Involved-nodal radiation therapy as a component of combination therapy for limited-stage Hodgkin's lymphoma: a question of field size

PURPOSE

Combined-modality therapy is the standard of care for limited-stage Hodgkin's lymphoma (HL). Radiation therapy has evolved from extended-field radiation therapy (EFRT) to involved-field radiation therapy (IFRT), reducing toxicity while maintaining high cure rates. Recent publications recommend a further reduction to involved-nodal radiation therapy (INRT), however, this has not been clinically validated.

PATIENTS AND METHODS

We identified 325 patients with limited-stage HL, diagnosed between May 1, 1989 and April 1, 2005, and treated with chemotherapy and radiation therapy following era-specific guidelines: EFRT until 1996; IFRT from 1996 to 2001; INRT < or = 5 cm from 2001 to the present. INRT < or = 5 cm was defined as the prechemotherapy nodal volume with margins < or = 5 cm to account for physiological movement, set-up variation, and the limitations of conventional simulation and radiation therapy techniques. Exclusion criteria were age younger than 16, fluorine-18 fluorodeoxyglucose positron emission tomography, non-doxorubicin, bleomycin, vinblastine, and dacarbazine-like chemotherapy, and/or more than four chemotherapy cycles.

RESULTS

At diagnosis, median age was 35 years; 52% male; stage IA 29%; stage IIA 71%. Ninety-five percent of patients received two chemotherapy cycles. The three radiation therapy groups were: EFRT, 39%; IFRT, 30%; and INRT < or = 5 cm, 31%. Median follow-up of living patients was 80 months. Median time to relapse was 37 months. Twelve relapses occurred: four after EFRT (3%); five after IFRT (5%); and three after INRT < or = 5 cm (3%; P = .9). No marginal recurrences occurred after INRT < or = 5 cm. Locoregional relapse (LRR) occurred in five patients: three after EFRT; two with IFRT; and none with INRT < or = 5 cm. At 5 years, progression-free survival (PFS) was 97%, and overall survival (OS) was 95%. At 10 years, PFS and OS were 95% and 90%, respectively.

CONCLUSION

Reduction in field size appears to be safe, without an increased risk of LRR in patients receiving INRT < or = 5 cm.

Prognosis and primary therapy in peripheral T-cell lymphomas

Peripheral NK/T-cell neoplasms are an uncommon group of diseases that show distinct racial and geographic variation. The prognostic significance of the T-cell phenotype has been clearly defined in recent studies by using modern lymphoma classification systems. However, within this heterogenous group of neoplasms, some have a more favorable prognosis, such as ALK-positive anaplastic large-cell leukemia (ALCL) and primary cutaneous ALCL, and some have ultimately fatal courses with standard chemotherapy programs (e.g., hepatosplenic gammadelta T-cell lymphomas). Further, unlike the benefits observed with CHOP chemotherapy in the treatment of diffuse large B-cell lymphoma (DLBCL), peripheral T-cell lymphomas (PTCL), other than ALK-positive ALCL, are relatively chemoresistant to this regimen. Given disease rarity and biological heterogeneity, advances in diagnosis, prognosis and treatment have lagged behind DLBCL. Recently, however, studies are emerging that focus specifically on PTCLs with the ultimate goal of better understanding disease biology and developing more effective therapies.

Frequent occurrence of deletions in primary mediastinal B-cell lymphoma

Primary mediastinal B-cell lymphoma (PMBCL) is a distinct subtype of diffuse large B-cell lymphoma. PMBCL has been previously studied with a variety of genomic techniques resulting in frequent detection of chromosomal gains; however, chromosomal losses have been rarely reported. This finding contrasts many other types of lymphoma, in which deletions are common. We hypothesize that segmental losses do exist but may have escaped detection by methods used in the previous studies. Using array comparative genomic hybridization to a tiling-resolution microarray encompassing the entire human genome, PMBCL samples were analyzed for genomic copy number alterations. An almost equal number of gains and losses of chromosomal material were detected throughout the genome (216 vs. 193, respectively). A selection of these DNA copy number alterations were confirmed by quantitative real-time PCR. Recurrent gains were detected at all previously reported regions of gain, including 9p seen in approximately 70% of cases. Recurrent chromosomal losses were observed at 1p, 3p, 4q, 6q, 7p, and 17p, with a novel event at 1p13.1-p13.2 representing the most frequent at 42% of cases analyzed. We conclude that consistent losses are present in the PMBCL genome. Given the similar frequency of losses to that of segmental gains of DNA, they are likely to play an important role in the pathogenesis of PMBCL.

