bone marrow cells preferentially migrated to the liver. Gene expression and DNA methylation analyses of progenitor cell populations identified differential regulation of hematopoietic regulatory pathways, including fetal liver hematopoiesis transcriptional programs. These data demonstrate that Dnmt3a ablation in the hematopoietic system leads to myeloid transformation in vivo, with cell-autonomous aberrant tissue tropism and marked extramedullary hematopoiesis (EMH) with liver involvement. Hence, in addition to the established role of Dnmt3a in regulating self-renewal, Dnmt3a regulates tissue tropism and limits myeloid progenitor expansion in vivo.

FoxO1-dependent induction of acute myeloid leukemia by osteoblasts in mice.

Osteoblasts, the bone forming cells, affect self-renewal and expansion of hematopoietic stem cells (HSCs), as well as homing of healthy hematopoietic cells and tumor cells into the bone marrow. Constitutive activation of ß-catenin in osteoblasts is sufficient to alter the differentiation potential of myeloid and lymphoid progenitors and to initiate the development of acute myeloid leukemia (AML) in mice. We show here that Notch1 is the receptor mediating the leukemogenic properties of osteoblast-activated ß-catenin in HSCs. Moreover, using cell-specific gene inactivation mouse models, we show that FoxO1 expression in osteoblasts is required for and mediates the leukemogenic properties of ß-catenin. At the molecular level, FoxO1 interacts with ß-catenin in osteoblasts to induce expression of the Notch ligand, Jagged-1. Subsequent activation of Notch signaling in long-term repopulating HSC progenitors induces the leukemogenic transformation of HSCs and ultimately leads to the development of AML. These findings identify FoxO1 expressed in osteoblasts as a factor affecting hematopoiesis and provide a molecular mechanism whereby the FoxO1/activated ß-catenin interaction results in AML. These observations support the notion that the bone marrow niche is an instigator of leukemia and raise the prospect that FoxO1 oncogenic properties may occur in other tissues.

Expert second-opinion pathology review of lymphoma in the era of the World Health Organization classification.

BACKGROUND: The World Health Organization (WHO) classification of hematologic malignancies, published in 2000, was designed to improve diagnostic accuracy by incorporating the latest in scientific understanding. The impact of the WHO classification on the frequency of diagnostic discrepancy in lymphoma is unknown. METHODS: We reviewed all second-opinion pathology of lymphoma at our National Cancer Institute-designated Comprehensive Cancer Center (NCI-CCC) from January to June 2001 and from January to June 2006. Discrepancies between submitted and second-opinion diagnoses were scored based upon an a priori grading schema. RESULTS: Major diagnostic revision was rendered in 65 of 365 cases (17.8%) in 2001 and 58 of 354 (16.4%) in 2006 (P=NS). Including cases reviewed and revised beforehand at another NCI-CCC, rates of major diagnostic revision were 21.4% and 18.6%, respectively (P=NS). Discrepancy rates varied by diagnosis, from Hodgkin lymphoma (10%) to Burkitt's lymphoma (75%). No association was seen for age, gender, race/ethnicity, biopsy type, or nature of referring center. CONCLUSIONS: Clinically meaningful diagnostic revision occurs frequently with expert pathology review for a diagnosis of lymphoma. Despite the WHO classification, rates of diagnostic revision at our institution in 2001 and 2006 did not differ significantly. Given the potential harm from misdiagnosis, expert hematopathology review should be considered the standard of care.

Prognostic impact of proliferative index determined by quantitative image analysis and the International Prognostic Index in patients with mantle cell lymphoma.

BACKGROUND: The proliferative index (PI) is a powerful prognostic factor in mantle cell lymphoma (MCL); however, its utility is hampered by interobserver variability. The mantle cell international prognostic index (MIPI) has been reported to have prognostic importance. In this study, we determined the prognostic value of the PI as determined by quantitative image analysis in MCL. PATIENTS AND METHODS: Eighty-eight patients with adequate tissue were included in this analysis. Patients were treated with one of two treatment programs: sequential therapy with high-dose therapy consolidation or radioimmunotherapy followed by combination chemotherapy with cyclophosphamide, doxorubicin, vincristine and prednisone. Patients were divided into four groups based on PI (<10%, 10%-29.9%, 30%-49.9%, and >50%), and outcomes were analyzed. RESULTS: Thirty percent was identified as the optimal cut-off for PI. By univariate analysis, intensive treatment and a low PI were associated with a superior progression-free survival (PFS); only PI was associated with overall survival. By multivariate analysis, both intensive treatment and PI correlated with PFS. The MIPI had no prognostic impact. CONCLUSIONS: PI is the most important prognostic factor in MCL. The cut-off of 30% is clinically meaningful and can be used to tailor the intensity of therapy in future clinical trials.

