Risk of familial classical Hodgkin lymphoma by relationship, histology, age, and sex: a joint study from five Nordic countries

Elevated serum TARC levels precede classic Hodgkin lymphoma diagnosis by several years

Tumor cells in classic Hodgkin lymphoma produce high quantities of the thymus- and activation-related chemokine (TARC). We measured TARC levels in prediagnostic serum samples and found strikingly increased values in the vast majority of patients, as early as 6 years before diagnosis.

Classic Hodgkin lymphoma in young people

Classic Hodgkin lymphoma (CHL) is a unique form of lymphoid cancer featuring a heterogeneous tumor microenvironment and a relative paucity of malignant Hodgkin and Reed-Sternberg (HRS) cells with characteristic phenotype. Younger individuals (children, adolescents and young adults) are affected as often as the elderly, producing a peculiar bimodal age-incidence profile that has generated immense interest in this disease and its origins. Decades of epidemiological investigations have documented the populations most susceptible and identified multiple risk factors that can be broadly categorized as either biological or environmental in nature. Most risk factors result in overt immunodeficiency or confer more subtle alterations to baseline health, physiology or immune function. Epstein Barr virus, however, is both a risk factor and well-established driver of lymphomagenesis in a significant subset of cases. Epigenetic changes, along with the accumulation of somatic driver mutations and cytogenetic abnormalities are required for the malignant transformation of germinal center-experienced HRS cell precursors. Chromosomal instability and the influence of endogenous mutational processes are critical in this regard, by impacting genes involved in key signaling pathways that promote the survival and proliferation of HRS cells and their escape from immune destruction. Here we review the principal features, known risk factors and lymphomagenic mechanisms relevant to newly diagnosed CHL, with an emphasis on those most applicable to young people.

Composite Lymphoma's Ability to Adapt and Change Through Plasticity: A Case Report and Literature Review

Composite/synchronous lymphoma is an uncommon condition that presents a challenge in histopathological diagnosis due to the simultaneous appearance of two or more lymphomas, including instances where they are intermixed within the same location. Performing a core needle tissue biopsy adds a challenge for pathologists when trying to diagnose a condition that requires excisional tissue for a thorough evaluation. This report highlights a distinctive instance of composite lymphoma in which classical Hodgkin lymphoma (cHL) is combined with diffuse large B-cell lymphoma (DLBCL). All pertinent information including clinical, histopathological, and immunohistochemical data for each of these composite lymphomas is provided. In addition, we conducted a literature review of the published data. The findings from these data further support the theory of a shared clonal origin and transdifferentiation occurrence in the process of lymphoma development.

Classical Hodgkin Lymphoma: From Past to Future-A Comprehensive Review of Pathophysiology and Therapeutic Advances

Hodgkin lymphoma, a hematological malignancy of lymphoid origin that typically arises from germinal-center B cells, has an excellent overall prognosis. However, the treatment of patients who relapse or develop resistant disease still poses a substantial clinical and research challenge, even though current risk-adapted and response-based treatment techniques produce overall survival rates of over 95%. The appearance of late malignancies after the successful cure of primary or relapsed disease continues to be a major concern, mostly because of high survival rates. Particularly in pediatric HL patients, the chance of developing secondary leukemia is manifold compared to that in the general pediatric population, and the prognosis for patients with secondary leukemia is much worse than that for patients with other hematological malignancies. Therefore, it is crucial to develop clinically useful biomarkers to stratify patients according to their risk of late malignancies and determine which require intense treatment regimens to maintain the ideal balance between maximizing survival rates and avoiding late consequences. In this article, we review HL's epidemiology, risk factors, staging, molecular and genetic biomarkers, and treatments for children and adults, as well as treatment-related adverse events and the late development of secondary malignancies in patients with the disease.

