Medical history, lifestyle, family history, and occupational risk factors for mantle cell lymphoma: the InterLymph Non-Hodgkin Lymphoma Subtypes Project

Outdoor air pollution and risk of incident adult haematologic cancer subtypes in a large US prospective cohort

BACKGROUND

Outdoor air pollution and particulate matter (PM) are classified as Group 1 human carcinogens for lung cancer. Pollutant associations with haematologic cancers are suggestive, but these cancers are aetiologically heterogeneous and sub-type examinations are lacking.

METHODS

The American Cancer Society Cancer Prevention Study-II Nutrition Cohort was used to examine associations of outdoor air pollutants with adult haematologic cancers. Census block group level annual predictions of particulate matter (PM2.5, PM10, PM10-2.5), nitrogen dioxide (NO2), ozone (O3), sulfur dioxide (SO2), and carbon monoxide (CO) were assigned with residential addresses. Hazard ratios (HR) and 95% confidence intervals (CI) between time-varying pollutants and haematologic subtypes were estimated.

RESULTS

Among 108,002 participants, 2659 incident haematologic cancers were identified from 1992-2017. Higher PM10-2.5 concentrations were associated with mantle cell lymphoma (HR per 4.1 μg/m3 = 1.43, 95% CI 1.08-1.90). NO2 was associated with Hodgkin lymphoma (HR per 7.2 ppb = 1.39; 95% CI 1.01-1.92) and marginal zone lymphoma (HR per 7.2 ppb = 1.30; 95% CI 1.01-1.67). CO was associated with marginal zone (HR per 0.21 ppm = 1.30; 95% CI 1.04-1.62) and T-cell (HR per 0.21 ppm = 1.27; 95% CI 1.00-1.61) lymphomas.

CONCLUSIONS

The role of air pollutants on haematologic cancers may have been underestimated previously because of sub-type heterogeneity.

Investigation of occupational risk factors for the development of non-Hodgkin's lymphoma in adults: A hospital-based case-control study

Non-Hodgkin's Lymphoma (NHL) is a malignancy of the lymphoid lineage of the hematopoietic system has worldwide, especially in developed countries. Better diagnostic and recording techniques, longer life expectancy, and greater exposure to risk factors are hypotheses for this growing incidence curve. Occupational exposures to chemical, biological, and physical agents have also been associated with NHL development, but the results are still controversial. We have investigated the occupational and lifestyle case-control study design with 214 adult patients and 452 population controls. Socio-demographic, clinical, and occupational exposure data were obtained through individual interviews with a standardized questionnaire. Clinical, laboratory, and histopathological data were obtained through medical records. Risk of NHL (any subtype), B-cell lymphoma, DLBCL, Follicular lymphoma and T-cell lymphoma was elevated among the those who had ever been exposed to any solvents, hydrocarbon solvents, pesticides, meat and meat products, and sunlight and tended to increase by years of exposure. A significant upward trend with years of exposure was detected for any solvents and hydrocarbon solvents (NHL (any subtype) p-value for trend<0.001), B-cell lymphoma (p-value for trend<0.001), and T-cell lymphoma (p-value for trend<0.023), pesticides (NHL (any subtype), p for trend<0.001) and T-cell lymphoma (p for trend<0.002), meat and meat products (NHL (any subtype) (p for trend<0.001) and DLBCL (p for trend<0.001), and sunlight (B-cell lymphoma (p for trend<0.001). The results of this study agree line with other international studies, can be extrapolated to other countries that have the same socio-demographic and occupational characteristics as Brazil and support strategies for surveillance and control of work-related cancer.

Etiology of non-Hodgkin lymphoma: A review from epidemiologic studies

Non-Hodgkin lymphoma (NHL) contributes to significant cancer burden and mortality globally. In recent years, much insight into the causes of NHL has been gained by evaluating global differences through international collaboration and data pooling. NHL comprises different subtypes that are known to behave differently, exhibit different prognoses, and start in distinct cell types (B-cell, T-cell, and NK-cell, predominantly), and there is increasing evidence that NHL subtypes have different etiologies. Classification of NHL can be complex, with varying subtype frequencies, and is a consideration when evaluating geographic differences. Because of this, international pooling of well-executed epidemiologic studies has conferred power to evaluate NHL by subtype and confidence with minimal misclassification. Given the decreasing burden in some regions while cases rise in Asia, and especially China, this report focuses on a review of the established etiology of NHL from the epidemiologic literature in recent decades, highlighting work from China. Topics covered include demographic patterns and genetic determinants including family history of NHL, as well as infection and immunosuppression, lifestyle, environment, and certain occupational exposures contributing to increased disease risk.

Incidence and survival of lymphoid neoplasms in Spain, 2002-2013: A population-based study from the Spanish Network of Cancer Registries (REDECAN)

Introduction

The aim of this study was to describe incidence, incidence trends and survival patterns of lymphoid neoplasms (LNs) and its subtypes in Spain in the period 2002-2013 using data from the Spanish Network of Cancer Registries (REDECAN).