A phase II study of ispinesib (SB-715992) in patients with metastatic or recurrent malignant melanoma: a National Cancer Institute of Canada Clinical Trials Group trial

To assess the response rate and toxicity of the kinesin spindle protein (KSP) inhibitor, ispinesib, in malignant melanoma. Seventeen patients were enrolled from April to November 2005. Ispinesib was administered as a 1-hour infusion at a dose of 18 mg/m2 once every 3 weeks until disease progression. No objective responses were seen. Six patients (35%) had a best response of stable disease for a median duration of 2.8 months. Disease progression was documented in 9 (53%) after 1 or 2 cycles. Eighty-eight percent of patients received > or =90% of planned dose intensity. Grade 3 non-hematologic toxicities included dizziness (1) and blurred vision (1). There was one episode of febrile neutropenia, but no grade 3 or 4 biochemical adverse events. Pharmacokinetics was consistent with prior studies. KSP immunoreactivity was seen in 14 of 16 available archival tissue samples (88%). Ispinesib can be safely administered using the dose and schedule employed, with mild hematologic and non-hematologic toxicity. No objective responses were observed, and further development of single-agent ispinesib in malignant melanoma is not recommended. Although KSP expression appears to be common in melanoma, KSP may not be a suitable target for its treatment.

Peripheral T-cell Lymphomas

Peripheral T-cell lymphomas (PTCLs) are a biologically diverse and uncommon group of diseases. Compared to their B-cell counterparts, PTCLs remain largely unexplored and the optimal treatment ill-defined due to disease rarity and biological heterogeneity. With the notable exception of ALK-pos anaplastic large cell lymphoma (ALCL), the prognosis of most PTCL subtypes is extremely is poor with a 5 y overall survival of approximately 15-30% in most series. The international prognostic index has been useful in defining different risk groups within some PTCL subtypes, including PTCL unspecified (PTCLU). Attempts have been made to define disease subgroups within the biologically heterogeneous PTCLU based on T-helper chemokine receptor profile and/or gene expression profiling which may aid in tailoring new therapies. Future clinical trials are needed that focus specifically on PTCL to advance our understanding and define the optimal management in this disease.

Phase II study of enzastaurin, a protein kinase C beta inhibitor, in patients with relapsed or refractory diffuse large B-cell lymphoma

PURPOSE

Protein kinase C beta (PKCbeta) was identified by gene-expression profiling, preclinical evaluation, and independent immunohistochemical analysis as a rational therapeutic target in diffuse large B-cell lymphoma (DLBCL). We conducted a multicenter phase II study of a potent inhibitor of PKCbeta, enzastaurin, in patients with relapsed or refractory DLBCL.

PATIENTS AND METHODS

Enzastaurin was taken orally once daily until disease progression or unacceptable toxicity occurred. Study end points included freedom from progression (FFP) for > or= two cycles (one cycle = 28 days), objective response, and toxicity.

RESULTS

Fifty-five patients (median age, 68 years) were enrolled. Patients had received a median number of two prior therapies (range, one to five); six patients relapsed after high-dose therapy and autologous stem-cell transplantation. Only one grade 4 toxicity (hypomagnesemia) occurred. Grade 3 toxicities included fatigue (n = 2), edema (n = 1), headache (n = 1), motor neuropathy (n = 1), and thrombocytopenia (n = 1). No grade 3 or 4 neutropenia occurred. No deaths or discontinuations due to toxicity were reported. Fifteen patients completed less than one cycle of therapy. Twelve of 55 patients (22%; 95% CI, 13% to 46%) experienced FFP for two cycles, and eight patients remained free from progression for four cycles (15%; 95% CI, 6% to 27%). Four patients (7%; 95% CI, 2% to 18%), including three complete responders and one patient with stable disease, continue to experience FFP 20+ to 50+ months after study entry.

CONCLUSION

Treatment with enzastaurin was well-tolerated and associated with prolonged FFP in a small subset of patients with relapsed or refractory DLBCL. Further studies of enzastaurin in DLBCL are warranted.