Identification and Interpretation of eQTL and eGenes for Hodgkin Lymphoma Susceptibility

Genome-wide association studies (GWAS) have revealed approximately 100 genomic signals associated with Hodgkin lymphoma (HL); however, their target genes and underlying mechanisms causing HL susceptibility remain unclear. In this study, transcriptome-wide analysis of expression quantitative trait loci (eQTL) was conducted to identify target genes associated with HL GWAS signals. A mixed model, which explains polygenic regulatory effects by the genomic covariance among individuals, was implemented to discover expression genes (eGenes) using genotype data from 462 European/African individuals. Overall, 80 eGenes were identified to be associated with 20 HL GWAS signals. Enrichment analysis identified apoptosis, immune responses, and cytoskeletal processes as functions of these eGenes. The eGene of rs27524 encodes ERAP1 that can cleave peptides attached to human leukocyte antigen in immune responses; its minor allele may help Reed-Sternberg cells to escape the immune response. The eGene of rs7745098 encodes ALDH8A1 that can oxidize the precursor of acetyl-CoA for the production of ATP; its minor allele may increase oxidization activity to evade apoptosis of pre-apoptotic germinal center B cells. Thus, these minor alleles may be genetic risk factors for HL susceptibility. Experimental studies on genetic risk factors are needed to elucidate the underlying mechanisms of HL susceptibility and improve the accuracy of precision oncology.

Discovery of novel predisposing coding and noncoding variants in familial Hodgkin lymphoma

Familial aggregation of Hodgkin lymphoma (HL) has been demonstrated in large population studies, pointing to genetic predisposition to this hematological malignancy. To understand the genetic variants associated with the development of HL, we performed whole genome sequencing on 234 individuals with and without HL from 36 pedigrees that had 2 or more first-degree relatives with HL. Our pedigree selection criteria also required at least 1 affected individual aged <21 years, with the median age at diagnosis of 21.98 years (3-55 years). Family-based segregation analysis was performed for the identification of coding and noncoding variants using linkage and filtering approaches. Using our tiered variant prioritization algorithm, we identified 44 HL-risk variants in 28 pedigrees, of which 33 are coding and 11 are noncoding. The top 4 recurrent risk variants are a coding variant in KDR (rs56302315), a 5' untranslated region variant in KLHDC8B (rs387906223), a noncoding variant in an intron of PAX5 (rs147081110), and another noncoding variant in an intron of GATA3 (rs3824666). A newly identified splice variant in KDR (c.3849-2A>C) was observed for 1 pedigree, and high-confidence stop-gain variants affecting IRF7 (p.W238∗) and EEF2KMT (p.K116∗) were also observed. Multiple truncating variants in POLR1E were found in 3 independent pedigrees as well. Whereas KDR and KLHDC8B have previously been reported, PAX5, GATA3, IRF7, EEF2KMT, and POLR1E represent novel observations. Although there may be environmental factors influencing lymphomagenesis, we observed segregation of candidate germline variants likely to predispose HL in most of the pedigrees studied.

Diagnosis and management of Hodgkin lymphoma in children, adolescents, and young adults

Advances in the management of Hodgkin lymphoma in children, adolescents and young adult have resulted in survival outcomes exceeding 90%. The risk of late toxicity, however, remains a significant concern for survivors of HL and the focus of modern trials have been to advance cure rates while reducing long term toxicity. This has been accomplished through response-adapted treatment approaches and the incorporation of novel agents, many of which target the unique interaction between the Hodgkin and Reed Sternberg cells and the tumor microenvironment. In addition, an improved understanding of prognostic markers, risk stratification, and the biology of this entity in children and AYAs may allow us to further tailor therapy. This review focuses on the current management of HL in the upfront and relapsed settings, recent advances in novel agents that target HL and the tumor microenvironment, and promising prognostic markers that may help guide the future management of HL.

Older patients with Hodgkin Lymphoma: Walking the tightrope of efficacy and toxicity

Since its initial description, classical Hodgkin lymphoma (cHL) portends a greatly improved prognosis and the goal of treatment in most patients is cure with minimisation of toxicity from treatment. Outcomes in older patients (>60 years old) lag behind those of their younger counterparts however, and cure remains achievable mostly for those who can tolerate full doses of conventional chemotherapy. This review addresses the difference in biology between younger and older patients with cHL and examines the impact of frailty and comorbidities on outcomes. The toxicities of conventional chemotherapy in anthracycline-fit and -unfit patients are examined, with a particular focus on pulmonary toxicity associated with bleomycin in older patients. New advances are discussed, including the possibility of using more targeted therapies such as the anti-CD30 antibody brentuximab vedotin (BV) and checkpoint inhibitors as a method of reducing dependency on conventional chemotherapy for those less well able to tolerate it. Treatment of older patients with cHL remains an area of unmet need in hematological research, and efforts to rectify this knowledge gap should continue.

