The Impact of Age and Sex in DLBCL: Systems Biology Analyses Identify Distinct Molecular Changes and Signaling Networks

Potential molecular alterations based on age and sex are not well defined in diffuse large B-cell lymphoma (DLBCL). We examined global transcriptome DLBCL data from The Cancer Genome Atlas (TCGA) via a systems biology approach to determine the molecular differences associated with age and sex. Collectively, sex and age revealed striking transcriptional differences with older age associated with decreased metabolism and telomere functions and female sex was associated with decreased interferon signaling, transcription, cell cycle, and PD-1 signaling. We discovered that the key genes for most groups strongly regulated immune function activity. Furthermore, older females were predicted to have less DLBCL progression versus older males and young females. Finally, analyses in systems biology revealed that JUN and CYCS signaling were the most critical factors associated with tumor progression in older and male patients. We identified important molecular perturbations in DLBCL that were strongly associated with age and sex and were predicted to strongly influence tumor progression.

A phase II study of cyclophosphamide, etoposide, vincristine and prednisone (CEOP) Alternating with Pralatrexate (P) as front line therapy for patients with peripheral T-cell lymphoma (PTCL): final results from the T- cell consortium trial

Peripheral T-cell lymphomas (PTCL) have suboptimal outcomes using conventional CHOP (cyclophosphamide, doxorubicin, vincristine, prednisone) chemotherapy. The anti-folate pralatrexate, the first drug approved for patients with relapsed/refractory PTCL, provided a rationale to incorporate it into the front-line setting. This phase 2 study evaluated a novel front-line combination whereby cyclophosphamide, etoposide, vincristine and prednisone (CEOP) alternated with pralatrexate (CEOP-P) in PTCL. Patients achieving a complete or partial remission (CR/PR) were eligible for consolidative stem cell transplantation (SCT) after 4 cycles. Thirty-three stage II-IV PTCL patients were treated: 21 PTCL-not otherwise specified (64%), 8 angioimmunoblastic T cell lymphoma (24%) and 4 anaplastic large cell lymphoma (12%). The majority (61%) had stage IV disease and 46% were International Prognostic Index high/intermediate or high risk. Grade 3-4 toxicities included anaemia (27%), thrombocytopenia (12%), febrile neutropenia (18%), mucositis (18%), sepsis (15%), increased creatinine (12%) and liver transaminases (12%). Seventeen patients (52%) achieved a CR. The 2-year progression-free survival and overall survival, were 39% (95% confidence interval 21-57) and 60% (95% confidence interval 39-76), respectively. Fifteen patients (45%) (12 CR) received SCT and all remained in CR at a median follow-up of 21·5 months. CEOP-P did not improve outcomes compared to historical data using CHOP. Defining optimal front line therapy in PTCL continues to be a challenge and an unmet need.

Hematologic Malignancies in Pregnancy: Management Guidelines From an International Consensus Meeting

PURPOSE

The incidence of hematologic malignancies during pregnancy is 0.02%. However, this figure is increasing, as women delay conception until a later age. Systemic symptoms attributed to the development of a hematologic cancer may overlap with physiologic changes of pregnancy. A favorable prognosis is contingent upon early diagnosis and treatment. Therefore, a high index of suspicion is required by health care providers. Although timely, accurate diagnosis followed by appropriate staging is essential and should not be delayed due to pregnancy, management guidelines are lacking due to insufficient evidence-based research. Consequently, treatment is delayed, posing significant risks to maternal and fetal health, and potential pregnancy termination. This report provides guidelines for clinical management of hematologic cancers during the perinatal period, which were developed by a multidisciplinary team including an experienced hematologist/oncologist, a high-risk obstetrics specialist, a neonatologist, and experienced nurses, social workers, and psychologists.

METHODS

These guidelines were developed by experts in the field during the first International Consensus Meeting of Prenatal Hematologic Malignancies, which took place in Leuven, Belgium, on May 23, 2014.

RESULTS AND CONCLUSION

This consensus summary equips health care professionals with novel diagnostic and treatment methodologies that aim for optimal treatment of the mother, while protecting fetal and pediatric health.