Expression of TRAF1 and Nuclear c-Rel Distinguishes Primary Mediastinal Large Cell Lymphoma From Other Types of Diffuse Large B-cell Lymphoma

Primary mediastinal large B-cell lymphoma (PMLBCL) is a recently identified subtype of diffuse large B-cell lymphoma (DLBCL) that is difficult to distinguish from other types of DLBCL on the basis of histologic features alone. We recently identified a molecular signature of PMLBCL that is distinct from other forms of DLBCL but shares features with classical Hodgkin lymphoma. This signature includes activation of the nuclear factor kappaB (NFkappaB) signaling pathway, which in part, acts through nuclear translocation of c-Rel containing NFkappaB transcriptional complexes, and subsequent expression of NFkappaB target genes such as tumor necrosis factor receptor-associated factor-1 (TRAF1). Using standard immunohistochemical techniques, we examined 251 large B-cell lymphomas (78 cases of PMLBCL and 173 cases of other types of DLBCL) to determine whether the expression patterns of c-Rel and TRAF1 could reliably distinguish between PMLBCL and other types of DLBCL. Robust nuclear c-Rel was present in 31 of 48 (65%) cases of PMLBCL and 28 of 160 (18%) cases of DLBCL. In addition, cytoplasmic TRAF1 expression was seen in 48 of 78 (62%) cases of PMLBCL, but only 20 of 173 (12%) cases of DLBCL. Finally, the combined expression of nuclear c-Rel and TRAF1 was seen in 24 of 45 cases (53%) of PMLBCL, but in only 3 of 156 cases (2%) of other types of DLBCL. Thus, the combined nuclear localization of c-Rel and the cellular expression of TRAF1 is a highly specific (specificity=98%) means to distinguish PMLBCL from DLBCL that is readily applicable to routine surgical pathology practice.

Fatal postlymphoma chemotherapy hepatitis B reactivation secondary to the emergence of a YMDD mutant strain with lamivudine resistance in a noncirrhotic patient

Hepatitis B reactivation is a well-known complication during or after chemotherapy in chronic hepatitis B (HBV) carriers. The current practice guidelines in Canada and the United States recommends patients receive antiviral prophylaxis prior to the onset of chemotherapy in chronic HBV carriers with lamivudine. We report a case of a 57-year-old man with follicular lymphoma on lamivudine prophylaxis and no clinical evidence of cirrhosis, and developed fatal HBV reactivation after the emergence of a YMDD mutant strain of HBV that confers lamivudine resistance. Fatal reactivation secondary to the development of lamivudine resistance has not, to date, been well- reported. Our experience indicates the need to carefully monitor patients for suspected drug- resistant HBV mutants with the addition of anti-viral agents effective against the YMDD mutational strain, when lamivudine resistance emerges.

The revised International Prognostic Index (R-IPI) is a better predictor of outcome than the standard IPI for patients with diffuse large B-cell lymphoma treated with R-CHOP

Diffuse large B-cell lymphoma (DLBCL) is a heterogeneous entity, with patients exhibiting a wide range of outcomes. The addition of rituximab to CHOP chemotherapy (R-CHOP)has led to a marked improvement in survival and has called into question the significance of previously recognized prognostic markers. Since randomized controlled trials of R-CHOP in DLBCL have included select subgroups of patients, the utility of the International Prognostic Index (IPI) has not been reassessed. We performed a retrospective analysis of patients with DLBCL treated with R-CHOP in the province of British Columbia to assess the value of the IPI in the era of immunochemotherapy. The IPI remains predictive, but it identifies only 2 risk groups. Redistribution of the IPI factors into a revised IPI (R-IPI) provides a more clinically useful prediction of outcome. The R-IPI identifies 3 distinct prognostic groups with a very good (4-year progression-free survival [PFS] 94%, overall survival [OS] 94%), good (4-year PFS 80%, OS 79%), and poor (4-year PFS 53%, OS 55%) outcome, respectively (P < .001). The IPI (or R-IPI) no longer identifies a risk group with less than a 50% chance of survival. In the era of R-CHOP treatment, the R-IPI is a clinically useful prognostic index that may help guide treatment planning and interpretation of clinical trials.

Primary Mediastinal Large B‐Cell Lymphoma

Primary mediastinal large B-cell lymphoma represents a distinct entity with unique clinicopathologic features and a molecular gene-expression signature reminiscent of nodular sclerosis subtype of classical Hodgkin's lymphoma. Recent studies, including those using a refined molecular signature, suggest that the outcome is more favorable than that of diffuse large B-cell lymphoma. Using historical comparisons, dose-dense and dose-intensive regimens may be more effective than cyclophosphamide, doxorubicin, vincristine, and prednisone chemotherapy; however, the impact of adding rituximab to these regimens and effect on outcome comparisons is unknown. Clinical trials exploring these questions in addition to the benefit of consolidative radiotherapy are necessary to definitively answer these questions.