Genetic lesions and targeted therapy in Hodgkin lymphoma

Hodgkin lymphoma is a special type of lymphoma in which tumor cells frequently undergo multiple genetic lesions that are associated with accompanying pathway abnormalities. These pathway abnormalities are dominated by active signaling pathways, such as the JAK-STAT (Janus kinase-signal transducer and activator of transcription) pathway and the NFκB (nuclear factor kappa-B) pathway, which usually result in hyperactive survival signaling. Targeted therapies often play an important role in hematologic malignancies, such as CAR-T therapy (chimeric antigen receptor T-cell immunotherapy) targeting CD19 and CD22 in diffuse large B-cell lymphoma, while in Hodgkin lymphoma, the main targets of targeted therapies are CD30 molecules and PD1 molecules. Drugs targeting other molecules are also under investigation. This review summarizes the actionable genetic lesions, current treatment options, clinical trials for Hodgkin lymphoma and the potential value of those genetic lesions in clinical applications.

An update on molecular features and therapeutic perspectives of pediatric classical Hodgkin Lymphoma. What the clinician needs to know?

Our understanding of Hodgkin lymphoma (HL) molecular biology has been radically transformed over recent years due to the advent and the spreading of the new generation sequencing approaches. These advances offer new insights about genetic predisposition to HL in children and are currently being translated into promising and more selective drugs (brentuximab and checkpoint inhibitors) offering the perspective to reduce treatment-related toxicity. Thus, as more than 90% of pediatric patients are cured after the first line treatment, a major emphasis is placed on survivorship by reducing treatment intensity, in particular, the use of radiotherapy and chemotherapy associated with long-term toxicities. The purposes of this review are to summarize the recent advances performed in the field of molecular biology of HL, in particular the promising development of liquid biopsies. We also provide an update review of immunodeficiencies associated to HL in children recently identified. Finally, we report the recent studies supporting the efficacy of new targeted therapeutics in adult and pediatric cHL (anti-CD30 and anti-PD1).

Plasticity in Classical Hodgkin Composite Lymphomas: A Systematic Review

The co-occurrence of several lymphomas in a patient defines composite/synchronous lymphoma. A common cellular origin has been reported for both contingents of such entities. In the present review, we aimed to gather the available data on composite lymphomas associating a classical Hodgkin lymphoma (cHL) with another lymphoma, to better understand the plasticity of mature B and T-cells. This review highlights that >70% of patients with a composite lymphoma are ≥55 years old, with a male predominance. The most reported associations are cHL with follicular lymphoma or diffuse large B-cell lymphoma, with over 130 cases reported. The cHL contingent is often of mixed cellularity type, with a more frequent focal/weak CD20 expression (30% to 55.6%) compared to de novo cHL, suggesting a particular pathophysiology. Moreover, Hodgkin cells may express specific markers of the associated lymphoma (e.g., BCL2/BCL6 for follicular lymphoma and Cyclin D1 for mantle cell lymphoma), sometimes combined with common BCL2/BCL6 or CCND1 rearrangements, respectively. In addition, both contingents may share similar IgH/IgK rearrangements and identical pathogenic variants, reinforcing the hypothesis of a common clonal origin. Finally, cHL appears to be endowed with a greater plasticity than previously thought, supporting a common clonal origin and a transdifferentiation process during lymphomagenesis of composite lymphomas.