A Phase I/II Multicenter, Open-Label Study of the Oral Histone Deacetylase Inhibitor Abexinostat in Relapsed/Refractory Lymphoma

PURPOSE

Additional targeted therapeutics are needed for the treatment of lymphoma. Abexinostat is an oral pan-histone deacetylase inhibitor (HDACi) displaying potent activity in preclinical models. We conducted a multicenter phase I/II study (N = 55) with single-agent abexinostat in relapsed/refractory lymphoma.

EXPERIMENTAL DESIGN

In phase I, 25 heavily pretreated patients with any lymphoma subtype received oral abexinostat ranging from 30 to 60 mg/m(2) twice daily 5 days/week for 3 weeks or 7 days/week given every other week. Phase II evaluated abexinostat at the maximum tolerated dose in 30 patients with relapsed/refractory follicular lymphoma or mantle cell lymphoma.

RESULTS

The recommended phase II dose was 45 mg/m(2) twice daily (90 mg/m(2) total), 7 days/week given every other week. Of the 30 follicular lymphoma and mantle cell lymphoma patients enrolled in phase II, 25 (14 follicular lymphoma, 11 mantle cell lymphoma) were response-evaluable. Tumor size was reduced in 86% of follicular lymphoma patients with an investigator-assessed ORR of 64.3% for evaluable patients [intent-to-treat (ITT) ORR 56.3%]. Median duration of response was not reached, and median progression-free survival (PFS) was 20.5 months (1.2-22.3+). Of responding follicular lymphoma patients, 89% were on study/drug >8 months. In mantle cell lymphoma, the ORR was 27.3% for evaluable patients (ITT ORR 21.4%), and median PFS was 3.9 months (range, 0.1-11.5). Grade 3-4 treatment-related adverse events (phase II) with ≥ 10% incidence were thrombocytopenia (20%), fatigue (16.7%), and neutropenia (13.3%) with rare QTc prolongation and no deaths.

CONCLUSIONS

The pan-HDACi, abexinostat, was overall well tolerated and had significant clinical activity in follicular lymphoma, including highly durable responses in this multiply relapsed patient population.

Gray zone lymphoma with features intermediate between classical Hodgkin lymphoma and diffuse large B-cell lymphoma: characteristics, outcomes, and prognostication among a large multicenter cohort

Gray zone lymphoma (GZL) with features between classical Hodgkin lymphoma and diffuse large B-cell lymphoma (DLBCL) is a recently recognized entity reported to present primarily with mediastinal disease (MGZL). We examined detailed clinical features, outcomes, and prognostic factors among 112 GZL patients recently treated across 19 North American centers. Forty-three percent of patients presented with MGZL, whereas 57% had non-MGZL (NMGZL). NMGZL patients were older (50 versus 37 years, P = 0.0001); more often had bone marrow involvement (19% versus 0%, P = 0.001); >1 extranodal site (27% versus 8%, P = 0.014); and advanced stage disease (81% versus 13%, P = 0.0001); but they had less bulk (8% versus 44%, P = 0.0001), compared with MGZL patients. Common frontline treatments were cyclophosphamide-doxorubicin-vincristine-prednisone +/- rituximab (CHOP+/-R) 46%, doxorubicin-bleomycin-vinblastine-dacarbazine +/- rituximab (ABVD+/-R) 30%, and dose-adjusted etoposide-doxorubicin-cyclophosphamide-vincristine-prednisone-rituximab (DA-EPOCH-R) 10%. Overall and complete response rates for all patients were 71% and 59%, respectively; 33% had primary refractory disease. At 31-month median follow-up, 2-year progression-free survival (PFS) and overall survival rates were 40% and 88%, respectively. Interestingly, outcomes in MGZL patients seemed similar compared with that of NMGZL patients. On multivariable analyses, performance status and stage were highly prognostic for survival for all patients. Additionally, patients treated with ABVD+/-R had markedly inferior 2-year PFS (22% versus 52%, P = 0.03) compared with DLBCL-directed therapy (CHOP+/-R and DA-EPOCH-R), which persisted on Cox regression (hazard ratio, 1.88; 95% confidence interval, 1.03-3.83; P = 0.04). Furthermore, rituximab was associated with improved PFS on multivariable analyses (hazard ratio, 0.35; 95% confidence interval, 0.18-0.69; P = 0.002). Collectively, GZL is a heterogeneous and likely more common entity and often with nonmediastinal presentation, whereas outcomes seem superior when treated with a rituximab-based, DLBCL-specific regimen.

