The familial risk of Hodgkin's lymphoma ranks among the highest in the Swedish Family-Cancer Database

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.

The Mutation of CD27 Deficiency Presented With Familial Hodgkin Lymphoma and a Review of the Literature

This study aimed to report 4 siblings with CD27 deficiency presented with Hodgkin lymphoma. The father of the family, his 2 wives, and 17 children born from these wives were included into the study. CD27 mutation of all the family members with, and without Hodgkin lymphoma were studied. The variants detected by the exome sequencing analysis were verified by Sanger sequencing and analyzed using SeqScape Software 3. It was determined that both the father of the family and his 2 wives carried the same variant heterozygously. Of the children born to the first mother, 2 children were normal, 3 were heterozygous and 5 were homozygous. Four of these 5 homozygous children were diagnosed with Hodgkin lymphoma. Of the children born to the second mother, 1 child was normal, 3 children were heterozygous and 2 children were homozygous, and none of them had developed a malignant event. We also showed that CD27 deficiency may enhance Treg differentiation. According to our information, this study augmented the relationship of Hodgkin lymphoma and CD27 deficiency. The detection of homozygous CD27 variant in all siblings who developed lymphoma strengthened the place of this mutation in the etiology of Hodgkin lymphoma. In contrast, the presence of homozygous siblings with no malignant event suggested the possible contributions of environmental factors on the etiology.

Genetic predisposition to lymphomas: Overview of rare syndromes and inherited familial variants

Approximately 10 % of malignancies occur in carriers of germline mutations predisposing to cancer. A high risk of developing lymphomas has been noted in many primary immunodeficiencies, including DNA repair disorders. Moreover, implementation of next-generation sequencing has recently enabled to uncover rare genetic variants predisposing patients to lymphoid neoplasms. Some patients harboring inherited predisposition to lymphomas require dedicated clinical management, which will contribute to effective cancer treatment and to the prevention of potential severe toxicities and secondary malignancies. In line with that, our review summarizes the natural history of lymphoid tumors developing on different germline genetic backgrounds and discusses the progress that has been made toward successfully treating these 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.

Sex chromosome loss and the pseudoautosomal region genes in hematological malignancies

Cytogenetic aberrations, such as chromosomal translocations, aneuploidy, and amplifications, are frequently detected in hematological malignancies. For many of the common autosomal aberrations, the mechanisms underlying their roles in cancer development have been well-characterized. On the contrary, although loss of a sex chromosome is observed in a broad range of hematological malignancies, how it cooperates in disease development is less understood. Nevertheless, it has been postulated that tumor suppressor genes reside on the sex chromosomes. Although the X and Y sex chromosomes are highly divergent, the pseudoautosomal regions are homologous between both chromosomes. Here, we review what is currently known about the pseudoautosomal region genes in the hematological system. Additionally, we discuss implications for haploinsufficiency of critical pseudoautosomal region sex chromosome genes, driven by sex chromosome loss, in promoting hematological malignancies. Because mechanistic studies on disease development rely heavily on murine models, we also discuss the challenges and caveats of existing models, and propose alternatives for examining the involvement of pseudoautosomal region genes and loss of a sex chromosome in vivo. With the widespread detection of loss of a sex chromosome in different hematological malignances, the elucidation of the role of pseudoautosomal region genes in the development and progression of these diseases would be invaluable to the field.

Whole exome sequencing in families at high risk for Hodgkin lymphoma: identification of a predisposing mutation in the KDR gene

Hodgkin lymphoma shows strong familial aggregation but no major susceptibility genes have been identified to date. The goal of this study was to identify high-penetrance variants using whole exome sequencing in 17 Hodgkin lymphoma prone families with three or more affected cases or obligate carriers (69 individuals), followed by targeted sequencing in an additional 48 smaller HL families (80 individuals). Alignment and variant calling were performed using standard methods. Dominantly segregating, rare, coding or potentially functional variants were further prioritized based on predicted deleteriousness, conservation, and potential importance in lymphoid malignancy pathways. We selected 23 genes for targeted sequencing. Only the p.A1065T variant in KDR (kinase insert domain receptor) also known as VEGFR2 (vascular endothelial growth factor receptor 2) was replicated in two independent Hodgkin lymphoma families. KDR is a type III receptor tyrosine kinase, the main mediator of vascular endothelial growth factor induced proliferation, survival, and migration. Its activity is associated with several diseases including lymphoma. Functional experiments have shown that p.A1065T, located in the activation loop, can promote constitutive autophosphorylation on tyrosine in the absence of vascular endothelial growth factor and that the kinase activity was abrogated after exposure to kinase inhibitors. A few other promising mutations were identified but appear to be "private". In conclusion, in the largest sequenced cohort of Hodgkin lymphoma families to date, we identified a causal mutation in the KDR gene. While independent validation is needed, this mutation may increase downstream tumor cell proliferation activity and might be a candidate for targeted therapy.

