Lisa Giulino-Roth

Flow sorting and exome sequencing reveal the oncogenome of primary Hodgkin and Reed-Sternberg cells

Classical Hodgkin lymphoma (cHL) is characterized by sparsely distributed Hodgkin and Reed-Sternberg (HRS) cells amid reactive host background, complicating the acquisition of neoplastic DNA without extensive background contamination. We overcame this limitation by using flow-sorted HRS and intratumor T cells and optimized low-input exome sequencing of 10 patient samples to reveal alterations in genes involved in antigen presentation, chromosome integrity, transcriptional regulation, and ubiquitination. β-2-microglobulin (B2M) is the most commonly altered gene in HRS cells, with 7 of 10 cases having inactivating mutations that lead to loss of major histocompatibility complex class I (MHC-I) expression. Enforced wild-type B2M expression in a cHL cell line restored MHC-I expression. In an extended cohort of 145 patients, the absence of B2M protein in the HRS cells was associated with lower stage of disease, younger age at diagnosis, and better overall and progression-free survival. B2M-deficient cases encompassed most of the nodular sclerosis subtype cases and only a minority of mixed cellularity cases, suggesting that B2M deficiency determines the tumor microenvironment and may define a major subset of cHL that has more uniform clinical and morphologic features. In addition, we report previously unknown genetic alterations that may render selected patients sensitive to specific targeted therapies.

Targeted genomic sequencing of pediatric Burkitt lymphoma identifies recurrent alterations in antiapoptotic and chromatin-remodeling genes

To ascertain the genetic basis of pediatric Burkitt lymphoma (pBL), we performed clinical-grade next-generation sequencing of 182 cancer-related genes on 29 formalin-fixed, paraffin embedded primary pBL samples. Ninety percent of cases had at least one mutation or genetic alteration, most commonly involving MYC and TP53. EBV(-) cases were more likely than EBV(+) cases to have multiple mutations (P < .0001). Alterations in tumor-related genes not previously described in BL were identified. Truncating mutations in ARID1A, a member of the SWI/SNF nucleosome remodeling complex, were seen in 17% of cases. MCL1 pathway alterations were found in 22% of cases and confirmed in an expanded panel. Other clinically relevant genomic alterations were found in 20% of cases. Our data suggest the roles of MCL1 and ARID1A in BL pathogenesis and demonstrate that comprehensive genomic profiling may identify additional treatment options in refractory disease.

Ten‐year follow‐up of pediatric patients with non‐hodgkin lymphoma treated with allogeneic or autologous stem cell transplantation

Autologous or allogeneic hematopoietic stem cell transplant (SCT) is often considered in patients with relapsed or refractory non‐Hodgkin lymphoma (NHL) but there are limited data on the use of SCT for the treatment of NHL in the pediatric setting.

Rituximab pharmacokinetics in children and adolescents with de novo intermediate and advanced mature B-cell lymphoma/leukaemia: a Children's Oncology Group report.

The ANHL01P1 trial was undertaken to determine pharmacokinetics and safety following the addition of rituximab to French‐American‐British/Lymphome Malins de Burkitt (FAB/LMB96) chemotherapy in 41 children and adolescents with Stage III/IV mature B‐cell lymphoma/leukaemia. Patients received rituximab (375 mg/m2) days −2 and 0 of two induction cycles and day 0 of two consolidation cycles. Highest peak levels were achieved following the second dose of each induction cycle [299 ± 19 and 384 ± 25 μg/ml (Group‐B); 245 ± 31 and 321 ± 32 μg/ml (Group‐C)] with sustained troughs and t½ of 26–29 d. Rituximab can be safely added to FAB chemotherapy with high early rituximab peak/trough levels and a long t½.

Outcomes of adults and children with primary mediastinal B-cell lymphoma treated with dose-adjusted EPOCH-R

Treatment with dose‐adjusted EPOCH (etoposide, doxorubicin, cyclophosphamide, vincristine, prednisone) chemotherapy and rituximab (DA‐EPOCH‐R) has become the standard of care for primary mediastinal B‐cell lymphoma (PMBCL) at many institutions despite limited data in the multi‐centre setting. We report a large, multi‐centre retrospective analysis of children and adults with PMBCL treated with DA‐EPOCH‐R to characterize outcomes and evaluate prognostic factors. We assessed 156 patients with PMBCL treated with DA‐EPOCH‐R across 24 academic centres, including 38 children and 118 adults. All patients received at least one cycle of DA‐EPOCH‐R. Radiation therapy was administered in 14·9% of patients. With median follow‐up of 22·6 months, the estimated 3‐year event‐free survival (EFS) was 85·9% [95% confidence interval (CI) 80·3–91·5] and overall survival was 95·4% (95% CI 91·8–99·0). Outcomes were not statistically different between paediatric and adult patients. Thrombotic complications were reported in 28·2% of patients and were more common in paediatric patients (45·9% vs. 22·9%, P = 0·011). Seventy‐five per cent of patients had a negative fluorodeoxyglucose positron emission tomography (FDG‐PET) scan at the completion of DA‐EPOCH‐R, defined as Deauville score 1–3. Negative FDG‐PET at end‐of‐therapy was associated with improved EFS (95·4% vs. 54·9%, P < 0·001). Our data support the use of DA‐EPOCH‐R for the treatment of PMBCL in children and adults. Patients with a positive end‐of‐therapy FDG‐PET scan have an inferior outcome.