Proton irradiation impacts age-driven modulations of cancer progression influenced by immune system transcriptome modifications from splenic tissue

Age plays a crucial role in the interplay between tumor and host, with additional impact due to irradiation. Proton irradiation of tumors induces biological modulations including inhibition of angiogenic and immune factors critical to 'hallmark' processes impacting tumor development. Proton irradiation has also provided promising results for proton therapy in cancer due to targeting advantages. Additionally, protons may contribute to the carcinogenesis risk from space travel (due to the high proportion of high-energy protons in space radiation). Through a systems biology approach, we investigated how host tissue (i.e. splenic tissue) of tumor-bearing mice was altered with age, with or without whole-body proton exposure. Transcriptome analysis was performed on splenic tissue from adolescent (68-day) versus old (736-day) C57BL/6 male mice injected with Lewis lung carcinoma cells with or without three fractionations of 0.5 Gy (1-GeV) proton irradiation. Global transcriptome analysis indicated that proton irradiation of adolescent hosts caused significant signaling changes within splenic tissues that support carcinogenesis within the mice, as compared with older subjects. Increases in cell cycling and immunosuppression in irradiated adolescent hosts with CDK2, MCM7, CD74 and RUVBL2 indicated these were the key genes involved in the regulatory changes in the host environment response (i.e. the spleen). Collectively, these results suggest that a significant biological component of proton irradiation is modulated by host age through promotion of carcinogenesis in adolescence and resistance to immunosuppression, carcinogenesis and genetic perturbation associated with advancing age.

Role of cytotoxic therapy with hematopoietic cell transplantation in the treatment of Hodgkin lymphoma: guidelines from the American Society for Blood and Marrow Transplantation

The role of hematopoietic cell transplantation (HCT) in the therapy of Hodgkin lymphoma (HL) in pediatric and adult patients is reviewed and critically evaluated in this systematic evidence-based review. Specific criteria were used for searching the published literature and for grading the quality and strength of the evidence and the strength of the treatment recommendations. Treatment recommendations based on the evidence are included and were reached unanimously by a panel of HL experts. Both autologous and allogeneic HCT offer a survival benefit in selected patients with advanced or relapsed HL and are currently part of standard clinical care. Relapse remains a significant cause of failure after both transplant approaches, and strategies to decrease the risk of relapse remain an important area of investigation.

Current therapeutic strategies and new treatment paradigms for follicular lymphoma

Follicular lymphoma (FL) is an indolent non-Hodgkin's lymphoma that remains an incurable disease for most patients. It is responsive to a variety of different treatments, however it follows a pattern of relapsing and remitting disease. Traditional therapeutic options for patients with untreated FL include expectant observation for asymptomatic and low tumor burden and multiagent cytotoxic chemotherapy for symptomatic and/or high tumor burden. Biologics have become an integral part of therapy with agents that target B lymphocytes, including monoclonal anti-CD20 antibodies and radiolabeled anti-CD20 antibodies. Treatment response to cytotoxic and biologic therapy is high initially; however, with subsequent treatments, response rate and remission duration typically decline and cumulative toxicities increase. The identification of novel targeted agents, use of stem cell transplantation, and new treatment combinations provide the opportunity to enhance patient outcomes. In this review, we critically examine standard treatment strategies for patients with newly diagnosed and relapsed or refractory FL and discuss established and emerging novel therapeutic approaches.