Molecular cytogenetic analysis of follicular lymphoma (FL) provides detailed characterization of chromosomal instability associated with the t(14;18)(q32;q21) positive and negative subsets and histologic progression.

We analyzed a cohort of 61 follicular lymphomas (FL) with an abnormal G-banded karyotype by spectral karyotyping (SKY) to better define the chromosome instability associated with the t(14;18)(q32;q21) positive and negative subsets of FL and histologic grade. In more than 70% of the patients, SKY provided additional cytogenetic information and up to 40% of the structural abnormalities were revised. The six most frequent breakpoints in both SKY and G-banding analyses were 14q32, 18q21, 3q27, 1q11-q21, 6q11-q15 and 1p36 (15-77%). SKY detected nine additional sites (1p11-p13, 2p11-p13, 6q21, 8q24, 6q21, 9p13, 10q22-q24, 12q11-q13 and 17q11-q21) at an incidence of >10%. In addition to the known recurring translocations, t(14;18)(q32;q21) [70%], t(3;14)(q27;q32) [10%], t(1;14)(q21;q32) [5%] and t(8;14)(q24;q32) [2%] and their variants, 125 non-IG gene translocations were identified of which four were recurrent within this series. In contrast to G-banding analysis, SKY revealed a greater degree of karyotypic instability in the t(14;18) (q32;q21) negative subset compared to the t(14;18)(q32;q21) positive subset. Translocations of 3q27 and gains of chromosome 1 were significantly more frequent in the former subset. SKY also allowed a better definition of chromosomal imbalances, thus 37% of the deletions detected by G-banding were shown to be unbalanced translocations leading to gain of genetic material. The majority of recurring (>10%) imbalances were detected at a greater (2-3 fold) incidence by SKY and several regions were narrowed down, notably at gain 2p13-p21, 2q11-q21, 2q31-q37, 12q12-q15, 17q21-q25 and 18q21. Chromosomal abnormalities among the different histologic grades were consistent with an evolution from low to high grade disease and breaks at 6q11-q15 and 8q24 and gain of 7/7q and 8/8q associated significantly with histologic progression. This study also indicates that in addition to gains and losses, non-IG gene translocations involving 1p11-p13, 1p36, 1q11-q21, 8q24, 9p13, and 17q11-q21 play an important role in the histologic progression of FL with t(14;18)(q32;q21) and t(3q27).

Dyskerin expression influences the level of ribosomal RNA pseudo-uridylation and telomerase RNA component in human breast cancer.

Dyskerin is a nucleolar protein, altered in dyskeratosis congenita, which carries out two separate functions, both fundamental for proliferating cells. One function is the pseudo-uridylation of ribosomal RNA (rRNA) molecules, necessary for their processing, and the other is the stabilization of the telomerase RNA component, necessary for telomerase activity. A significant feature of dyskeratosis congenita is an increased susceptibility to cancer; so far, however, no data have been reported on dyskerin changes in human tumours. Therefore, in this study, the distribution of dyskerin in a large series of human tumours from the lung, breast, and colon, as well as from B-cell lymphomas, was analysed by immunohistochemistry. Dyskerin proved never to be lost or delocalized outside the nucleolus. A quantitative analysis of dyskerin mRNA expression was then performed in 70 breast carcinomas together with the evaluation of telomerase RNA component levels and rRNA pseudo-uridylation. Dyskerin mRNA levels were highly variable and directly associated with both telomerase RNA component levels and rRNA pseudo-uridylation. Dyskerin gene silencing in the MCF-7 human breast carcinoma cell line reduced telomerase activity and rRNA pseudo-uridylation. Significantly, patients with low dyskerin expression were characterized by a better clinical outcome than those with a high dyskerin level. These data indicate that dyskerin is not lost in human cancers and that the levels of its expression and function are associated with tumour progression.