Materials and Methods

Data were extracted from 13 Spanish population-based cancer registries. LNs incident cases were codified using the International Classification of Diseases for Oncology, third edition (ICD-O-3) and grouped according to the WHO 2008 classification. Age-standardized incidence rates to the 2013 European standard population (ASIRe) were obtained. Poisson regression models were used to analyze trends in incidence rates and estimate the annual percentage change (APC) for each subtype. The number of cases in Spain for 2023 was estimated by applying the estimated age-specific rates for the year 2023 to the 2023 Spanish population. Observed survival (OS) was estimated by the Kaplan-Meier method and net survival (NS) by the Pohar-Perme method. Sex- and age-specific estimates of 5-year NS were calculated, as well as its changes according to two periods of diagnosis (2002-2007 and 2008-2013).

Results

LNs accounted for 69% (n=39,156) of all hematological malignancies (n=56,751) diagnosed during the period of study. Median age at diagnosis was 67 years (interquartile range (IQR) = 52-77). The overall ASIRe was 34.23 (95% confidence interval (CI): 33.89, 34.57) and showed a marked male predominance in almost all subtypes (global sex ratio = 1.45). During the study period, incidence trends of LNs remained stable (APC: 0.3; 95% CI: -0.1, 0.6), nevertheless some subtypes showed statistically significant variations, such as LNs NOS category (APC: -5.6; 95% CI: -6.8, -4.3). Around 17,926 new cases of LNs will be diagnosed in 2023 in Spain. Survival rates differed considerably across age-groups, while they were similar between men and women. Five- year NS was 62.81% (95% CI: 62.1, 63.52) for all LNs, and varied widely across LNs subtypes, ranging from 39.21% to 90.25%. NS for all LNs improved from the first period of diagnosis to the second one, being 61.57% (95% CI: 60.56, 62.61) in 2002-2007 and 64.17% (95% CI: 63.29, 65.07) in 2008-2013.

Conclusions

This study presents the first complete and extensive population-based analysis of LNs incidence and survival in Spain. These population-based data provide relevant information to better understand the epidemiology of LNs in Southern Europe and it features some useful points for public health authorities and clinicians. However, additional improvements regarding the registration of these hematological neoplasms can be implemented.

Mantle cell lymphoma in 2022-A comprehensive update on molecular pathogenesis, risk stratification, clinical approach, and current and novel treatments

The field of mantle cell lymphoma (MCL) has witnessed remarkable progress due to relentless advances in molecular pathogenesis, prognostication, and newer treatments. MCL consists of a spectrum of clinical subtypes. Rarely, atypical cyclin D1-negative MCL and in situ MCL neoplasia are identified. Prognostication of MCL is further refined by identifying somatic mutations (such as TP53, NSD2, KMT2D), methylation status, chromatin organization pattern, SOX-11 expression, minimal residual disease (MRD), and genomic clusters. Lymphoid tissue microenvironment studies demonstrated the role of B-cell receptor signaling, nuclear factor kappa B (NF-kB), colony-stimulating factor (CSF)-1, the CD70-SOX-11 axis. Molecular mechanism of resistance, mutation dynamics, and pathogenic pathways (B-cell receptor (BCR), oxidative phosphorylation, and MYC) were identified in mediating resistance to various treatments (bruton tyrosine kinase (BTK) inhibitors [ibrutinib, acalabrutinib]. Treatment options range from conventional chemoimmunotherapy and stem cell transplantation (SCT) to targeted therapies against BTK (covalent and noncovalent), Bcl2, ROR1, cellular therapy such as anti-CD19 chimeric antigen receptor therapy (CAR-T), and most recently bispecific antibodies against CD19 and CD20. MCL patients frequently relapse. Complex pathogenesis and the management of patients with progression after treatment with BTK/Bcl2 inhibitors and CAR-T (triple-resistant MCL) remain a challenge. Next-generation clinical trials incorporating newer agents and concurrent translational and molecular investigations are ongoing.

Epidemiology of Non-Hodgkin's Lymphoma

Non-Hodgins’s lymphoma (NHL) is the most common hematological malignancy worldwide, accounting for nearly 3% of cancer diagnoses and deaths. NHL is the seventh most prevalent cancer and has the sixth highest mortality among cancers in the US. NHL accounts for 4% of US cancer diagnoses, and incidence has increased 168% since 1975 (while survival has improved 158%). NHL is more common among men, those >65 years old, and those with autoimmune disease or a family history of hematological malignancies. NHL is a heterogenous disease, with each subtype associated with different risk factors. Marginal zone lymphoma (MZL) is strongly associated with Sjogren’s syndrome (SS) and Hashimoto’s thyroiditis, while peripheral T-cell lymphoma (PTCL) is most associated with celiac disease. Occupational exposures among farm workers or painters increases the risk of most of the common subtypes. Prior radiation treatment, obesity, and smoking are most highly associated with diffuse large B-cell lymphoma (DLBCL), while breast implants have been rarely associated with anaplastic large cell lymphoma (ALCL). Infection with Epstein–Barr Virus (EBV) is strongly associated with endemic Burkitts lymphoma. HIV and human herpes virus 8 (HHV-8), is predisposed to several subtypes of DLBCL, and human T-cell lymphoma virus (HTLV-1) is a causative agent of T-cell lymphomas. Obesity and vitamin D deficiency worsen NHL survival. Atopic diseases and alcohol consumption seem to be protective against NHL.