Multiple successful desensitizations to brentuximab vedotin: a case report and literature review

Brentuximab vedotin is an antibody-drug conjugate FDA-approved for the treatment of systemic anaplastic large-cell lymphoma (ALCL) that has relapsed after multiagent chemotherapy. At least 2 cases of hypersensitivity reactions to brentuximab vedotin have been reported, without attempted desensitization. This report describes a morbidly obese 32-year-old woman with ALCL that relapsed after autologous stem cell transplantation, who was treated on a phase II clinical study with brentuximab vedotin. After 1 dose, she experienced near-complete remission, but therapy was stopped because of severe drug-related toxicity. She then received 5 cytotoxic treatments and radiation, and ultimately experienced disease progression. The patient was rechallenged with brentuximab vedotin approximately 28 months after initial exposure and tolerated the dose well, but experienced a significant allergic reaction with the next dose. High-dose steroid and antihistamine prophylaxis administered 50 minutes before the subsequent brentuximab vedotin infusion was unsuccessful in mitigating this reaction. Brentuximab vedotin was successfully infused according to a rapid desensitization protocol. With progressive dose titration and supportive care, the patient tolerated this therapy. She received 11 doses through a rapid desensitization protocol and experienced a durable disease remission.

The role of FDG-PET in defining prognosis of Hodgkin lymphoma for early-stage disease

Given the excellent survival rates for early-stage Hodgkin lymphoma (HL), the young age of many patients, and concerns regarding acute and late treatment-related toxicities, there is a desire to have a predictive tool that enables therapy to be tailored toward the individual patient. Early (or interim) (18)F-fluorodeoxyglucose positron emission tomography with computerized tomography (FDG-PET/CT), as a test of tumor sensitivity to ongoing/planned therapy, has been shown to be prognostic for survival in HL. Based on results of interim FDG-PET/CT, therapy may be subsequently modified through minimization or via intensification for low- and high-risk patient populations, respectively (ie, response-adapted therapy). Important data have been generated to standardize the interpretability and reproducibility of interim FDG-PET/CT (eg, the Deauville 5-point system), and observational and noncontrolled prospective studies have produced evidence supporting the hypothesis that response-adapted therapy may potentially serve as a predictive tool. Furthermore, results from noninferiority phase 3 clinical trials randomizing early-stage HL patients with negative interim FDG-PET/CT to combined modality therapy versus chemotherapy alone have been reported. The current collective findings from these randomized early-stage HL studies have shown that acute relapse rates are lower with combined modality therapy, even in patients with negative interim FDG-PET/CT. Additional randomized response-adapted studies are ongoing and novel FDG-PET/CT applications involving quantitative techniques and innovative imaging modalities are being investigated to identify more robust imaging biomarkers. Treatment of early-stage HL remains a clinical management choice for physicians and patients to make with consideration of acute and long-term outcomes.

The novel organic arsenical darinaparsin induces MAPK-mediated and SHP1-dependent cell death in T-cell lymphoma and Hodgkin lymphoma cells and human xenograft models

PURPOSE

Darinaparsin (Zio-101) is a novel organic arsenical compound with encouraging clinical activity in relapsed/refractory T-cell lymphoma (TCL) and Hodgkin lymphoma (HL); however, little is known about its mechanism of action.

EXPERIMENTAL DESIGN

TCL cell lines (Jurkat, Hut78, and HH) and HL cell lines (L428, L540, and L1236) were examined for in vitro cell death by MTT assay and Annexin V-based flow cytometry. Jurkat and L540-derived xenografts in SCID mice were examined for in vivo tumor inhibition and survival. Biologic effects of darinaparsin on the MAPK pathway were investigated using pharmacologic inhibitors, RNAi and transient transfection for overexpression for SHP1 and MEK.