Familial predisposition and genetic risk factors for lymphoma

Our understanding of familial predisposition to lymphoma (collectively defined as non-Hodgkin lymphoma [NHL], Hodgkin lymphoma [HL], and chronic lymphocytic leukemia [CLL]) outside of rare hereditary syndromes has progressed rapidly during the last decade. First-degree relatives of NHL, HL, and CLL patients have an ∼1.7-fold, 3.1-fold, and 8.5-fold elevated risk of developing NHL, HL, and CLL, respectively. These familial risks are elevated for multiple lymphoma subtypes and do not appear to be confounded by nongenetic risk factors, suggesting at least some shared genetic etiology across the lymphoma subtypes. However, a family history of a specific subtype is most strongly associated with risk for that subtype, supporting subtype-specific genetic factors. Although candidate gene studies have had limited success in identifying susceptibility loci, genome-wide association studies (GWAS) have successfully identified 67 single nucleotide polymorphisms from 41 loci, predominately associated with specific subtypes. In general, these GWAS-discovered loci are common (minor allele frequency >5%), have small effect sizes (odds ratios, 0.60-2.0), and are of largely unknown function. The relatively low incidence of lymphoma, modest familial risk, and the lack of a screening test and associated intervention, all argue against active clinical surveillance for lymphoma in affected families at this time.

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

We aimed to provide the familial risk of classical Hodgkin lymphoma (HL) by relationship, histology, age at diagnosis, and sex. A cohort of 57,475 first-degree relatives of 13,922 HL patients diagnosed between 1955 and 2009 in 5 European countries was observed for HL incidence. The overall lifetime cumulative risk (CR) of HL in first-degree relatives of a patient with HL was 0.6%, which represents a threefold (standardized incidence ratio [SIR], 3.3; 95% confidence interval [CI], 2.8-3.9) increased risk over the general population risk. The risk in siblings (6.0-fold; 95% CI, 4.8- to 7.4-fold) was significantly higher than in parents and/or children (2.1-fold; 95% CI, 1.6- to 2.6-fold). Very high lifetime risk of HL was found for those with multiple affected first-degree relatives (13-fold; 95% CI, 2.8- to 39-fold) and for same-sex twins (57-fold; 95% CI, 21- to 125-fold). We found high familial risks between some concordant histologic subtypes of HL such as lymphocyte-rich (81-fold; 95% CI, 30- to 177-fold) and nodular sclerosis (4.6-fold; 95% CI, 2.9- to 7.0-fold) and also between some discordant subtypes. The familial risk in sisters (9.4-fold; 95% CI, 5.9- to 14-fold) was higher than in brothers (4.5-fold; 95% CI, 2.9- to 6.7-fold) or unlike-sex siblings (5.9-fold; 95% CI, 4.3- to 8.1-fold). The lifetime risk of HL was higher when first-degree relatives were diagnosed at early ages (before age 30 years). This study provides tangible absolute risk estimates for relatives of HL patients, which can be used as a sex-, age-, and family history-based risk calculator for classical HL by oncologists and genetic counselors.

Family history of cancer and risk of pediatric and adolescent Hodgkin lymphoma: A Children's Oncology Group study

Family history of lymphoid neoplasm (LN) is a strong and consistently observed Hodgkin lymphoma (HL) risk factor, although it has been only marginally examined in pediatric/adolescent patients. Here, healthy control children identified by random digit dialing were matched on sex, race/ethnicity and age to HL cases diagnosed at 0-14 years at Children's Oncology Group institutions in 1989-2003. Detailed histories were captured by structured telephone interviews with parents of 517 cases and 783 controls. Epstein-Barr virus (EBV) RNA detection was performed for 355 available case tumors. Two analytic strategies were applied to estimate associations between family cancer history and pediatric/adolescent HL. In a standard case-control approach, multivariate conditional logistic regression was used to calculate odds ratios and 95% confidence intervals (CIs). In a reconstructed cohort approach, each relative was included as a separate observation, and multivariate proportional hazards regression was used to produce hazard ratios (HRs) and 95% CIs. Using the latter, pediatric/adolescent HL was associated with a positive family history (HR = 1.20, 95% CI: 1.06-1.36), particularly early-onset cancers (HR = 1.30, 95% CI: 1.06-1.59) and those in the paternal lineage (HR = 1.38, 95% CI: 1.16-1.65), with a suggested association for LN in first-degree relatives (HR = 3.61, 95% CI: 0.87-15.01). There were no discernable patterns for EBV+ versus EBV- HL. The clustering of LN within pedigrees may signal shared genetic susceptibility or common environmental exposures. Heritable genetic risk variants have only recently begun to be discovered, however. These results are consistent with other studies and provide a compelling rationale for family-based studies to garner information about genetic susceptibility to HL.