Results of a phase I/II trial adding carmustine (300 mg/m2) to melphalan (200 mg/m2) in multiple myeloma patients undergoing autologous stem cell transplantation.

Autologous stem cell transplantation (SCT) with high-dose melphalan (HDM, 200 mg/m2) is the most effective therapy for multiple myeloma. To determine the feasibility of combining carmustine (300 mg/m2) with HDM, we enrolled 49 patients with previously treated Durie-Salmon stage II/III myeloma (32M/17W, median age 53) on a phase I/II trial involving escalating doses of melphalan (160, 180, 200 mg/m2). The median beta2-microglobulin was 2.5 (0-9.3); marrow karyotypes were normal in 88%. The phase I dose-limiting toxicity was > or =grade 2 pulmonary toxicity 2 months post-SCT. Other endpoints were response rate and progression-free survival (PFS). HDM was safely escalated to 200 mg/m2; treatment-related mortality was 2% and > or =grade 2 pulmonary toxicity 10%. The complete (CR) and near complete (nCR) response rate was 49%. With a median post-SCT follow-up of 2.9 years, the PFS and overall survival (OS) post-SCT were 2.3 and 4.7 years. PFS for those with CR or nCR was 3.1 years while for those with stable disease (SD) it was 1.3 years (P=0.06). We conclude that carmustine can be combined with HDM for myeloma with minimal pulmonary toxicity and a high response rate.

Hematopoietic stem cell mobilization with intravenous melphalan and G-CSF in patients with chemoresponsive multiple myeloma: report of a phase II trial.

Multiple myeloma (MM) is an incurable hematologic malignancy for which autologous hematopoietic stem cell transplantation (HCT) is a standard therapy. The optimal method of stem cell mobilization is not defined. We evaluated intravenous melphalan (60 mg/m2), the most effective agent for MM, and G-CSF (10 microg/kg/day) for mobilization. End points were safety, adequacy of CD34+ collections, MM response, and contamination of stem cell components (SCC). In total, 32 patients were mobilized. There were no deaths or significant bleeding episodes; 14 patients (44%) required hospitalization for neutropenic fever. Median days of grade 3 or 4 neutropenia or thrombocytopenia were 7 (2-20) and 8 (3-17). Median mobilization days, CD34+ cells/kg and total leukaphereses were 16 (12-30), 12.1 million (2.6-52.8), and 2 (1-5) respectively. Four patients (12.5 %) failed to achieve the target of 4 million CD34+ cells/kg in five leukaphereses. Reduction in myeloma was seen in 11 patients (34%) with 3 (9%) achieving complete response; 15 (47%) maintained prior responses. Estimated MM contamination per SCC (N=48) was 0.0009% (range 0-0.1) and 0.21 x 10(4) cells per kg (range 0-41.2). Increased contamination was associated with increased patient age. This strategy for mobilization is feasible, frequently requires hospitalization and transfusion, and controls disease in most patients.

CD20-negative large-cell lymphoma with plasmablastic features: a clinically heterogenous spectrum in both HIV-positive and -negative patients.

BACKGROUND: Plasmablastic lymphoma (PBL) has been described as a rapidly progressive and almost invariably fatal CD20- VS38c+ diffuse large-cell lymphoma with plasmablastic features, almost exclusively involving the jaw and oral mucosa in HIV-positive patients. METHODS: From 2001 to 2003 we evaluated 12 men with PBL, and report the pathology, clinical findings, treatment and outcome. Six of 12 were HIV-positive while among the others, one was post-renal transplant, one had ulcerative colitis and four had no known immunodeficiency. RESULTS: Tumor growth pattern, in general, showed cohesiveness and a starry-sky pattern; the morphology varied from typical plasmablastic to centroblastic cells. Partial immunophenotypes were (+/total): CD138, 11 of 12 (91.7%); MIB1 10 of 11 (4+, range 75-95%); p63/VS38c, nine of 10 (90%); EBV, eight of 11 (73%); LCA(CD45), two of 12 (16.7%); HHV8/LANA, zero of 10; ALK, zero of seven; and CD20, zero of 12. Three had stage IE and nine stage IV disease. Nine of 12 had an intermediate/high International Prognostic Index or high-risk disease. Computed tomography and positron emission tomography scan in four of 12 revealed extensive bone metastases. Eight of 12 are alive after treatment, with a median follow-up of 11+ months (range 1-24). Of the HIV-positive patients, five of six are alive with a median follow-up of 17 months. CONCLUSIONS: It appears that PBL are heterogenous in terms of clinical presentation and morphology. The outcome presented here is superior to that originally reported.