RESULTS

Darinaparsin treatment resulted in time- and dose-dependent cytotoxicity and apoptosis in all TCL and HL cell lines. In addition, darinaparsin had more rapid, higher, and sustained intracellular arsenic levels compared with arsenic trioxide via mass spectrometry. In vivo experiments with Jurkat (TCL) and L540 (HL)-derived lymphoma xenografts showed significant inhibition of tumor growth and improved survival in darinaparsin-treated SCID mice. Biologically, darinaparsin caused phosphorylation of ERK (and relevant downstream substrates) primarily by decreasing the inhibitory SHP1 phosphatase and coimmunoprecipitation showed significant ERK/SHP1 interaction. Furthermore, ERK shRNA knockdown or constitutive overexpression of SHP1 resulted in increased apoptosis, whereas cotreatment with pharmacologic MEK inhibitors resulted in synergistic cell death. Conversely, SHP1 blockade (via pharmacologic inhibition or RNAi) and MEK constitutive activation decreased darinaparsin-related cell death.

CONCLUSIONS

Altogether, these data show that darinaparsin is highly active in HL and TCL and its activity is dependent primarily on MAPK mechanisms.

Peripheral T-cell lymphomas in a large US multicenter cohort: prognostication in the modern era including impact of frontline therapy

BACKGROUND

Optimal frontline therapy for peripheral T-cell lymphoma (PTCL) in the modern era remains unclear.

PATIENTS AND METHODS

We examined patient characteristics, treatment, and outcomes among 341 newly diagnosed PTCL patients from 2000 to 2011. Outcome was compared with a matched cohort of diffuse large B-cell lymphoma (DLBCL) patients, and prognostic factors were assessed using univariate and multivariate analyses.

RESULTS

PTCL subtypes included PTCL, not otherwise specified (PTCL-NOS) (31%), anaplastic large T-cell lymphoma (ALCL) (26%), angioimmunoblastic T-cell lymphoma (23%), NK/T-cell lymphoma (7%), acute T-cell leukemia/lymphoma (6%), and other (7%). Median age was 62 years (range 18-95 years), and 74% had stage III-IV disease. Twenty-three (7%) patients received only palliative care whereas 318 received chemotherapy: CHOP-like regimens (70%), hyperCVAD/MA (6%), or other (18%). Thirty-three patients (10%) underwent stem-cell transplantation (SCT) in first remission. The overall response rate was 73% (61% complete); 24% had primary refractory disease. With 39-month median follow-up, 3-year progression-free survival (PFS) and overall survival (OS) were 32% and 52%. PFS and OS for PTCL patients were significantly inferior to matched patients with DLBCL. On multivariate analysis, stage I-II disease was the only significant pretreatment prognostic factor [PFS: hazard ratio (HR) 0.54, 95% confidence interval (CI) 0.34-0.85, P = 0.007; OS: HR 0.42, 95% CI 0.22-0.78, P = 0.006]. ALK positivity in ALCL was prognostic on univariate analysis, but lost significance on multivariate analysis. The most dominant prognostic factor was response to initial therapy (complete response versus other), including adjustment for stage and SCT [PFS: HR 0.19, 95% CI 0.14-0.28, P < 0.0001; OS: HR 0.26, 95% CI 0.17-0.40, P < 0.0001]. No overall survival difference was observed based on choice of upfront regimen or SCT in first remission.

CONCLUSIONS

This analysis identifies early-stage disease and initial treatment response as dominant prognostic factors in PTCL. No clear benefit was observed for patients undergoing consolidative SCT. Novel therapeutic approaches for PTCL are critically needed.

Inhibition of bromodomain proteins for the treatment of human diffuse large B-cell lymphoma

PURPOSE

Approximately 50% of patients with diffuse large B-cell lymphoma (DLBCL) enter long-term remission after standard chemotherapy. Patients with DLBCL who do not respond to chemotherapy have few treatment options. There remains a critical need to identify effective and targeted therapeutics for DLBCL.

EXPERIMENTAL DESIGN

Recent studies have highlighted the incidence of increased c-MYC protein in DLBCL and the correlation between high levels of c-MYC protein and poor survival prognosis of patients with DLBCL, suggesting that c-MYC is a compelling target for DLBCL therapy. The small molecule JQ1 suppresses c-MYC expression through inhibition of the bromodomain and extra-terminal (BET) family of bromodomain proteins. We investigated whether JQ1 can inhibit proliferation of DLBCL cells in culture and xenograft models in vivo.