Epidemiological Overview of Hodgkin Lymphoma across the Mediterranean Basin

The epidemiology of Hodgkin lymphoma (HL) has always been a source of fascination to researchers due to its heterogeneous characteristics of presentation. HL is an uncommon neoplasm of B-cell origin with an incidence that varies significantly by age, sex, ethnicity, geographic location and socioeconomic status. This complex pattern was also found to be replicated among Mediterranean basin populations. HL incidence rates progressively decreased from industrialized European countries such as France (ASR=2.61) and Italy (ASR=2.39) to less developed nations such as Albania (ASR=1.34) and Bosnia Herzegovina (ASR=1.1). Regarding HL mortality we have found that countries with the lowest incidence rates show the highest number of deaths from this cancer and viceversa. Finally, a wide gap in terms of survival was showed across the Mediterranean basin with survival rates ranged from 82.3% and 85.1% among Italian men and women, to 53.3 % and 59.3% among Libyan men and women, respectively. Factors such as the degree of socio-economic development, the exposure to risk factors westernization-related, the availability of diagnostic practices along with different genetic susceptibilities to HL may explain its variation across Mediterranean countries. Furthermore, the lack of health resources decisively contribute to the poor prognosis recorded in less developed region. In the future, the introduction of appropriate and accessible treatment facilities along with an adequate number of clinical specialists in the treatment of HL and other cancers are warranted in order to improve the outcomes of affected patients and treat a largely curable type of cancer in disadvantaged regions.

Interleukin-10 gene polymorphisms are associated with freedom from treatment failure for patients with Hodgkin lymphoma

BACKGROUND

Hodgkin lymphoma (HL) is a lymphoid malignancy characterized by the production of various cytokines possibly involved in immune deregulation. Interleukin-10 (IL-10) serum levels have been associated with clinical outcome in patients with HL. Because host genetic variations are known to alter the expression and function of cytokines and their receptors, we investigated whether genetic variations influence clinical outcome of patients with HL.

METHODS

A total of 301 patients with HL who were treated within randomized trials by the German Hodgkin Study Group were included in this exploratory retrospective study. Gene variations of IL-10 (IL-10(-597AC), rs1800872; IL-10(-824CT), rs1800871; IL-10(-1087AG), rs1800896; IL-10(-3538AT), rs1800890; IL-10(-6208CG), rs10494879; IL-10(-6752AT), rs6676671; IL-10(-7400InDel)), IL-13 (IL-13(-1069CT), rs1800925; IL-13(Q144R), rs20541), and IL-4R (IL-4R(I75V), rs1805010; IL-4R(Q576R), rs1801275) were genotyped.

RESULTS

Inferior freedom from treatment failure (FFTF) was found in patients harboring the IL-10(-597AA), IL-10(-824TT), or the IL-10(-1087AA) genotype. In contrast, the IL-10(-1087G-824C-597C) haplotype present in about 48% of analyzed HL patients is nominally significant for a better FFTF in a Cox-Regression model accounting for stage and treatment. No associations were observed between the other IL-10 gene variations, IL-13(-1069CT), IL-13(Q144R), IL-4R(I75V), IL-4R(Q576R) and the clinical outcome of patients with HL.

CONCLUSIONS

Our study provides further evidence that proximal IL-10 promoter gene variations are associated with clinical course of patients with HL. However, treatment success and survival rates are already at a very high rate, supporting the need to design studies focusing on identification of predictors to reduce the side effects of therapy.