Systemic AL amyloidosis due to non-Hodgkin's lymphoma: an unusual clinicopathologic association.

Systemic AL amyloidosis (AL) is a disorder in which light chains form fibrillar deposits, leading to organ dysfunction and death. Rarely, AL has been associated with non-Hodgkin's lymphoma (NHL), although this association has not been well characterized. We report a series of six patients with AL associated with NHL, primarily lymphoplasmacytic lymphoma. Organ involvement was variable, with frequent bulky lymphadenopathy and visceral cavity deposits, but no cardiac involvement. Positron emission tomography scans were negative. Bone marrow and lymph node biopsies showed a mixed population of CD20+ lymphoid and CD138+ plasma cells. Serum free light chains were elevated, and correlated with response to therapy. Immunoglobulin light chain variable region (Ig VL) germline gene use was typical for AL, reflecting previously observed correlations between germline gene use and organ tropism. Five patients received rituximab-based therapies with two responses. Two patients underwent autologous stem cell transplantation with one complete haematological response. Four patients survive at 10-132 months from diagnosis. AL with NHL has distinctive clinical features but employs the same Ig VL gene repertoire as AL with clonal plasma cell dyscrasias. Serial serum free light chain levels are useful for tracking response to therapy. Treatments aimed at both lymphoid and plasma cell components appear warranted.

Analysis of mismatch repair defects in the familial occurrence of lymphoma and colorectal cancer.

Hereditary non-polyposis colon cancer (HNPCC) is an autosomal dominant disorder featuring familial clustering of colorectal and/or endometrial cancer, and other malignancies. Except for a rare case report, Hodgkin's disease (HD) and non-Hodgkin's lymphoma (NHL) have not been considered part of HNPCC. Recent murine models for HNPCC have shown an increased incidence of B- and T-cell lymphoma, as well as tumors of the gastrointestinal tract and other organ systems, involving defects in genes resulting in faulty mismatch repair (MMR) of DNA. These MMR genes include MLH1, MSH2, MSH3, MSH6, PMS1 and PMS2. We sought to analyze the occurrence of NHL and HD in families with clusters of colorectal cancers (CRC). Probands from 21 kindreds were classified as HNPCC (3), HNPCC-like (5), and HNPCC-variant (13); seen and followed by Clinical Genetics at Memorial Hospital the kindreds were assessed for the occurrence of NHL or HD. Of the 21 pedigrees, a total of 37 patients were identified who were diagnosed with leukemia, lymphoma, or HD. Fourteen of the 37 patients with a diagnosis of NHL or HD were further classified and showed varying histologies ranging from chronic lymphocytic leukemia/small lymphocytic lymphoma (2), mycosis fungoides (1), follicular lymphoma (1), extranodal marginal zone lymphoma of MALT type (2), diffuse large B-cell lymphoma (4), nodular sclerosis HD (3), and mixed cellularity HD (1). Microsatellite instability studies were performed on 6 cases but none showed evidence of replication error repair defects. Immunohistochemical stains performed on paraffin sections from these 6 representative cases showed differential protein expression of MLH1, MSH2, MSH6, and PMS2 when compared to normal reactive tissues from the same patient but showed no significant differences when compared to controls of non-familial, sporadic lymphomas. These results suggest that lymphomas arising in the setting of familial CRC do not bear the molecular hallmarks of HNPCC. Further studies are needed to explain the differential patterns of expression of RER-associated proteins in lymphomas, as well as the association of lymphomas and possibly renal cell cancers in a subset of kindreds in which CRC clustering is evident.

Deregulation of FCGR2B expression by 1q21 rearrangements in follicular lymphomas.