RESULTS

We show that JQ1 at nanomolar concentrations efficiently inhibited proliferation of human DLBCL cells in a dose-dependent manner regardless of their molecular subtypes, suggesting a broad effect of JQ1 in DLBCL. The initial G1 arrest induced by JQ1 treatment in DLBCL cells was followed by either apoptosis or senescence. The expression of c-MYC was suppressed as a result of JQ1 treatment from the natural, chromosomally translocated, or amplified loci. Furthermore, JQ1 treatment significantly suppressed growth of DLBCL cells engrafted in mice and improved survival of engrafted mice.

CONCLUSION

Our results demonstrate that inhibition of the BET family of bromodomain proteins by JQ1 has potential clinical use in the treatment of DLBCL.

The impact of race, age, and sex in follicular lymphoma: A comprehensive SEER analysis across consecutive treatment eras

The impact of race/ethnicity and the additional factors of age, sex, and socioeconomic status (SES) on follicular lymphoma (FL) outcomes have not been comprehensively studied and are not well defined. We examined population-based FL data from >18,000 patients in SEER-13 (1992-2009) investigating race/ethnicity and the impact of relevant factors including sex, age, and SES. Further, we compared data over two consecutive periods: Era-1 (1992-2000, n = 8,355) and Era-2 (2001-2009, n = 10,475). We identified 18,830 FL patients (White: n = 15,116; Hispanic: n = 1,627; Asian/Pacific Islander (A/PI): n = 1,002; and Black: n = 846). Median ages (years) differed significantly by race/ethnicity: White: 62.1, Hispanic: 57.3, A/PI: 60.7, and Black: 56.8 (P < 0.01 each race versus White). Overall survival (OS) was superior in Era-2 versus Era-1 for all patients (5-year: 76.7% versus 67.4%, respectively, P < 0.001). Further, survival was significantly improved for all age groups <80 years, for males (P = 0.0019), and females (P < 0.001) across eras. Females had superior OS compared with males in Era-1 (P = 0.004), but not in Era-2. Additionally, all races, except A/PI, had improved 5-year OS rates from Era-1 to Era-2. Finally, OS improved across eras for lower and higher SES populations; however those with higher SES were superior to lower SES patients in both eras. In conclusion, and in the largest comprehensive evaluation of US-based FL patients to date, we show that despite improvements in OS for FL over time, critical disparities across races/ethnicities, sex, and age groups remain in the modern era and warrant further studies.

Frontline bortezomib and rituximab for the treatment of newly diagnosed high tumour burden indolent non-Hodgkin lymphoma: a multicentre phase II study

There is a lack of published data examining non-cytotoxic options for the frontline treatment of patients with high-tumour burden (HTB) indolent non-Hodgkin lymphoma (iNHL). We completed a multicentre phase II study for patients with untreated HTB iNHL (NCT00369707) consisting of three induction cycles of weekly bortezomib and rituximab followed by an abbreviated consolidation. Forty-two patients were treated and all were evaluable; the most common histology was follicular lymphoma (FL) (n = 33, 79%). Patient characteristics included median age 62 years (40-86); 38% bulky disease; 19% malignant effusions; 91% advanced-stage disease; and median FL International Prognostic Index (FLIPI) score was 3. Therapy was well tolerated with few grade 3/4 toxicities including minimal neurotoxicity. On intent-to-treat, the overall response rate (ORR) at end of therapy was 70% with a complete remission (CR) rate of 40% (FL: ORR 76%, CR 44%). With 50-month median follow-up, 4-year progression-free survival (PFS) was 44% with 4-year overall survival (OS) of 87% (FL: 44% and 97%, respectively). Four-year PFS for FLIPI 0-2 vs. 3-5 was 60% vs. 26% respectively (P = 0·02), with corresponding OS rates of 92% and 81% respectively (P = 0·16). Collectively, bortezomib/rituximab is a non-cytotoxic therapeutic regimen that was well tolerated and resulted in long-term survival rates approximating prior rituximab/cytotoxic chemotherapy series for untreated HTB FL.