Global patterns of Hodgkin lymphoma incidence and mortality in 2020 and a prediction of the future burden in 2040

Our study examines global patterns of Hodgkin lymphoma (HL) in 2020 and predicts the future incidence and mortality burden in 2040 using IARC's GLOBOCAN estimates of the number of new cases and deaths of HL in 185 countries. A total of 83 000 new cases of HL and 23 000 deaths from HL were estimated in 2020. In general, incidence and mortality rates were consistently higher in males (50% more cases and deaths than females) across world regions and countries. Incidence rates varied markedly by world region, at least 10-fold in both sexes, with the highest incidence rates observed in Southern Europe. Mortality exhibited an inverse pattern compared to incidence, with rates elevated in Western Asia and Northern Africa. The number of HL incident cases is predicted to rise to around 107 000 cases (a 30% increase) by 2040 due to demographic changes, assuming global rates in 2020 remains unchanged. The findings provide a baseline and impetus for developing strategies that aim to reduce the burden of HL in future decades.

Therapy-related myeloid neoplasms with different latencies: a detailed clinicopathologic analysis

Therapy-related myeloid neoplasm (t-MN) arising in patients with prior cytotoxic treatments is considered a distinct entity due to its unfavorable prognosis. Latencies between the initial cytotoxic therapy and the occurrence of t-MNs vary but usually fall between 1 and 10 years. t-MNs with unusually short or long latencies are not well characterized. It is unclear if they are biologically similar to the ones with ordinary latencies and should be kept in the t-MN entity. We compiled a cohort of t-MN cases including short (<1 year), ordinary (1-10 years), and extended (>10 years) latencies from two tertiary medical centers. Both the t-MNs with ordinary and extended latencies showed high likelihood of high-risk genetic abnormalities and demonstrated no significant survival differences. But the t-MNs with extended latencies were more likely associated with history of multiple cancers (p = 0.007) and were younger at the time of cytotoxic treatments (p < 0.001) when compared to the t-MNs with ordinary latencies. The t-MN with short latencies appears to be a very rare and highly heterogeneous group. In summary, the genetic composition appears similar in the t-MNs with ordinary and extended latencies. However, the association between the t-MN with extended latencies and history of multiple cancers raises a possibility that cancer predisposition may contribute to the accumulation of genetic abnormalities in these patients. Investigation into potential germline mutations in the t-MN patients with extended latencies may provide important information for related family members.

Familial Risk and Heritability of Hematologic Malignancies in the Nordic Twin Study of Cancer

Simple Summary

Hematologic malignancies account for 8–9% of all incident cancers. Both genetic and environmental risk factors contribute to cancer development, but it is unclear if there is shared heritability between hematologic malignancies. This study aimed to investigate familial predisposition to hematologic malignancies using the largest twin study of cancer in the world. We compared individual risk in the general population and the risk of cancer in one twin before some age given that the other twin had (another) cancer before that age. Furthermore, by analyzing information about whether the twins were identical or fraternal, we could estimate the relative importance of genetic and environmental influences on the risk for developing hematologic cancers. This study confirmed previous findings of familial predisposition to hematologic malignancies and provides novel evidence that familial predisposition decreases with increasing age. The latter points to the importance of taking age into account in the surveillance of hematological cancers.

Abstract

We aimed to explore the genetic and environmental contributions to variation in the risk of hematologic malignancies and characterize familial dependence within and across hematologic malignancies. The study base included 316,397 individual twins from the Nordic Twin Study of Cancer with a median of 41 years of follow-up: 88,618 (28%) of the twins were monozygotic, and 3459 hematologic malignancies were reported. We estimated the cumulative incidence by age, familial risk, and genetic and environmental variance components of hematologic malignancies accounting for competing risk of death. The lifetime risk of any hematologic malignancy was 2.5% (95% CI 2.4–2.6%), as in the background population. This risk was elevated to 4.5% (95% CI 3.1–6.5%) conditional on hematologic malignancy in a dizygotic co-twin and was even greater at 7.6% (95% CI 4.8–11.8%) if a monozygotic co-twin had a hematologic malignancy. Heritability of the liability to develop any hematologic malignancy was 24% (95% CI 14–33%). This estimate decreased across age, from approximately 55% at age 40 to about 20–25% after age 55, when it seems to stabilize. In this largest ever studied twin cohort with the longest follow-up, we found evidence for familial risk of hematologic malignancies. The discovery of decreasing familial predisposition with increasing age underscores the importance of cancer surveillance in families with hematological malignancies.