Primary paranasal sinus lymphoma: natural history and improved outcome with central nervous system chemoprophylaxis

Non-Hodgkin's lymphoma of the paranasal sinus is an uncommon presentation of extranodal lymphoma. Its natural history, treatment and prognosis have been infrequently characterized in the medical literature; however, a tendency to involve the central nervous system (CNS) has been noted. In British Columbia (population 4 million), a central database for lymphomas has allowed us to accurately track cases of paranasal sinus lymphoma diagnosed since 1980. A retrospective review was performed on the 44 patients who presented with primary paranasal sinus lymphoma (stage I or II) between 1980 and 1999. Histologic features were identified and immunophenotypic classification performed. Complete diagnostic and follow-up data including stage, treatment, response rates, sites of relapse and survival data were available for all patients. There were 26 men and 18 women. The types of lymphoma found were: diffuse large B cell (including immunoblastic), n = 37 (84%); T/NK nasal type, n = 3 (8%); peripheral T cell, not otherwise classified, n = 2 (4%); and others, n = 2 (4%). The median age at presentation was 66 years (range 27-97 years). The median follow-up for living patients was 114 months. For all 44 patients, the 5- and 10-year overall survivals were 48% and 41% and the disease-specific survivals 62% and 62%, respectively. Beginning in May 1985, intrathecal chemotherapy was added to our standard treatment plan of multi-agent chemotherapy and local irradiation. Before 1985, 2 of 5 patients developed leptomeningeal metastasis. Following the institution of intrathecal chemotherapy, only 8% (3 of 39) of patients have developed CNS disease. Introduction of intrathecal chemoprophylaxis was also associated with an improvement in overall survival from 20% to 51% and disease-specific survival from 40% to 65%. Primary paranasal sinus lymphoma is an uncommon presentation of lymphoma that carries the potential risk of spreading to the leptomeninges. Treatment with combined modality chemotherapy and irradiation can cure many patients and the addition of intrathecal chemotherapy may reduce the risk of CNS relapse.

Favorable outcome of primary mediastinal large B-cell lymphoma in a single institution: the British Columbia experience

BACKGROUND

Primary mediastinal large B-cell lymphoma (PMBCL) is a distinct clinico-pathological subtype of diffuse large B-cell lymphoma (DLBCL). The optimal treatment is unknown, with some studies suggesting a superior outcome with dose-intensive chemotherapy regimens, and the role of radiotherapy remains ill-defined.

PATIENTS AND METHODS

The British Columbia Cancer Agency lymphoma database was searched and records reviewed to identify those patients presenting with a prominent mediastinal mass and considered to be PMBCL based on the current REAL/WHO classifications. Patients were treated based on era-specific BCCA guidelines (1980-1992 MACOPB/VACOPB; 1992-2001 CHOP-type; 2001-present CHOP-R). Beginning in January 1998 involved-field radiotherapy was recommended to be routinely administered following chemotherapy. Prior to this, use of radiotherapy was individualized in advanced disease.

RESULTS

In total, 153 patients with newly diagnosed PMBCL were identified between 28 July 1980 and 30 June 2003. The median age was 37 years (range 13-82) and the majority had stage I/II (74%), bulky mediastinal disease (75%). Overall (OS) and progression-free (PFS) survival at 5 years for the entire cohort were 75% and 69%, respectively. In direct comparison with a cohort of patients with DLBCL (n = 1273), OS (P = 10(-4)) and PFS (P = 0.0001) favored PMBCL. The age-adjusted International Prognostic Index (aaIPI) was not predictive of survival (P = 0.18). Five-year OS in patients < 65 years old treated with MACOPB/VACOPB, CHOP-R and CHOP-type was 87%, 81% and 71% respectively (P = 0.048). In pair-wise survival comparisons, only MACOPB/VACOPB and CHOP-type treated patients were significantly different (P = 0.016). In Cox multiple regression analysis, poor performance status remained the only predictor of survival, with treatment received demonstrating a trend to worse outcome for patients treated with CHOP-type regimens (P = 0.09). In an intention-to-treat analysis comparing the era before radiotherapy was routinely administered with after, there was no significant difference in 5-year PFS (74% versus 62%; P = 0.09) or OS (78% versus 69%; P = 0.14).