Germline variants of DNA repair genes in early onset mantle cell lymphoma

Although somatic mutations of DNA repair genes are frequent in mantle cell lymphoma (MCL), our understanding of their germline defects is limited. In a Chinese family with maternal Lynch syndrome and paternal B cell non-Hodgkin lymphoma, one sibling developed both Lynch syndrome and MCL. Lynch syndrome is caused by heterozygous mutations in mismatch repair (MMR) genes. To understand the genetic predispositions in the family, we performed exome sequencing and analyses of affected individuals and their tumor samples. A novel germline indel, MLH1 Gly101fsX1, was identified as the cause of Lynch syndrome, and unstable microsatellite loci and mutational signatures as evidence of defective MMR were revealed in the MCL sample. Furthermore, we included additional 15 MCL patients with early onset, and found by exome sequencing that 11 patients carried heterozygous germline variants of 20 DNA repair genes, including MSH2 in MMR. In the MCL with MSH2 Arg359fsX16, unstable microsatellite loci and defective MMR signatures were also found. In addition, five patients also had heterozygous germline variants of genes involved in B cell functions. Thus, our study found germline variants of genes in single-strand break repair, double-strand break repair, and Fanconi anemia pathway in early onset MCL; and for the first time we identified germline defects of MMR in two MCLs.

Linking Environmental Exposures to Molecular Pathogenesis in Non-Hodgkin Lymphoma Subtypes

Non-Hodgkin lymphoma comprises a heterogeneous group of hematologic malignancies, with about 60 subtypes that arise via various pathogenetic mechanisms. Although establishing etiology for specific NHL subtypes has been historically difficult given their relative rarity, environmental exposures have been repeatedly implicated as risk factors across many subtypes. Large-scale epidemiologic investigations have pinpointed chemical exposures in particular, but causality has not been established, and the exact biologic mechanisms underpinning these associations are unclear. Here we review chemical exposures that have been associated with development of NHL subtypes and discuss their biologic plausibility based on current research.

What Is Responsible for Heterogeneity in Mantle Cell Lymphoma Biology and Outcomes?

Mantle cell lymphoma, despite its common derivation from a t(11;14) error that occurs in a naïve B-cell leading to overexpression of cyclin D1 protein, is characterized by substantial heterogeneity in biology and clinical outcome. Unlike other non-Hodgkin lymphoma types, it is more common in men. Clinical presentation patterns vary from nodal to splenomegaly with leukemia to gastrointestinal involvement. Biological variability is linked to tumor cell proliferation. Increased monocyte/macrophages and their associated proinflammatory cytokines are associated with inferior outcomes. These clues mandate that new treatments should target signal pathways that contribute to these adverse outcomes.

Current status and perspectives regarding the association between allergic disorders and cancer

While activation of immune system may lead to a lower risk of some diseases, it has been shown that a history of atopic allergic disorders such as asthma, hay fever, eczema, and food allergies could be related to several types of cancer. However, the evidence is not entirely conclusive. Two proposals suggest a possible mechanism for the association between allergic disorders and cancers: immune surveillance and the antigenic stimulation. The association of allergy and cancer may vary by cancer site and the type of exposure. The aim of current review was to summarize the current knowledge of the association between allergic diseases and the risk of cancers with particular emphasis on case-controls and cohort studies to estimate the cancer risk associated with allergy.

TCL1 as a hub protein associated with the PI3K/AKT signaling pathway in diffuse large B-cell lymphoma based on proteomics methods

This study aimed to investigate the hub protein related to the phosphatidylinositol-3-kinase (PI3K)/protein kinase B (AKT) signaling pathway in diffuse large B-cell lymphoma (DLBCL). We used proteomics methods (iTRAQ) to explore the differentially expressed proteins in the non-germinal center B-cell -like (non-GCB) DLBCL in our previous study. In this study, a total of 137 formalin-fixed paraffin-embedded DLBCL tissue samples were analyzed via immunohistochemistry to verify the expression of TCL1, AKT1 + 2+3, IKKβ and to determine the differentially expressed proteins associated with the PI3K/AKT signaling pathway. Spearman correlation was used to analyze the relationship between these proteins, and survival analysis was used to investigate their effects on prognosis. Immunohistochemistry analysis indicated that TCL1, AKT1 + 2+3, and IKKβ were highly positively expressed in DLBCL. Results showed that the expression of TCL1 was related to ethnicity (p = 0.022), primary site (p = 0.045), Ann Arbor stage (p = 0.037), the International Prognostic Index (p = 0.005), β2-microglobulin (p = 0.030), BCL2 expression (p < 0.001), and Ki-67 expression (p = 0.008). A positive correlation was found between TCL1 and AKT1 + 2+3 (p < 0.001; r = 0.475). A positive correlation was also found between AKT1 + 2+3 and IKKβ (p < 0.001; r = 0.342). In survival analysis, anemia, non-treatment with R‑CHOP, positive TCL1 expression, and Ki-67 expression≥50% independently predicted short progression-free survival and overall survival in the total cohort (p < 0.05). Thus, TCL1 as a hub protein is associated with the PI3K/AKT signaling pathway in DLBCL. TCL1 expression indicated a poor prognosis in patients with DLBCL. With further studies, TCL1 may be established as a reliable prognostic biomarker and potential immunotherapeutic target for improving therapeutic efficacy for DLBCL in the future.