Familial aggregation of early-onset haematological malignancies

Population-based studies on familial aggregation of haematological malignancies (HM) have rarely focused specifically on early-onset HMs. We estimated standardized incidence ratios (SIR) and cumulative risks of relatives with Hodgkin lymphoma (HL), non-Hodgkin lymphomas (NHL), acute lymphoblastic leukaemia/lymphoma (ALL/LBL) and acute myeloid leukaemia (AML) when index persons and relatives were diagnosed with early-onset HM. A total of 8791 patients aged ≤40 years and diagnosed with primary HM in Finland from 1970 to 2012 were identified from the Finnish Cancer Registry and their 75 774 family members were retrieved from the population registry. SIRs for concordant HMs were elevated among first-degree relatives in all of the most common HMs of children and adolescents and young adults (AYA). The risk was highest among siblings with HL (SIR 9·09, 95% confidence interval 5·55-14·04) and AML (8·29, 1·00-29·96). HL also had the highest cumulative risk for siblings at ≤40 years of age (0·92% vs. 0·11% in the population). In conclusion, significantly elevated SIRs indicate a role of shared aetiological factors in some families, which should be noted in the clinical setting when caring for patients with early-onset HMs.

Risk of hematological malignancies in the families of patients treated for nodular lymphocyte-predominant Hodgkin lymphoma

BACKGROUND

Familial clustering of lymphoid and/or hematological malignancies (FHM) provides an opportunity to study the responsible genes. The data is limited in patients with lymphoid and hematological malignancies.

METHODS

The lymphoma database was used to identify patients seen in our institution from 1998 to 2019 with nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL). We studied FHM by collecting detailed history of any malignancy in the family (FM).

RESULTS

Two hundred NLPHL patients were identified. Contacting was not possible in 30 patients due to no response to the phone calls (22) and death [1]. 170/200 patients were interviewed; represented 167 families (3 patients with a family member with NLPHL). These 170 patients provided information about 8225 family members. These 167 families had a total of 329 family members with 334 malignancies (including 167 NLPHL patients and 5 members with 2 malignancies each). Of these 167 patients, 77 (46.1%) had no FM while 90 (53.9%) patients had a positive FM; 162 family members with 167 malignancies. Among these 167 families, 31 families (18.6%) had members with FHM +/- solid cancers. These 31 families had 35 family members (25 males:10 females) with 16 lymphomas: diffuse large B cell lymphoma [2], follicular center cell lymphoma [3], chronic lymphocytic leukemia/small lymphocytic lymphoma [3], non-Hodgkin lymphoma [2], classical HL [2], and NLPHL [4]. Total of 8 leukemia: acute lymphoblastic leukemia [4], acute myeloid leukemia [3], and leukemia - no subtyping [5]. These 35 FHM members are 1st [6], 2nd (16), and 3rd [7] degree relatives of 31 NLPHL patients. There are 4 families with NLPHL in family members; all these 8 NLPHL patients are male and are alive. The median total number of 1st + 2nd +3rd degree members are 81. The decrease in the age of diagnosis from 1st generation to the 2nd generation (anticipation) was noted in 13/17 patients; 2nd generation median age at diagnosis was 29.7 years vs 1st generation age 53 years (developed malignancy 23.3 years earlier).

CONCLUSION

FHM is frequent in NLPHL. This study provided us many important insights for planning future studies in terms of interviewing technique, time, and resource allocation and genetic testing.

Hodgkin lymphoma

Hodgkin lymphoma (HL) is a B cell lymphoma characterized by few malignant cells and numerous immune effector cells in the tumour microenvironment. The incidence of HL is highest in adolescents and young adults, although HL can affect elderly individuals. Diagnosis is based on histological and immunohistochemical analyses of tissue from a lymph node biopsy; the tissue morphology and antigen expression profile enable classification into one of the four types of classic HL (nodular sclerosis, mixed cellularity, lymphocyte-depleted or lymphocyte-rich HL), which account for the majority of cases, or nodular lymphocyte-predominant HL. Although uncommon, HL remains a crucial test case for progress in cancer treatment. HL was among the first systemic neoplasms shown to be curable with radiation therapy and multiagent chemotherapy. The goal of multimodality therapy is to minimize lifelong residual treatment-associated toxicity while maintaining high levels of effectiveness. Recurrent or refractory disease can be effectively treated or cured with high-dose chemotherapy followed by autologous haematopoietic stem cell transplantation, and prospective trials have demonstrated the potency of immunotherapeutic approaches with antibody-drug conjugates and immune checkpoint inhibitors. This Primer explores the wealth of information that has been assembled to understand HL; these updated observations verify that HL investigation and treatment remain at the leading edge of oncological research.