A multicentre study of primary breast diffuse large B-cell lymphoma in the rituximab era

Primary breast diffuse large B-cell lymphoma (DLBCL) is a rare subtype of non-Hodgkin lymphoma (NHL) with limited data on pathology and outcome. A multicentre retrospective study was undertaken to determine prognostic factors and the incidence of central nervous system (CNS) relapses. Data was retrospectively collected on patients from 8 US academic centres. Only patients with stage I/II disease (involvement of breast and localized lymph nodes) were included. Histologies apart from primary DLBCL were excluded. Between 1992 and 2012, 76 patients met the eligibility criteria. Most patients (86%) received chemotherapy, and 69% received immunochemotherapy with rituximab; 65% received radiation therapy and 9% received prophylactic CNS chemotherapy. After a median follow-up of 4·5 years (range 0·6-20·6 years), the Kaplan-Meier estimated median progression-free survival was 10·4 years (95% confidence interval [CI] 5·8-14·9 years), and the median overall survival was 14·6 years (95% CI 10·2-19 years). Twelve patients (16%) had CNS relapse. A low stage-modified International Prognostic Index (IPI) was associated with longer overall survival. Rituximab use was not associated with a survival advantage. Primary breast DLBCL has a high rate of CNS relapse. The stage-modified IPI score is associated with survival.

FDG-PET imaging for Hodgkin lymphoma: current use and future applications

A significant amount of data has been published over the past decade regarding the clinical utility of F-fluorodeoxyglucose positron emission tomography (FDG-PET) in the diagnosis and management of Hodgkin lymphoma (HL). This includes studies examining interim FDG-PET, which has been shown to be a strong tool for predicting relapse and survival, especially in advanced- stage HL. Despite progress, a number of questions remain regard- ing the precise role and value of FDG-PET in the diagnosis, risk stratification, and management of HL. These questions include the need for concomitant contrast enhanced computed tomography with FDG-PET, reproducibility and interpretability of FDG-PET, optimal imaging for the treatment surveillance of HL following definitive treatment, and the use of FDG-PET for patients with relapsed/refractory disease, including stem cell transplantation. In this review, these issues are critically examined and the study designs and results of observational and prospective FDG-PET response-adaptive clinical trials in HL are described in detail. In addition, novel techniques and future applications of FDG- PET, such as metabolic tumor volume, tumor proliferation via 3'-deoxy-3'-18F-fluorothymidine, and integrated PET/magnetic resonance imaging are discussed.

Paradoxical regulation of hypoxia inducible factor-1α (HIF-1α) by histone deacetylase inhibitor in diffuse large B-cell lymphoma

Hypoxia inducible factor (HIF) is important in cancer, as it regulates various oncogenic genes as well as genes involved in cell survival, proliferation, and migration. Elevated HIF-1 protein promotes a more aggressive tumor phenotype, and greater HIF-1 expression has been demonstrated to correlate with poorer prognosis, increased risk of metastasis and increased mortality. Recent reports suggest that HIF-1 activates autophagy, a lysosomal degradation pathway which may promote tumor cell survival. We show here that HIF-1α expression is constitutively active in multiple diffuse large B cell lymphoma (DLBCL) cell lines under normoxia and it is regulated by the PI3K/AKT pathway. PCI-24781, a pan histone deacetylase inhibitor (HDACI), enhanced accumulation of HIF-1α and induced autophagy initially, while extended incubation with the drug resulted in inhibition of HIF-1α. We tested the hypothesis that PCI-24781- induced autophagy is mediated by HIF-1α and that inhibition of HIF-1α in these cells results in attenuation of autophagy and decreased survival. We also provide evidence that autophagy serves as a survival pathway in DLBCL cells treated with PCI-24781 which suggests that the use of autophagy inhibitors such as chloroquine or 3-methyl adenine in combination with PCI-24781 may enhance apoptosis in lymphoma cells.