Priorities for Rural Lymphoma Survivors: A Qualitative Study

BACKGROUND

We gathered rural patient perspectives on lymphoma care and unmet needs throughout the treatment course to better understand their attitudes toward treatment and their barriers to participating in clinical research studies.

PATIENTS AND METHODS

We conducted 12 individual semi-structured telephone interviews in the spring of 2018 with lymphoma survivors from rural counties in Georgia. Patients were identified by a residential address in counties classified as rural according to the Rural-Urban Commuting Areas codes. Participants were recruited from regional patient education conferences and from current research participants at a university research hospital in Georgia. The interviews were recorded and transcribed verbatim. Thematic analysis and MAXQDA, version 18.0.8, were used to facilitate a constant comparative coding process during theme development.

RESULTS

The greatest barrier to care was the travel distance. The participants described difficulty navigating between local clinics and larger cancer centers. The lack of communication between the local and specialized clinics complicated the process, and participants had difficulty contacting or seeking advice from the team at the larger cancer centers. Seeking treatment from specialized clinics farther away introduced additional barriers. Most participants agreed that the use of technology was important for improved communication. Participants described lymphoma etiology, subtype-specific studies, alternative therapies, and quality of life as key research priorities.

CONCLUSION

These findings suggest that targeted research and interventions are necessary to address the specific needs of rural patients with and survivors of lymphoma. To address the disparity in health outcomes within rural populations, healthcare professionals and investigators can use these data to engage rural patients in treatment decision-making and research planning.

Mantle cell lymphoma: 2019 update on the diagnosis, pathogenesis, prognostication, and management

Unprecedented advances in our understanding of the pathobiology, prognostication, and therapeutic options in mantle cell lymphoma (MCL) have taken place in the last few years. Heterogeneity in the clinical course of MCL-indolent vs aggressive-is further delineated by a correlation with the mutational status of the variable region of immunoglobulin heavy chain, methylation status, and SOX-11 expression. Cyclin-D1 negative MCL, in situ MCL neoplasia, and impact of the karyotype on prognosis are distinguished. Apart from Ki-67% and morphology pattern (classic vs blastoid/pleomorphic), the proliferation gene signature has helped to further refine prognostication. Studies focusing on mutational dynamics and clonal evolution on Bruton's tyrosine kinase (BTK) inhibitors (ibrutinib, acalabrutinib) and/or Bcl2 antagonists (venetoclax) have further clarified the prognostic impact of somatic mutations in TP53, BIRC3, CDKN2A, MAP3K14, NOTCH2, NSD2, and SMARCA4 genes. In therapy, long-term follow-up on chemo-immunotherapy studies has demonstrated durable remissions in some patients; however, long-term toxicities, especially from second cancers, are a serious concern with chemotherapy. The therapeutic options in MCL are constantly evolving, with dramatic responses from nonchemotherapeutic agents (ibrutinib, acalabrutinib, and venetoclax). Chimeric antigen receptor therapy and combinations of nonchemotherapeutic agents are actively being studied and our focus is shifting toward making the treatment of MCL chemotherapy-free. Still, MCL remains incurable. The following aspects of MCL continue to pose a challenge: disease transformation, role of the cytokine-microenvironmental milieu, incorporation of positron emission tomography-computerized tomography imaging, minimal residual disease in the prognosis, circulating tumor DNA testing for clonal evolution, predicting resistance to BTK inhibitors, and optimal management of patients who progress on BTK/Bcl2 inhibitors. Next-generation clinical trials should incorporate nonchemotherapeutic agents and personalize the treatment based upon the genomic profile of individual patient. Recent advances in the field of MCL are reviewed.

Vitamin D status and risk of non-Hodgkin lymphoma: An updated meta-analysis

Purpose

This meta-analysis aimed to extensively investigate the association between various measures of vitamin D status and non-Hodgkin lymphoma (NHL) and its subtypes.

Methods

We searched MEDLINE (PubMed), Embase, and the Cochrane Library in February 2018. Two authors independently reviewed and selected articles based on predetermined criteria.