Epidemiology of classic and nodular lymphocyte predominant hodgkin lymphoma in Finland in 1996-2015

Background: The aim was to describe the incidence and mortality of Hodgkin lymphoma (HL) in Finland in 1996-2015 including classic Hodgkin lymphoma (cHL) subtypes and nodular lymphocyte predominant Hodgkin lymphoma (NLPHL).Material and Methods: This study included 2851 HL cases registered in the population-based Finnish Cancer Registry between 1996 and 2015. All not otherwise specified (NOS) morphology codes were manually checked and re-coded into cHL subtypes or NLPHL according to the International Classification of Diseases for Oncology 2011, if possible. Thereafter, we analyzed the incidence and mortality of HL by age, gender and time trends and by subtypes.Results: According to our registry-based study, the incidence of HL was increasing with a 5-year rate of change of 0.3% (95% confidence interval 0.2-0.5), and the mortality was decreasing with -2.8% (95%CI -3.8 to -1.8) correspondingly. The incidence of nodular sclerosis (NS) was 1.57/100 000 person years (n = 1529) and the incidence and mortality remained constant over 1996-2015. The incidence of mixed cellularity (MC) was 0.32/100 000 (n = 453) and it was decreasing with -2.2% (95%CI -3.7 to -0.5), yet the mortality was increasing with 2.7% (95%CI 1.9-3.6). The incidence of NLPHL was 0.29/100 000 accounting for 13% of all HL diagnoses (n = 374), and the incidence and mortality remained constant over the study period. The incidence of lymphocyte-rich (LR) subtype was 0.20/100 000 (n = 252) and remained constant while the mortality decreased. There were only 30 cases of lymphocyte depletion (LD) HL. In this study, 36% of all HL patients were over 50 years old.Conclusion: The incidence of HL is slightly increasing and the mortality is decreasing in Finland. NLPHL represents 13% of all HL cases in Finland. Over one third of HL patients are over 50-year-old.

Identification of Familial Hodgkin Lymphoma Predisposing Genes Using Whole Genome Sequencing

Hodgkin lymphoma (HL) is a lymphoproliferative malignancy of B-cell origin that accounts for 10% of all lymphomas. Despite evidence suggesting strong familial clustering of HL, there is no clear understanding of the contribution of genes predisposing to HL. In this study, whole genome sequencing (WGS) was performed on 7 affected and 9 unaffected family members from three HL-prone families and variants were prioritized using our Familial Cancer Variant Prioritization Pipeline (FCVPPv2). WGS identified a total of 98,564, 170,550, and 113,654 variants which were reduced by pedigree-based filtering to 18,158, 465, and 26,465 in families I, II, and III, respectively. In addition to variants affecting amino acid sequences, variants in promoters, enhancers, transcription factors binding sites, and microRNA seed sequences were identified from upstream, downstream, 5′ and 3′ untranslated regions. A panel of 565 cancer predisposing and other cancer-related genes and of 2,383 potential candidate HL genes were also screened in these families to aid further prioritization. Pathway analysis of segregating genes with Combined Annotation Dependent Depletion Tool (CADD) scores >20 was performed using Ingenuity Pathway Analysis software which implicated several candidate genes in pathways involved in B-cell activation and proliferation and in the network of “Cancer, Hematological disease and Immunological Disease.” We used the FCVPPv2 for further in silico analyses and prioritized 45 coding and 79 non-coding variants from the three families. Further literature-based analysis allowed us to constrict this list to one rare germline variant each in families I and II and two in family III. Functional studies were conducted on the candidate from family I in a previous study, resulting in the identification and functional validation of a novel heterozygous missense variant in the tumor suppressor gene DICER1 as potential HL predisposition factor. We aim to identify the individual genes responsible for predisposition in the remaining two families and will functionally validate these in further studies.