Inhibition of Hsp90 Suppresses PI3K/AKT/mTOR Signaling and Has Antitumor Activity in Burkitt Lymphoma

Hsp90 is a molecular chaperone that protects proteins, including oncogenic signaling complexes, from proteolytic degradation. PU-H71 is a next-generation Hsp90 inhibitor that preferentially targets the functionally distinct pool of Hsp90 present in tumor cells. Tumors that are driven by the MYC oncoprotein may be particularly sensitive to PU-H71 due to the essential role of Hsp90 in the epichaperome, which maintains the malignant phenotype in the setting of MYC. Burkitt lymphoma (BL) is an aggressive B-cell lymphoma characterized by MYC dysregulation. In this study, we evaluated Hsp90 as a potential therapeutic target in BL. We found that primary BL tumors overexpress Hsp90 and that Hsp90 inhibition has antitumor activity in vitro and in vivo, including potent activity in a patient-derived xenograft model of BL. To evaluate the targets of PU-H71 in BL, we performed high-affinity capture followed by proteomic analysis using mass spectrometry. We found that Hsp90 inhibition targets multiple components of PI3K/AKT/mTOR signaling, highlighting the importance of this pathway in BL. Finally, we found that the anti-lymphoma activity of PU-H71 is synergistic with dual PI3K/mTOR inhibition in vitro and in vivo. Overall, this work provides support for Hsp90 as a therapeutic target in BL and suggests the potential for combination therapy with PU-H71 and inhibitors of PI3K/mTOR. Mol Cancer Ther; 16(9); 1779–90. ©2017 AACR.

Current approaches in the management of low risk Hodgkin lymphoma in children and adolescents

The outcome for children and adolescents with low risk Hodgkin lymphoma (HL) is excellent, with event‐free survival >85% and overall survival >95%. Historically, however, treatment has come at the cost of significant long‐term toxicity from chemotherapy, radiation or a combination of these. Recent treatment strategies have focused on maintaining high event‐free and overall survival while minimizing the use of therapy associated with late effects. The strategies used to achieve this vary greatly among paediatric cooperative groups and there is no one standard treatment for children with low risk HL. This review summaries recent clinical trials in paediatric low risk HL and addresses some of the important considerations when comparing trials, including differences in the definition of low risk HL, differences in outcome among histological subtypes and varying approaches to reduce or eliminate radiation therapy. Recommendations are provided for the treatment of children with low risk HL outside the setting of a clinical trial.

Enhancer of zeste homolog 2 (EZH2) inhibitors

Abstract Dysregulation of the histone methyltransferase EZH2 plays a critical role in the development of a variety of malignancies including B-cell lymphomas. As a result, a series of small molecule inhibitors of EZH2 have been developed and studied in the pre-clinical setting. Three EZH2 inhibitors: tazemetostat (EPZ-6438), GSK2816126 and CPI-1205 have moved into phase I/phase II clinical trials in patients with non-Hodgkin lymphoma and genetically defined solid tumors. Early data from the tazemetostat trials indicate an acceptable safety profile and early signs of activity in diffuse large B-cell lymphoma and follicular lymphoma, including patients with EZH2 wild-type and mutant tumors. In this review, we present the rationale, key pre-clinical and early clinical findings of small molecule EZH2 inhibitors for use in lymphoma as well as future challenges and potential opportunities for combination therapies.

Recent molecular and therapeutic advances in B-cell non-Hodgkin lymphoma in children.

Paediatric B‐cell non‐Hodgkin lymphoma (B‐NHL) compromises a heterogeneous group of histological entities of which Burkitt lymphoma is the most common. In resource‐rich countries, the expected cure rate is in excess of 85% with application of risk‐adapted short intensive chemotherapy. In recent years, large paediatric cooperative group trials have sought to improve upon outcomes by decreasing the intensity of cytotoxic treatment as well as introducing targeted therapies, such as rituximab. These efforts have resulted in excellent outcomes, however there remains a group of high‐risk patients for whom novel treatment approaches are needed. In this review, we will summarize the recent paediatric clinical trials in B‐NHL as well as compare treatment approaches across the major cooperative groups. We will also highlight our current understanding of the molecular biology of paediatric B‐NHL with a focus on how this may help guide future rational targeted therapy.

EZH2: a potential new target in T-cell lymphoma?

Aberrant epigenetic programming is a hallmark of cancer and an attractive target for pharmacologic therapy. Unlike the genome, which is fixed, the epigenome is dynamic and amenable to therapeutic m...