Results

A total of 30 studies with 56,458 NHL cases were finally selected, with 24, 9, and 3 studies on sunlight/ultraviolet radiation (UVR) exposure, dietary intake, and serum/plasma 25-hydroxyvitamin D levels, respectively. Significant protective effects of overall sunlight/UVR exposure on NHL and subtypes were observed, with summary relative risks (RRs) ranging from 0.67–0.80 (RR for NHL = 0.80; 95% confidence interval [CI]: 0.71–0.90) among subjects with high exposure compared to those with low exposure. The results were consistent with various classifications of sunlight/UVR exposure. In contrast, when exposure measures of dietary vitamin D intake (RR for NHL = 1.03; 95% CI: 0.90–1.19) and serum/plasma 25-hydroxyvitamin D levels (RR for NHL = 0.97; 95% CI: 0.82–1.15) were used, risk estimates were inconsistent or non-significant for NHL and the subtypes.

Conclusion

While risk estimates varied by different measures of vitamin D status, a protective effect of sunlight/UVR exposure on NHL incidence was verified, across most of the tested subtypes as well as exposure categories.

Population-based incidence of lymphoid neoplasms: Twenty years of epidemiological data in the Girona province, Spain

BACKGROUND

The aim of this study was to describe incidence patterns of lymphoid neoplasms in the Girona province (Spain) (1996-2015), and to predict the number of cases in Spain during 2020.

METHODS

Data were extracted from the Girona cancer registry. Incident cases were classified using the ICD-O-3, third revision, and grouped according to the WHO 2008 classification scheme. Age-adjusted incidence rates to the European standard population (ASRE) were estimated and incidence trends were modeled using Joinpoint.

RESULTS

4367 lymphoid neoplasms were diagnosed in the Girona province. The ASRE for overall lymphoma was 37.1 (95% CI: 36.0; 38.2), with a marked male predominance in almost all subtypes. During 1996-2015, incidence trends remained stable for broader lymphoma categories. According to our predictions, 17,950 new cases of LNs will be diagnosed in Spain in 2020.

CONCLUSIONS

This 'real-world' data will provide valuable information to better inform etiological hypotheses and plan future health-care services.

New and emerging Bruton tyrosine kinase inhibitors for treating mantle cell lymphoma - where do they fit in?

INTRODUCTION

Despite recent prognostic improvements, mantle cell lymphoma (MCL) remains incurable. Bruton tyrosine kinase (BTK) is a key receptor in B-cell tumorigenesis, and the benefits of the first BTK inhibitor, ibrutinib, are becoming clear in MCL. However, off-target activities, which contribute to ibrutinib-related adverse events, suggest potential for further improvement of this drug class. Areas covered: The authors systematically interrogated ClinicalTrials.gov for trials containing keywords for BTK and MCL. Published literature for new and emerging BTK inhibitors being investigated in MCL was then identified (PubMed and Embase), summarized, and placed in the context of treatment guidelines. Expert commentary: Reduced off-target effects of new and emerging covalent, irreversible BTK inhibitors under investigation in patients with MCL offer the potential of improved safety compared with ibrutinib. Efficacy may also be favorable based on trial data for acalabrutinib, which has just been approved in the USA as second-line therapy for MCL. The role of BTK inhibitors in treating MCL will evolve substantially over the coming years as results from a number of trials become available, particularly in relation to potential upfront use and possible synergy with other targeted therapies such as B-cell lymphoma 2, phosphoinositide 3-kinase and checkpoint inhibitors.

Chronic lymphocytic leukemia and mantle cell lymphoma: crossroads of genetic and microenvironment interactions

Chronic lymphocytic leukemia (CLL) and mantle cell lymphoma (MCL) are 2 well-defined entities that diverge in their basic pathogenic mechanisms and clinical evolution but they share epidemiological characteristics, cells of origin, molecular alterations, and clinical features that differ from other lymphoid neoplasms. CLL and MCL are classically considered indolent and aggressive neoplasms, respectively. However, the clinical evolution of both tumors is very heterogeneous, with subsets of patients having stable disease for a long time whereas others require immediate intervention. Both CLL and MCL include 2 major molecular subtypes that seem to derive from antigen-experienced CD5⁺ B cells that retain a naive or memory-like epigenetic signature and carry a variable load of immunoglobulin heavy-chain variable region somatic mutations from truly unmutated to highly mutated, respectively. These 2 subtypes of tumors differ in their molecular pathways, genomic alterations, and clinical behavior, being more aggressive in naive-like than memory-like-derived tumors in both CLL and MCL. The pathogenesis of the 2 entities integrates the relevant influence of B-cell receptor signaling, tumor cell microenvironment interactions, genomic alterations, and epigenome modifications that configure the evolution of the tumors and offer new possibilities for therapeutic intervention. This review will focus on the similarities and differences of these 2 tumors based on recent studies that are enhancing the understanding of their pathogenesis and creating solid bases for new management strategies.