We report here the molecular cloning and characterization of a t(1;14)(q21;q32) in a follicular lymphoma (FL) with an unusual BCL2 aberration. Fluorescence in situ hybridization (FISH) and Southern blot analysis of tumor cells identified the translocation breakpoint within the 5' switch region of IGHG (Sgamma). We cloned the chimeric breakpoint region approximately 1.5 kbp downstream from the HindIII site of 5'Sgamma2 on chromosome 14q32 and identified a 360-bp novel segment with homology to the CpG island clone 11h8. Two BAC clones containing this sequence were isolated and mapped to 1q21 by FISH. BAC 342/P13 contained sequences homologous to Fcgamma receptors 2A, 3A, 2B, 3B, and a heat shock protein gene HSP70B. The translocation brought the Sgamma2 region of a productive IGH allele 20 approximately 30 kbp upstream of FCGR2B. As a result of the translocation, the b2 isoform of FCGR2B was overexpressed in the tumor. Screening of a panel of 76 B-cell lymphomas with 1q21-23 cytogenetic aberrations by Southern blot analysis using breakpoint probes identified an additional FL with a t(14;18)(q32;q21) and a breakpoint in the FCGR2B region. These results suggest that FCGR2B may be deregulated by 1q21 aberration in BCL2 rearranged FLs and possibly play a role in their progression.

Macrophage-derived chemokine expression in classical Hodgkin's lymphoma: application of tissue microarrays.

Hodgkin's disease (HD) is a lymphoid malignancy characterized by the presence of Reed-Sternberg (RS) and Hodgkin's cells in a background of mixed inflammatory cells and stromal reaction. Studies have documented that HD is a neoplasm associated with abnormal cytokine and chemokine production. To define the expression of macrophage-derived chemokine (MDC) in HD, 57 cases (18 lymphocyte predominant, 11 mixed cellularity, 28 nodular sclerosis) were stained for MDC by immunohistochemistry and compared with reactive lymph nodes as controls. MDC was expressed by RS cells in classical HD (CHD) and showed a distinct cytoplasmic and Golgi localization. Accumulating evidence suggests that lymphocyte-predominant HD (LPHD) represents an entity distinct from CHD, with different biological properties and clinical course. On the basis of the high level of MDC staining alone, CHD could be distinguished from LPHD (P <.001), which showed only faint staining of scattered histiocytes similar to control tissues. CHD cases with high MDC mRNA levels showed high levels of MDC protein expression by immunohistochemistry (P <.001) and significant eosinophil infiltration, suggesting that MDC may represent another molecule that plays a critical role in eosinophil recruitment. We also analyzed 102 cases of non-Hodgkin's lymphoma and normal spleen, lymph node, and thymic tissue. High levels of MDC expression were specific to CHD cases because only low levels of MDC were observed in a minor subset of LPHD, NHL or normal lymphoid tissues.

Chemokine gene expression and clonal analysis of B cells in tissues involved by lymphoid interstitial pneumonitis from HIV-infected pediatric patients.

Lymphoid interstitial pneumonitis (LIP), a frequent pulmonary complication in HIV-infected pediatric patients, is characterized histologically by marked infiltration of lymphoid cells. We sought to evaluate the nature and pathogenesis of the lymphoid infiltrates and to examine the relationship of LIP to pulmonary MALT lymphoma that has been described in pediatric HIV positive patients. To examine the potential contribution of chemokines and cytokines to the inflammatory cell recruitment in tissues involved by lymphoid interstitial pneumonitis from HIV-infected pediatric patients, RNA was extracted from paraffin-embedded tissues from five lung biopsies in four pediatric HIV-positive patients and from five control, normal lung biopsies in five HIV-negative patients and was analyzed by semiquantitative RT-PCR for the expression of cytokines (TNF-alpha, GM-CSF, IFN-gamma, IL-4, IL-6, IL-10, and IL-18) and chemokines (IP-10, Mig, regulated upon activation, normal T expressed and secreted [RANTES], and MIP1-alpha and beta) after normalization for G3PDH. Expression of IL-18 was increased, as well as expression of IFN-gamma-inducible chemokines IP-10 and Mig in LIP tissues compared with controls. RANTES and MIP1-alpha and -beta were also increased in pediatric LIP lesions compared with controls. In contrast, expression of TNF-alpha, GM-CSF, IL-10, and IL-6 was variable in LIP tissues and controls. In addition, clonality of the B-cell population was evaluated by VDJ-PCR. A polyclonal B-cell population was shown in all five biopsies from five patients with LIP; and in one patient with concurrent LIP and MALT lymphoma, a band of increased intensity was observed in the LIP biopsy that was identical in size to the monoclonal band in the concurrent MALT lymphoma biopsy. These results provide evidence of high-level expression of certain chemokines in lymphoid interstitial pneumonitis tissues and suggest that chemokines and cytokines may play an important role in the recruitment of inflammatory cell infiltrates into these tissues. In addition, LIP may represent an early stage of MALT lymphoma or an immunologic response to a chronic antigenic stimulus that may provide a milieu or microenvironment for the evolution of a monoclonal B-cell population.