CONCLUSIONS

In this single institution, population-based retrospective study, we found that PMBCL patients have excellent survival rates and a distinct plateau is observed in PFS, in striking comparison to DLBCL. The aaIPI was not predictive of survival in this population, suggesting that other prognostic models may be better suited for risk stratification. Dose-intensified chemotherapy with MACOPB or VACOPB demonstrated a trend to superior outcome over CHOP-type chemotherapy. However, further randomized studies are needed and the impact of rituximab on these comparisons must be considered. Finally, the routine addition of radiotherapy does not improve survival.

NFkappaB activity, function, and target-gene signatures in primary mediastinal large B-cell lymphoma and diffuse large B-cell lymphoma subtypes

Primary mediastinal large B-cell lymphoma (MLBCL) shares important clinical and molecular features with classic Hodgkin lymphoma, including nuclear localization of the nuclear factor kappaB (NFkappaB) subunit c-REL (reticuloendotheliosis viral oncogene homolog) in a pilot series. Herein, we analyzed c-REL subcellular localization in additional primary MLBCLs and characterized NFkappaB activity and function in a MLBCL cell line. The new primary MLBCLs had prominent c-REL nuclear staining, and the MLBCL cell line exhibited high levels of NFkappaB binding activity. MLBCL cells expressing a superrepressor form of inhibitor of kappa B alpha signaling (IkappaB alpha) had a markedly higher rate of apoptosis, implicating constitutive NFkappaB activity in MLBCL cell survival. The transcriptional profiles of newly diagnosed primary MLBCLs and diffuse large B-cell lymphomas (DLBCLs) were then used to characterize the NFkappaB target gene signatures of MLBCL and specific DLBCL subtypes. MLBCLs expressed increased levels of NFkappaB targets that promote cell survival and favor antiapoptotic tumor necrosis factor alpha (TNFalpha) signaling. In contrast, activated B cell (ABC)-like DLBCLs had a more restricted, potentially developmentally regulated, NFkappaB target gene signature. Of interest, the newly characterized host response DLBCL subtype had a robust NFkappaB target gene signature that partially overlapped that of primary MLBCL. In this large series of primary MLBCLs and DLBCLs, NFkappaB activation was not associated with amplification of the cREL locus, suggesting alternative pathogenetic mechanisms.

TRAF1 Expression and c-Rel Activation Are Useful Adjuncts in Distinguishing Classical Hodgkin Lymphoma From a Subset of Morphologically or Immunophenotypically Similar Lymphomas

We demonstrate that the expression of TRAF1 and activated c-Rel, two proteins that function in signaling events downstream of activated CD30 in Reed-Sternberg cells, reliably distinguish classical Hodgkin lymphoma from anaplastic large cell lymphoma, nodular lymphocyte predominant Hodgkin lymphoma, and nonmediastinal diffuse large B-cell lymphoma. By immunohistochemistry, we found strong TRAF1 staining in 21 of 25 cases of classical Hodgkin lymphoma. In contrast, strong TRAF1 staining was present in only 1 of 17 cases of anaplastic large cell lymphoma, 0 of 15 cases of lymphocyte predominant Hodgkin lymphoma, and 2 of 36 cases of nonmediastinal diffuse large B-cell lymphoma. Nuclear staining for c-Rel, a pattern consistent with NFkappaB activation, was observed in the Reed-Sternberg cells in 23 of 25 cases of classical Hodgkin lymphoma but only in 1 of 15 cases of anaplastic large cell lymphoma and 3 of 15 cases of nodular lymphocyte predominant Hodgkin lymphoma. A heterogeneous pattern of subcellular c-Rel localization was found in nonmediastinal diffuse large B-cell lymphoma. Taken together, the combination of strong cytoplasmic TRAF1 expression and nuclear c-Rel was present in 80% of cases of classical Hodgkin lymphoma (n = 25) but in only 3% of cases of the other malignant lymphomas tested (n = 62). Thus, the differential expression patterns of downstream components in the CD30 signaling pathway may prove a useful adjunct in distinguishing cases of classical Hodgkin lymphoma from other malignant lymphomas in routine clinical practice.

Characterization of peripheral T-cell lymphomas in a single North American institution by the WHO classification

BACKGROUND

All peripheral T-cell lymphomas (PTCLs) diagnosed at a single institution were evaluated to determine the unique clinical features and outcome of specific entities and test the predictive validity of the International Prognostic Index (IPI).