Mantle Cell Lymphoma: Is It Time for a New Treatment Paradigm?

Mantle cell lymphoma is a relatively rare subtype of lymphoma with a great deal of heterogeneity, both clinically and biologically. Since its recognition as a separate entity in the early 1990s though, consistent efforts have led to a significant improvement of overall survival, from a median overall survival of 2.5 years initially to 5-7 years currently. This decades-long and stepwise progress, summarized in the article, definitely accelerated recently, shedding light on a changing paradigm.

Mantle Cell Lymphoma: Contemporary Diagnostic and Treatment Perspectives in the Age of Personalized Medicine

Mantle cell lymphoma is a clinically heterogeneous disease occurring within a heterogeneous patient population, highlighting a need for personalized therapy to ensure optimal outcomes. It is therefore critical to understand the benefits and risks associated with both intensive and deintensified approaches. In the following review we provide a therapeutic roadmap to strategically guide treatment for newly diagnosed and relapsed/refractory patients highlighting pivotal and recently published results involving known and novel therapies.

Atopy and Specific Cancer Sites: a Review of Epidemiological Studies

Mounting evidence appears to link asthma and atopy to cancer susceptibility. This review presents and discusses published epidemiological studies on the association between site-specific cancers and atopy. PubMed was searched electronically for publications between 1995 and 2015, and cited references were researched manually. Quantitative studies relating to atopy, allergy, or asthma and cancer were identified and tabulated. Despite many exposure-related limitations, patterns in the studies were observed. Asthma, specifically, has been observed to be a risk factor for lung cancer. A protective effect of atopic diseases against pancreatic cancer has been shown consistently in case-control studies but not in cohort studies. Allergy of any type appears to be protective against glioma and adult acute lymphoblastic leukemia. Most studies on atopic diseases and non-Hodgkin lymphoma or colorectal cancer reported an inverse association. The other sites identified had varying and non-significant outcomes. Further research should be dedicated to carefully defined exposure assessments of "atopy" as well as the biological plausibility in the association between atopic diseases and cancer.

Non-Hodgkin lymphoma in the developing world: review of 4539 cases from the International Non-Hodgkin Lymphoma Classification Project

The distribution of non-Hodgkin lymphoma subtypes varies around the world, but a large systematic comparative study has never been done. In this study, we evaluated the clinical features and relative frequencies of non-Hodgkin lymphoma subtypes in five developing regions of the world and compared the findings to the developed world. Five expert hematopathologists classified 4848 consecutive cases of lymphoma from 26 centers in 24 countries using the World Health Organization classification, and 4539 (93.6%) were confirmed to be non-Hodgkin lymphoma, with a significantly greater number of males than females in the developing regions compared to the developed world (P<0.05). The median age at diagnosis was significantly lower for both low- and high-grade B-cell lymphoma in the developing regions. The developing regions had a significantly lower frequency of B-cell lymphoma (86.6%) and a higher frequency of T- and natural killer-cell lymphoma (13.4%) compared to the developed world (90.7% and 9.3%, respectively). Also, the developing regions had significantly more cases of high-grade B-cell lymphoma (59.6%) and fewer cases of low-grade B-cell lymphoma (22.7%) compared to the developed world (39.2% and 32.7%, respectively). Among the B-cell lymphomas, diffuse large B-cell lymphoma was the most common subtype (42.5%) in the developing regions. Burkitt lymphoma (2.2%), precursor B- and T-lymphoblastic leukemia/lymphoma (1.1% and 2.9%, respectively) and extranodal natural killer/T-cell lymphoma (2.2%) were also significantly increased in the developing regions. These findings suggest that differences in etiologic and host risk factors are likely responsible, and more detailed epidemiological studies are needed to better understand these differences.

Integrating understanding of epidemiology and genomics in B-cell non-Hodgkin lymphoma as a pathway to novel management strategies

Non-Hodgkin lymphomas include a biologically and clinically heterogeneous group of cancers distinguished by genetics, histology, and treatment outcomes. New discoveries regarding the genomic alterations and epidemiological exposures associated with these lymphomas have enhanced our understanding of factors that contribute to lymphomagenesis for specific subtypes. We explore the impact of normal B-cell biology engineered for recognizing a wide variety of antigens on the development of specific lymphoma subtypes, review lymphoma genetics, and examine the epidemiology of B-cell NHLs including recent investigations of risk factors for particular lymphoma subtypes based on large pooled analyses. Burkitt lymphoma, an aggressive form of B-cell NHL involving translocation of the MYC gene and an immunoglobulin gene has been associated with a history of eczema, hepatitis C, and occupation as a cleaner. Increased risk of diffuse large B-cell lymphoma has been associated with increased young adult body mass index, history of B-cell-activating autoimmune diseases, hepatitis C, and several single nucleotide variants involving the human leukocyte antigen (HLA) region of chromosome 6 and non-HLA loci near EXOC2, PVT1, MYC, and NCOA1. Tumor sequencing studies suggest that multiple pathways are involved in the development of DLBCL. Additional studies of epidemiological exposures, genome wide associations, and tumor sequencing in follicular, lymphoplasmacytic, marginal zone, and mantle cell lymphoma demonstrate overlapping areas of increased risk factors and unique factors for specific subtypes. Integrating these findings is important for constructing comprehensive models of NHL pathogenesis, which could yield novel targets for therapy and strategies for lymphoma prevention in certain populations.