Analysis of 153 115 patients with hematological malignancies refines the spectrum of familial risk

Estimating familial cancer risks is clinically important in being able to discriminate between individuals in the population at differing risk for malignancy. To gain insight into the familial risk for the different hematological malignancies and their possible inter-relationship, we analyzed data on more than 16 million individuals from the Swedish Family-Cancer Database. After identifying 153 115 patients diagnosed with a primary hematological malignancy, we quantified familial relative risks (FRRs) by calculating standardized incident ratios (SIRs) in 391 131 of their first-degree relatives. The majority of hematological malignancies showed increased FRRs for the same tumor type, with the highest FRRs being observed for mixed cellularity Hodgkin lymphoma (SIR, 16.7), lymphoplasmacytic lymphoma (SIR, 15.8), and mantle cell lymphoma (SIR, 13.3). There was evidence for pleiotropic relationships; notably, chronic lymphocytic leukemia was associated with an elevated familial risk for other B-cell tumors and myeloproliferative neoplasms. Collectively, these data provide evidence for shared etiological factors for many hematological malignancies and provide information for identifying individuals at increased risk, as well as informing future gene discovery initiatives.

Genome-wide association study implicates immune dysfunction in the development of Hodgkin lymphoma

To further our understanding of inherited susceptibility to Hodgkin lymphoma (HL), we performed a meta-analysis of 7 genome-wide association studies totaling 5325 HL cases and 22 423 control patients. We identify 5 new HL risk loci at 6p21.31 (rs649775; P = 2.11 × 10-10), 6q23.3 (rs1002658; P = 2.97 × 10-8), 11q23.1 (rs7111520; P = 1.44 × 10-11), 16p11.2 (rs6565176; P = 4.00 × 10-8), and 20q13.12 (rs2425752; P = 2.01 × 10-8). Integration of gene expression, histone modification, and in situ promoter capture Hi-C data at the 5 new and 13 known risk loci implicates dysfunction of the germinal center reaction, disrupted T-cell differentiation and function, and constitutive NF-κB activation as mechanisms of predisposition. These data provide further insights into the genetic susceptibility and biology of HL.

Combined linkage and association analysis of classical Hodgkin lymphoma

The heritability of classical Hodgkin lymphoma (cHL) has yet to be fully deciphered. We report a family with five members diagnosed with nodular sclerosis cHL. Genetic analysis of the family provided evidence of linkage at chromosomes 2q35-37, 3p14-22 and 21q22, with logarithm of odds score >2. We excluded the possibility of common genetic variation influencing cHL risk at regions of linkage, by analysing GWAS data from 2,201 cHL cases and 12,460 controls. Whole exome sequencing of affected family members identified the shared missense mutations p.(Arg76Gln) in FAM107A and p.(Thr220Ala) in SLC26A6 at 3p21 as being predicted to impact on protein function. FAM107A expression was shown to be low or absent in lymphoblastoid cell lines and SLC26A6 expression lower in lymphoblastoid cell lines derived from p.(Thr220Ala) mutation carriers. Expression of FAM107A and SLC26A6 was low or absent in Hodgkin Reed-Sternberg (HRS) cell lines and in HRS cells in Hodgkin lymphoma tissue. No sequence variants were detected in KLHDC8B, a gene previously suggested as a cause of familial cHL linked to 3p21. Our findings provide evidence for candidate gene susceptibility to familial cHL.

The surprising implications of familial association in disease risk

BACKGROUND

A wide range of diseases show some degree of clustering in families; family history is therefore an important aspect for clinicians when making risk predictions. Familial aggregation is often quantified in terms of a familial relative risk (FRR), and although at first glance this measure may seem simple and intuitive as an average risk prediction, its implications are not straightforward.

METHODS

We use two statistical models for the distribution of disease risk in a population: a dichotomous risk model that gives an intuitive understanding of the implication of a given FRR, and a continuous risk model that facilitates a more detailed computation of the inequalities in disease risk. Published estimates of FRRs are used to produce Lorenz curves and Gini indices that quantifies the inequalities in risk for a range of diseases.