PATIENTS AND METHODS

Cases of PTCL seen at the British Columbia Cancer Agency between 1981 and 2000 were identified. Pathologic material was re-assessed and classified according to the WHO classification, and patients were staged and treated uniformly according to era-specific guidelines. In total, there were 199 patients with PTCL and the most common subtypes were peripheral T-cell lymphoma unspecified (PTCL-US) (59%), anaplastic large-cell lymphoma, systemic type (ALCL) (17%) and extranodal NK/T-cell lymphoma, nasal and nasal-type (NASAL) (9%). Most patients were treated with CHOP-type chemotherapy.

RESULTS

Three distinct prognostic subgroups were notable on survival analysis: favorable (cutaneous ALCL), 5-year overall survival (OS) 78%; intermediate [PTCL, ALCL and angioimmunoblastic lymphoma (AILT)], 5-year OS 35-43%; unfavorable [NASAL and enteropathy-type T-cell lymphoma (ETTL)], 5-year OS 22-24%. Furthermore, in PTCL-US and ALCL clinical separation of patients into good risk (IPI 0,1) and poor risk (IPI > or =2) subsets was demonstrated.

CONCLUSIONS

A large proportion of PTCL patients have poor risk disease and/or a histologically aggressive subtype with frequent relapse and unfavorable outcome. For these patients, treatment with CHOP chemotherapy is only minimally effective and new strategies need to be developed, an effort that will require a multi-institution international collaboration due to the rarity of most subtypes.

Aggressive Peripheral T-Cell Lymphomas (Specified and Unspecified Types)

Peripheral T-cell lymphomas (PTCLs) are a biologically diverse and uncommon group of diseases. Compared to their B-cell counterparts, PTCLs remain largely unexplored and the optimal treatment ill-defined due to disease rarity and biological heterogeneity. For the majority of PTCL subtypes, prognosis is poor with a 5-year overall survival of approximately 30% in most series.

The notable exception is ALK-positive anaplastic large-cell lymphoma (ALK-pos ALCL), which has a superior outcome. The international prognostic index can be used to some extent to define risk groups within some PTCL subtypes, including PTCL unspecified (PTCLUS). It is likely that the observed clinical heterogeneity reflects differences at the molecular level. With the more widespread availability of gene expression profiling, it may be possible in the future to further refine the classification of PTCLs and elucidate novel therapeutic targets. Future clinical trials are needed that focus specifically on PTCL to advance our understanding and define the optimal management in this disease.

Molecular Signatures of Lymphoma

Hematologic malignancies have historically been characterized by morphologic, immunophenotypic, molecular, and genetic features. However, morphologically identical tumors can have clearly distinct clinical outcomes, suggesting underlying biological heterogeneity. Recent advances in microarray technology have helped the classification of lymphoid malignancies evolve to a new refined level. In addition to the discovery of new disease subclasses defined by unique molecular profiles, gene expression patterns can be correlated with specific genetic abnormalities and prognoses. Furthermore, the discovery of new disease subtypes has provided further insight into lymphoma biology and pathogenesis. Unique gene signatures can highlight key deregulated pathways that are active in molecular disease categories, and in some cases these findings have elucidated new targets for novel therapeutic approaches. This review summarizes the current status of molecular profiling in non-Hodgkin lymphomas. In this review, we have endeavored to include data from multiple investigator groups and tried to cover the breadth of lymphoid tumors, excluding acute and chronic leukemias.

Molecular profiling of diffuse large B-cell lymphoma identifies robust subtypes including one characterized by host inflammatory response

Diffuse large B-cell lymphoma (DLBCL) is a heterogeneous disease with recognized variability in clinical outcome, genetic features, and cells of origin. To date, transcriptional profiling has been used to highlight similarities between DLBCL tumor cells and normal B-cell subtypes and associate genes and pathways with unfavorable outcome. To identify robust and highly reproducible DL-BCL subtypes with comprehensive transcriptional signatures, we used a large series of newly diagnosed DLBCLs, whole genome arrays, and multiple clustering methods. Tumors were also analyzed for known common genetic abnormalities in DLBCL. There were 3 discrete subsets of DLBCL-"oxidative phosphorylation," "B-cell receptor/proliferation," and "host response" (HR)-identified characterized using gene set enrichment analysis and confirmed in an independent series. HR tumors had increased expression of T/natural killer cell receptor and activation pathway components, complement cascade members, macrophage/dendritic cell markers, and inflammatory mediators. HR DLB-CLs also contained significantly higher numbers of morphologically distinct CD2+/CD3+ tumor-infiltrating lymphocytes and interdigitating S100+/gamma interferon-induced lysosomal transferase-positive (GILT+) CD1a-/CD123- dendritic cells. The HR cluster shared features of histologically defined T-cell/histiocyte-rich B-cell lymphoma, including fewer genetic abnormalities, younger age at presentation, and frequent splenic and bone marrow involvement. These studies identify tumor microenvironment and host inflammatory response as defining features in DLBCL and suggest rational treatment targets in specific DLBCL subsets.