The role of infectious agents, antibiotics, and antiviral therapy in the treatment of extranodal marginal zone lymphoma and other low-grade lymphomas

OPINION STATEMENT

There is strong evidence to corroborate the association with Helicobacter pylori (Hp) to gastric extranodal marginal zone lymphoma (ENMZL) and hepatitis C virus (HCV) to splenic/nodal marginal zone lymphoma. Koch's postulates generally hold for these two associations and eradication of the infectious agent is well supported. Hp eradication (HPE) is recommended as front-line therapy for early stage gastric ENMZL regardless of Hp status. Complete response (CR) rate for Hp-negative patients is not as high as for Hp-positive patients; however, the benign nature of HPE and high rates of salvage allow this strategy to be safe while sparing some Hp-negative patients from systemic therapy or radiation. Similarly for HCV-seropositive patients, treatment with antivirals should be strongly considered as first-line for those who do not require immediate cytoreductive therapy or at some point even after completing chemoimmunotherapy. The controversy regarding the role for antibiotics is greatest for primary ocular adnexal lymphoma (POAL). Considering the low incidence of Chlamydia psittaci (Cp) infection with OAL and the challenges to reliably identifying Cp, we typically do not consider doxycycline in POAL treatment. Involved-field radiotherapy (IFRT) remains the treatment of choice for most with unilateral POAL. However, if reliable detection of Cp is available and Cp is identified, patients with unilateral low tumor stage POAL who do not require immediate radiotherapy could be considered for doxycycline as front-line treatment. Other infectious associations to indolent lymphomas have been made, including Borrelia borgdorferi (Bb) in cutaneous lymphoma and Campylobacter in immunoproliferative small intestinal disease (IPSID), but these associations are not as strong and primary treatment targeting the infectious agents is not recommended.

To Each Its Own: Linking the Biology and Epidemiology of NHL Subtypes

Non-Hodgkin lymphoma (NHL) constitutes a diverse group of more than 40 subtypes, each characterized by distinct biologic and clinical features. Until recently, pinpointing genetic and epidemiologic risk factors for individual subtypes has been limited by the relative rarity of each. However, several large pooled case-control studies have provided sufficient statistical power for detecting etiologic differences and commonalities between subtypes and thus yield new insight into their unique epidemiologic backgrounds. Here, we review the subtype-specific medical, lifestyle, and biologic components identified in these studies, which suggest that a complex interplay between host genetics, autoimmune disorders, modifiable risk factors, and occupation contributes to lymphomagenesis.

Specific Inhibition of β-Catenin in Jeko-1 Mantle Cell Lymphoma Cell Line Decreases Proliferation and Induces Apoptosis

BACKGROUND

The canonical Wnt signaling pathway has been considered as a potent oncogenic signaling in the initiation and progression of hematological malignancies. As a key regulator of the Wnt signaling pathway, the role of β-catenin in mantle cell lymphoma (MCL) pathogenesis and progression was investigated in this study.

MATERIAL AND METHODS

A total of 30 MCL samples were collected from patients and were examined for the expression of β-catenin and p-GSK3β using immunohistochemical (IHC) staining. Further in vitro studies employed MTT and Western blot assays detecting proliferation and apoptosis-related proteins in MCL cell line Jeko-1, which were transfected with β-catenin shRNA or specific inhibitor XAV939.

RESULTS

Expression of β-catenin and phosphorylated glycogen synthase kinase-3 beta (p-GSK3β) in MCL was significantly higher than those in controlled samples. In vitro studies indicated that β-catenin knockdown significantly inhibited cell proliferation and induced apoptosis in Jeko-1 cells. Furthermore, XAV939 induced apoptosis and growth arrest in Jeko-1 cells. Both inhibitory agents increased Bax and caspase 3 proteins, and decreased Bcl-2, c-Myc, and Cyclin D1 proteins.

CONCLUSIONS

The specific inhibition of β-catenin induces apoptosis and growth arrest, making it a potential therapeutic target against MCL.

Etiologic heterogeneity among non-Hodgkin lymphoma subtypes: the InterLymph Non-Hodgkin Lymphoma Subtypes Project

BACKGROUND

Non-Hodgkin lymphoma (NHL) comprises biologically and clinically heterogeneous subtypes. Previously, study size has limited the ability to compare and contrast the risk factor profiles among these heterogeneous subtypes.