Increases in circulating and lymphoid tissue interleukin-10 in autoimmune lymphoproliferative syndrome are associated with disease expression.

Autoimmune lymphoproliferative syndrome (ALPS) is an inherited disorder in which genetic defects in proteins that mediate lymphocyte apoptosis, most often Fas, are associated with enlargement of lymph nodes and the spleen and a variety of autoimmune manifestations. Some patients with ALPS have relatives with these same apoptotic defects, however, who are clinically well. This study showed that the circulating levels of interleukin 10 (IL-10) were significantly higher (P <.001) in 21 patients with ALPS than in healthy controls. Moreover, the peripheral blood mononuclear cells (PBMCs) and lymphoid tissues of these patients with ALPS contained significantly higher levels of IL-10 messenger RNA (mRNA; P <.001 and P <.01, respectively). By fractionating PBMC populations, disproportionately high concentrations of IL-10 mRNA were found in the CD4(-)CD8(-) T-cell population, expansion of which is virtually pathognomonic for ALPS. Immunohistochemical staining showed intense IL-10 protein signals in lymph node regions known to contain CD4(-)CD8(-) T cells. Nonetheless, in vitro studies showed no influence of IL-10 on the survival of CD4(-)CD8(-) T cells. Overexpression of IL-10 in patients with inherited apoptotic defects is strongly associated with the overt manifestations of ALPS.

Peripheral T-cell lymphoma with aberrant expression of CD79a and CD20: a diagnostic pitfall.

Immunohistochemical studies are increasingly used for the routine diagnosis of lymphomas as it is widely accepted that lymphomas of different cell lineages vary in their prognosis and response to therapy. A case of peripheral T-cell lymphoma with aberrant expression of B-cell-associated antigens L-26 (CD20) and mb-1 (CD 79a) is described. The disease pursued an aggressive clinical course, and the patient died of disease 6 weeks after presentation. Immunohistochemical studies demonstrated expression of both T- and B-cell-associated antigens, including CD3, CD8, CD43, TIA-1, CD20, and CD79a. Other markers expressed by the tumor cells included CD56 and S-100. Of interest, betaF-1 staining for the beta chain of T-cell receptor (TCR) complex was positive in the small admixed T lymphocytes but was negative in the tumor cells, raising the possibility of a gamma/delta T-cell lymphoma. Molecular studies by polymerase chain reaction (PCR) demonstrated clonal TCR-gamma chain gene rearrangement without evidence for a clonal rearrangement of the immunoglobulin heavy chain gene. PCR for HHV-8 related sequences was negative. Mb-1 is an IgM-associated protein that was thought to be restricted to normal and neoplastic B cells. Although its coexpression has been reported in up to 10% cases of precursor T-cell lymphoblastic lymphoma, the coexpression of both CD20 and CD79a has not been described in mature T-cell malignancies. Biphenotypic lymphomas associated with HHV-8 have been reported in immunodeficiency, but no evidence of immune deficiency was identified, and studies for EBV and HHV-8 were negative. This case illustrates that no marker has absolute lineage specificity and that immunophenotypic studies should always be performed with panels of monoclonal antibodies. Moreover, cases with ambiguous phenotypes may require genotypic studies for precise lineage assignment.

Recurring chromosomal abnormalities in non-Hodgkin's lymphoma: biologic and clinical significance.

Non-Hodgkin's lymphomas (NHLs) are a group of clinically important neoplasms with a complex biology that makes their classification and treatment difficult. Their incidence is increasing and they cause significant morbidity and mortality. NHLs result from transformation of B and T/natural killer (NK) cells. Their genetic hallmark is chromosomal translocations resulting from aberrant rearrangements of IG and TCR genes, which lead to inappropriate expression of genes at reciprocal breakpoints that regulate a variety of cellular functions, including gene transcription, cell cycle, apoptosis, and tumor progression. Cytogenetics followed by molecular genetic analysis of some of the recurring translocations continues to provide new insights into lymphomagenesis and cell biology. More recently, chromosomal and gene amplification and gene deletion have been recognized as frequent genetic changes that may play a role in lymphoma progression and clinical behavior. In this review, cytogenetic data pertaining to recurring chromosomal changes on lymphomas are reviewed and examined in relation to their relevance to lymphoma development, classification, and clinical behavior.