RESULTS

We demonstrate that even a moderate familial association in disease risk implies a very large difference in risk between individuals in the population. We give examples of diseases for which this is likely to be true, and we further demonstrate the relationship between the point estimates of FRRs and the distribution of risk in the population.

CONCLUSIONS

The variation in risk for several severe diseases may be larger than the variation in income in many countries. The implications of familial risk estimates should be recognized by epidemiologists and clinicians.

Genome-wide association study of classical Hodgkin lymphoma identifies key regulators of disease susceptibility

Several susceptibility loci for classical Hodgkin lymphoma have been reported. However, much of the heritable risk is unknown. Here, we perform a meta-analysis of two existing genome-wide association studies, a new genome-wide association study, and replication totalling 5,314 cases and 16,749 controls. We identify risk loci for all classical Hodgkin lymphoma at 6q22.33 (rs9482849, P = 1.52 × 10-8) and for nodular sclerosis Hodgkin lymphoma at 3q28 (rs4459895, P = 9.43 × 10-17), 6q23.3 (rs6928977, P = 4.62 × 10-11), 10p14 (rs3781093, P = 9.49 × 10-13), 13q34 (rs112998813, P = 4.58 × 10-8) and 16p13.13 (rs34972832, P = 2.12 × 10-8). Additionally, independent loci within the HLA region are observed for nodular sclerosis Hodgkin lymphoma (rs9269081, HLA-DPB1*03:01, Val86 in HLA-DRB1) and mixed cellularity Hodgkin lymphoma (rs1633096, rs13196329, Val86 in HLA-DRB1). The new and established risk loci localise to areas of active chromatin and show an over-representation of transcription factor binding for determinants of B-cell development and immune response.

Nonrandom occurrence of lymphoid cancer types in 140 families

We studied 140 families with two or more lymphoid cancers, including non-Hodgkin lymphoma (NHL), Hodgkin lymphoma (HL), chronic lymphocytic leukemia (CLL), and multiple myeloma (MM), for deviation from the population age of onset and lymphoid cancer co-occurrence patterns. Median familial NHL, HL, CLL and MM ages of onset are substantially earlier than comparable population data. NHL, HL and CLL (but not MM) also show earlier age of onset in later generations, known as anticipation. The co-occurrence of lymphoid cancers is significantly different from that expected based on population frequencies (p < .0001), and the pattern differs more in families with more affected members (p < .0001), suggesting specific lymphoid cancer combinations have a shared genetic basis. These families provide evidence for inherited factors that increase the risk of multiple lymphoid cancers. This study was approved by the BC Cancer Agency - University of British Columbia Clinical Research Ethics Board.

Pediatric Hodgkin lymphoma: biomarkers, drugs, and clinical trials for translational science and medicine

Hodgkin lymphoma (HL) is a lymphoid malignancy that is typically derived from germinal-center B cells. EBV infection, mutations in NF-κB pathway genes, and genetic susceptibility are known risk factors for developing HL. CD30 and NF-κB have been identified as potential biomarkers in pediatric HL patients, and these molecules may represent therapeutic targets. Although current risk adapted and response based treatment approaches yield overall survival rates of >95%, treatment of relapse or refractory patients remains challenging. Targeted HL therapy with the antibody-drug conjugate Brentuximab vedotin (Bv) has proven to be superior to conventional salvage chemotherapy and clinical trials are being conducted to incorporate Bv into frontline therapy that substitutes Bv for alkylating agents to minimize secondary malignancies. The appearance of secondary malignancies has been a concern in pediatric HL, as these patients are at highest risk among all childhood cancer survivors. The risk of developing secondary leukemia following childhood HL treatment is 10.4 to 174.8 times greater than the risk in the general pediatric population and the prognosis is significantly poorer than the other hematological malignancies with a mortality rate of nearly 100%. Therefore, identifying clinically valuable biomarkers is of utmost importance to stratify and select patients who may or may not need intensive regimens to maintain optimal balance between maximal survival rates and averting late effects. Here we discuss epidemiology, risk factors, staging, molecular and genetic prognostic biomarkers, treatment for low and high-risk patients, and the late occurrence of secondary malignancies in pediatric HL.