METHODS

We pooled individual-level data from 17 471 NHL cases and 23 096 controls in 20 case-control studies from the International Lymphoma Epidemiology Consortium (InterLymph). We estimated the associations, measured as odds ratios, between each of 11 NHL subtypes and self-reported medical history, family history of hematologic malignancy, lifestyle factors, and occupation. We then assessed the heterogeneity of associations by evaluating the variability (Q value) of the estimated odds ratios for a given exposure among subtypes. Finally, we organized the subtypes into a hierarchical tree to identify groups that had similar risk factor profiles. Statistical significance of tree partitions was estimated by permutation-based P values (P NODE).

RESULTS

Risks differed statistically significantly among NHL subtypes for medical history factors (autoimmune diseases, hepatitis C virus seropositivity, eczema, and blood transfusion), family history of leukemia and multiple myeloma, alcohol consumption, cigarette smoking, and certain occupations, whereas generally homogeneous risks among subtypes were observed for family history of NHL, recreational sun exposure, hay fever, allergy, and socioeconomic status. Overall, the greatest difference in risk factors occurred between T-cell and B-cell lymphomas (P NODE < 1.0×10(-4)), with increased risks generally restricted to T-cell lymphomas for eczema, T-cell-activating autoimmune diseases, family history of multiple myeloma, and occupation as a painter. We further observed substantial heterogeneity among B-cell lymphomas (P NODE < 1.0×10(-4)). Increased risks for B-cell-activating autoimmune disease and hepatitis C virus seropositivity and decreased risks for alcohol consumption and occupation as a teacher generally were restricted to marginal zone lymphoma, Burkitt/Burkitt-like lymphoma/leukemia, diffuse large B-cell lymphoma, and/or lymphoplasmacytic lymphoma/Waldenström macroglobulinemia.

CONCLUSIONS

Using a novel approach to investigate etiologic heterogeneity among NHL subtypes, we identified risk factors that were common among subtypes as well as risk factors that appeared to be distinct among individual or a few subtypes, suggesting both subtype-specific and shared underlying mechanisms. Further research is needed to test putative mechanisms, investigate other risk factors (eg, other infections, environmental exposures, and diet), and evaluate potential joint effects with genetic susceptibility.

Rationale and Design of the International Lymphoma Epidemiology Consortium (InterLymph) Non-Hodgkin Lymphoma Subtypes Project

BACKGROUND

Non-Hodgkin lymphoma (NHL), the most common hematologic malignancy, consists of numerous subtypes. The etiology of NHL is incompletely understood, and increasing evidence suggests that risk factors may vary by NHL subtype. However, small numbers of cases have made investigation of subtype-specific risks challenging. The International Lymphoma Epidemiology Consortium therefore undertook the NHL Subtypes Project, an international collaborative effort to investigate the etiologies of NHL subtypes. This article describes in detail the project rationale and design.

METHODS

We pooled individual-level data from 20 case-control studies (17471 NHL cases, 23096 controls) from North America, Europe, and Australia. Centralized data harmonization and analysis ensured standardized definitions and approaches, with rigorous quality control.

RESULTS

The pooled study population included 11 specified NHL subtypes with more than 100 cases: diffuse large B-cell lymphoma (N = 4667), follicular lymphoma (N = 3530), chronic lymphocytic leukemia/small lymphocytic lymphoma (N = 2440), marginal zone lymphoma (N = 1052), peripheral T-cell lymphoma (N = 584), mantle cell lymphoma (N = 557), lymphoplasmacytic lymphoma/Waldenström macroglobulinemia (N = 374), mycosis fungoides/Sézary syndrome (N = 324), Burkitt/Burkitt-like lymphoma/leukemia (N = 295), hairy cell leukemia (N = 154), and acute lymphoblastic leukemia/lymphoma (N = 152). Associations with medical history, family history, lifestyle factors, and occupation for each of these 11 subtypes are presented in separate articles in this issue, with a final article quantitatively comparing risk factor patterns among subtypes.

CONCLUSIONS

The International Lymphoma Epidemiology Consortium NHL Subtypes Project provides the largest and most comprehensive investigation of potential risk factors for a broad range of common and rare NHL subtypes to date. The analyses contribute to our understanding of the multifactorial nature of NHL subtype etiologies, motivate hypothesis-driven prospective investigations, provide clues for prevention, and exemplify the benefits of international consortial collaboration in cancer epidemiology.

New insights into the epidemiology of non-Hodgkin lymphoma and implications for therapy

Non-Hodgkin lymphoma (NHL) comprises numerous biologically and clinically heterogeneous subtypes, with limited data examining the risk factors for these distinct disease entities. Many limitations exist when studying lymphoma epidemiology; therefore, until recently, little was known regarding the etiology of NHL subtypes. This review highlights the results of recent pooled analyses examining the risk factors for NHL subtypes. We outline the heterogeneity and commonality among the risk factors for NHL subtypes, with proposed subtype-specific as well as shared etiologic mechanisms. In addition, we describe how the study of lymphoma epidemiology may translate into prevention or therapeutic targeting as we continue to explore the complexities of lifestyle and genetic factors that impact lymphomagenesis.