The phosphodiesterase PDE4B limits cAMP-associated PI3K/AKT-dependent apoptosis in diffuse large B-cell lymphoma

Diffuse large B-cell lymphoma (DLBCL) is a common and often fatal malignancy. Advances in the treatment of this disease will require the identification of novel therapeutic targets. We previously defined an expression signature of outcome in DLBCL and found that the phosphodiesterase PDE4B was overexpressed in fatal/refractory tumors. Phosphodiesterase 4B (PDE4B) inactivates the second messenger cyclic adenosine 3',5' monophosphate (cAMP) and abrogates its inhibitory effects in B lymphocytes. Hence, DLBCLs that express high PDE4B levels may be resistant to cAMP-induced apoptosis, contributing to their less favorable outcome. Herein, we confirmed the risk-related expression of PDE4B in an independent series of primary DLBCLs and defined the enzyme's role in modulating cAMP-induced apoptosis in parental DLBCL cell lines or those reconstituted with wild-type or mutant PDE4B. The cAMP-mediated apoptosis of DLBCLs was largely independent of the previously described cAMP effectors, protein kinase A (PKA) and exchange protein directly activated by cAMP (EPAC), but associated with inhibition of the phosphatidylinositol 3-kinase (PI3K)/AKT pathway. The central role of AKT in this process was confirmed by expressing constitutively active mutants of this kinase in DLBCL cells. Our findings highlight the important role of cAMP signaling in DLBCL and suggest that clinically relevant PDE4 and PI3K/AKT inhibitors might be useful in the treatment of DLBCL and additional B-lymphoid malignancies with increased PDE4B expression.

The molecular signature of mediastinal large B-cell lymphoma differs from that of other diffuse large B-cell lymphomas and shares features with classical Hodgkin lymphoma

Mediastinal large B-cell lymphoma (MLBCL) is a recently identified subtype of diffuse large B-cell lymphoma (DLBCL) that characteristically presents as localized tumors in young female patients. Although MLBCL has distinctive pathologic features, it clinically resembles the nodular sclerosis subtype of classical Hodgkin lymphoma (cHL). To elucidate the molecular features of MLBCL, we compared the gene expression profiles of newly diagnosed MLBCL and DLBCL and developed a classifier of these diseases. MLBCLs had low levels of expression of multiple components of the B-cell receptor signaling cascade, a profile resembling that of Reed-Sternberg cells of cHL. Like cHLs, MLBCLs also had high levels of expression of the interleukin-13 (IL-13) receptor and downstream effectors of IL-13 signaling (Janus kinase-2 [JAK2] and signal transducer and activator of transcription-1 [STAT1]), tumor necrosis factor (TNF) family members, and TNF receptor-associated factor-1 (TRAF1). Increased expression of STAT1 and TRAF1 in MLBCL was confirmed by immunohistochemistry. Given the TRAF1 expression and known link to nuclear factor-kappa B (NF- kappa B), MLBCLs were also evaluated for nuclear translocation of c-REL protein. In almost all cases, c-REL was localized to the nucleus, consistent with activation of the NF-kappa B pathway. These studies identify a molecular link between MLBCL and cHL and a shared survival pathway.

Outpatient use of low molecular weight heparin (Dalteparin) for the treatment of deep vein thrombosis of the upper extremity

Upper extremity deep vein thrombosis (DVT) is now recognized as a major cause of morbidity and mortality. There is little information regarding the most effective treatment of this condition. We report a prospective cohort study of the use of low molecular weight heparin (LMWH) in the outpatient management of upper extremity DVT. Forty-six patients were managed as outpatients for objectively documented upper extremity DVT with dalteparin (200 aXa u/kg), for a minimum of five days. Warfarin was usually initiated on the first day with a target INR of 2.0-3.0. Most patients had an underlying malignancy or a history of a central line. All patients were followed for 12 weeks from diagnosis. Only one patient had a major bleed. No patients developed pulmonary emboli. One patient had a recurrence of DVT during the treatment with LMWH with extension of the existing thrombus. Seven patients died, all due to their underlying disease. This study supports the safety and effectiveness of dalteparin in the treatment of upper extremity DVT. Given that these patients were treated as outpatients, there is a potential for huge cost savings.