Fulminant EBV(+) T-cell lymphoproliferative disorder following acute/chronic EBV infection: a distinct clinicopathologic syndrome.

This study describes the clinicopathologic features of 5 patients who developed a fulminant Epstein-Barr virus (EBV)-positive clonal T-cell lymphoproliferative disorder (LPD) after acute EBV infection. One additional patient developed a similar disorder in the setting of long-standing chronic active EBV infection. Detailed immunophenotyping, in situ hybridization for EBV early RNA-1 (EBER1) and polymerase chain reaction (PCR) analyses for immunoglobulin (Ig) heavy chain and T-cell receptor (TCR)-gamma gene rearrangements were performed on paraffin-embedded tissue from all patients. In addition, EBV strain typing and detection of the characteristic 30-bp deletion of the latent membrane protein-1 (LMP-1) gene were performed by PCR. Controls included 8 cases of uncomplicated infectious mononucleosis (IM). Patients included 4 males and 2 females with a median age of 18 years (2-37 years). Three patients were Mexican, 2 were white, and 1 was of Asian descent. All presented with fever, hepatosplenomegaly, and pancytopenia; 5 were previously healthy, but had a clinical history of a recent viral-like upper respiratory illness (1 week to 2 months), and 1 patient had documented chronic active EBV infection for 7 years. Serologic data for EBV were incomplete but titers were either negative or only modestly elevated in 3 cases. In 1 case serology was consistent with severe chronic active EBV infection. In the remaining 2 cases serologic studies were not performed. All patients died within 7 days to 8 months of presentation with T-cell LPD. On histologic examination, the liver and spleen showed prominent sinusoidal and portal lymphoid infiltrates of CD3(+), beta F1(+), EBER1(+) T cells lacking significant cytologic atypia. Two cases were CD4(+), 2 cases were CD8(+), and 2 cases had admixed CD4(+) and CD8(+) cells without clear subset predominance. All were TIA-1(+), CD56(-). Only rare B cells were noted. Marked erythrophagocytosis was present. Molecular analysis revealed identical T-cell clones in 2 or more sites (liver, spleen, lymph node) in 5 cases. All patients carried type A EBV; 4 cases had wild-type EBV-LMP, and 2 showed the 30-bp deletion. This fulminant T-cell LPD after acute/chronic EBV infection is characterized by hepatosplenomegaly, often without significant lymphadenopathy, fever, liver failure, pancytopenia, and erythrophagocytosis indicative of a hemophagocytic syndrome. EBV serology may be misleading, with lack of elevated titers. The presence of an EBER1(+) T-cell infiltrate with scant B cells should alert one to this diagnosis. Although cytologic atypia is minimal, studies for T-cell clonality confirm the diagnosis. (Blood. 2000;96:443-451)

The role of chemokines in Hodgkin's disease.

Recent studies have analyzed the expression of chemokines in tissues involved by Hodgkin's disease (HD) (1). The data indicate a significant role for chemokine expression in the pathobiology and pathophysiology of HD. In general, HD tissues showed higher levels of chemokine expression than reactive lymphoid hyperplasia (RLH) tissues. There were major differences in chemokine expression among the different HD subtypes. Similar to previous studies in athymic mice that identified a pattern of chemokine response induced by Epstein-Barr virus (EBV)-infected cells, the expression of IP-10, Mig, RANTES, and MIP1-alpha was higher in EBV positive compared to EBV negative HD tissues. In addition, there was a direct correlation of eotaxin expression with tissue eosinophilia. By immunohistochemistry, IP-10 and Mig proteins localized in the malignant Reed-Steinberg (RS) cells and their variants, and to some surrounding inflammatory cells. Eotaxin localized to fibroblasts and smooth muscle of blood vessels. In this review, we discuss the patterns of expression of IP-10, Mig, RANTES, MIP1-alpha, and eotaxin in HD and its subtypes, and the relationship to EBV positivity, LMP1 expression, tissue eosinophilia and T cell infiltration. In addition, we discuss the potential role of chemokines and cytokines in the pathobiology of HD.