Receptor recognition sites reside in both lobes of human serum transferrin

The binding of iron by transferrin leads to a significant conformational change in each lobe of the protein. Numerous studies have shown that the transferrin receptor discriminates between iron-saturated and iron-free transferrin and that it modulates the release of iron. Given these observations, it seems likely that there is contact between each lobe of transferrin and the receptor. This is the case with chicken transferrin, in which it has been demonstrated unambiguously that both lobes are required for binding and iron donation to occur [Brown-Mason and Woodworth (1984) J. Biol. Chem. 259, 1866-1873]. Further support to this contention is added by the ability of both N- and C-domain-specific monoclonal antibodies to block the binding of a solution containing both lobes [Mason, Brown and Church (1987) J. Biol. Chem. 262, 9011-9015]. In the present study a similar conclusion is reached for the binding of human serum transferrin to the transferrin receptor. With the use of recombinant N- and C-lobes of human transferrin produced in a mammalian expression system, we show that both lobes are required to achieve full binding. (Production of recombinant C-lobe in the baby hamster kidney cell system is reported here for the first time.) Each lobe is able to donate iron to transferrin receptors on HeLa S3 cells in the presence of the contralateral lobe. The results are not identical with the chicken system, because the C-lobe alone shows a limited ability to bind to receptors and to donate iron. Further complications arise from the relatively weak re-association between the two lobes of human transferrin compared with the re-association of the ovotransferrin lobes. However, domain-specific monoclonal antibodies to either lobe block the binding of N- and C-lobe mixtures in the human system, thus substantiating the need for both.

Association of the two lobes of ovotransferrin is a prerequisite for receptor recognition. Studies with recombinant ovotransferrins

Different recombinant N-lobes of chicken ovotransferrin (oTF/2N) have been isolated from the tissue-culture medium of baby hamster kidney cells transfected with the plasmid pNUT containing the relevant DNA coding sequence. Levels of up to 40, 55 and 30 mg/1 oTF/2N were obtained for constructs defining residues 1-319, 1-332 and 1-337-(Ala)3 respectively. In addition, a full-length non-glycosylated oTF was expressed at a maximum of 80 mg/1 and a foreshortened oTF consisting of residues 1-682 was expressed at a level of 95 mg/l. These preparations were then used to produce, proteolytically, two different C-lobes (oTF/2C) comprising residues 342-686 and 342-682. The purified recombinant N-lobes (oTF/2N) are similar to the proteolytically derived half-molecule with regard to immunoreactivity and spectral properties; they show some interesting differences in thermal stability. A sequence analysis of the cDNA revealed six changes at the nucleotide level that led to six differences in the amino acid sequence compared with that reported by Jeltsch and Chambon [(1982) Eur. J. Biochem. 122, 291-295]. Electrospray mass spectrometry gives results consistent with these six changes. Interaction between the various N- and C-lobes was measured by titration calorimetry. Studies show that only those lobes that associate in solution are able to bind to the receptors on chick embryo red blood cells. These findings do not support a previous report by Oratore et al.

Expression of glycosylated and nonglycosylated human transferrin in mammalian cells. Characterization of the recombinant proteins with comparison to three commercially available transferrins

The coding sequence for human serum transferrin was assembled from restriction fragments derived from a full-length cDNA clone isolated from a human liver cDNA library. The assembled clone was inserted into the expression vector pNUT and stably transfected into transformed baby hamster kidney (BHK) cells, leading to secretion of up to 125 mg/L recombinant protein into the tissue culture medium. As judged by mobility on NaDodSO4-PAGE, immunoreactivity, spectral properties (indicative of correct folding and iron binding), and the ability to bind to receptors on a human cell line, initial studies showed that the recombinant transferrin, is identical to three commercial human serum transferrin samples. Electrospray mass spectrometry (ESMS), anion-exchange chromatography, and urea gel analysis showed that the recombinant protein has an extremely complex carbohydrate pattern with 16 separate masses ranging from 78,833 to 80,802 daltons. Mutation of the two asparagine carbohydrate linkage sites to aspartic acid residues led to the expression and secretion of up to 25 mg/L nonglycosylated transferrin. ESMS, anion-exchange chromatography, and urea gel analysis showed a single molecular species that was consistent with the expected theoretical mass of 75,143 daltons. In equilibrium binding experiments, the nonglycosylated mutant bound to HeLa S3 cells with the same avidity and to the same extent as the glycosylated protein and the three commercial samples. These studies demonstrate conclusively that carbohydrate has no role in this function.