KLHDC8B in Hodgkin lymphoma and possibly twinning

A key feature of Hodgkin lymphoma is that the malignant cells are binucleated, as a consequence of failed cytokinesis. We recently ascertained a family in which multiple cases of Hodgkin lymphoma had occurred among individuals who inherited a balanced chromosomal translocation. We cloned the translocation breakpoints and found that it disrupted a previously uncharacterized gene, KLHDC8B, encoding a Kelch family protein whose deficiency impairs cytokinesis and leads to binucleated cells. In other families we found a rare single nucleotide polymorphism affecting mitotic translation of KLHDC8B that was associated with and linked to Hodgkin lymphoma. Interestingly, the index family demonstrated an unusual frequency of twins, and there is a previously reported association between Hodgkin lymphoma and twins. Here we review the unusual genetic features of Hodgkin lymphoma, including gender concordance among siblings, and genetically test the hypothesis that KLHDC8B may participate in twinning by disrupting cytokinesis through impediment of polar body separation from oocytes.

Heritability of hematologic malignancies: from pedigrees to genomics

Many hematologic malignancies have an underlying heritable component. Although not as well characterized as the acquired genetic abnormalities that define important prognostic and therapeutic subgroups of myeloid and lymphoid neoplasms, investigations are beginning to unravel the role of germline genetic variation in the predisposition to hematologic malignancies. Information gained from the study of striking family pedigrees, epidemiologic data, and candidate genes are now being combined with unbiased genome-wide investigations to outline the network of genetic abnormalities that contribute to hematologic malignancy risk. This article reviews the current understanding of the heritability of hematologic malignancies in the genomics era.

Mutations in a gene encoding a midbody protein in binucleated Reed-Sternberg cells of Hodgkin lymphoma

Classical Hodgkin lymphoma (cHL) is a cancer in which malignant "Reed-Sternberg" cells comprise just a fraction of the bulk of the tumor and are characteristically binucleated. We recently identified a novel gene, KLHDC8B, which appears responsible for some familial cases of cHL. KLHDC8B encodes a midbody kelch protein expressed during cytokinesis. Deficiency of KLHDC8B leads to binucleated cells, implicating its involvement in Reed-Sternberg cell formation. Interestingly, other cancer genes, such as BRCA1 and BRCA2, also encode proteins locating to the midbody during cytokinesis, even though their participation in other pathways has received greater attention. Midbody components may be an overlooked source of tumor suppressor genes.

Familial Hodgkin's lymphoma from the perspective of HLA

Although the incidence of Hodgkin lymphoma (HL)--a lymphoid tissue malignity--increases in the presence of several viruses, particularly EBV, as well as with autoimmune diseases and following transplantation, although to date, the exact etiopathogenesis is not known. The higher frequency of HL among family members suggests involvement of genetic factors in its etiology. Studies aiming to elucidate the etiopathogenesis of patients with familial HL (FHL) have reported that human leukocyte antigen (HLA) haplotypes might be involved. In this case presentation, the associations between HLs diagnosed in a father of consanguineous marriage and his two children and HLAs in other family members were investigated and the findings are discussed in view of the published literature; no direct association was found between HLA alleles and the development of the disease in the present case with familial HL.

IRF4 polymorphism rs872071 and risk of Hodgkin lymphoma

The reciprocal familial risk between chronic lymphocytic leukaemia (CLL) and Hodgkin lymphoma (HL) suggests genetic variants with pleiotropic effects may influence the risk of both CLL and HL. We have recently shown that the IRF4 variant rs872071 influences CLL risk. To examine if rs872071 genotype is associated with HL risk we genotyped two case-control series (totalling, 529 and 2192, respectively). This analysis provides evidence that IRF4 rs872071 influences HL risk; Odds Ratio = 1.21 (95% confidence interval: 1.05-1.39, P = 0.009) and highlights the importance of inherited variation in B-cell developmental genes in the development of HL.

Clinical significance of interleukin-10 gene polymorphisms and plasma levels in Hodgkin lymphoma

We studied plasma levels of IL-10 and five single nucleotide polymorphisms in the interleukin-10 (IL-10) gene promoter in patients with Hodgkin lymphoma (HL) to address potential genotype-phenotype correlations. Patients with elevated IL-10 levels were more likely to have advanced stage disease and inferior event-free survival. Homozygous carriers of the variant alleles at position -592 (AA) and -1082 (GG) of the IL-10 promoter had higher IL-10 plasma levels, independent of male gender and advanced stage of disease which also determined increased IL-10 production. This analysis indicates that the genetic background can modulate plasma levels of IL-10, and ultimately prognosis in HL.

Interleukin-2, interleukin-12, and interferon-gamma levels and risk of young adult Hodgkin lymphoma

Young adult Hodgkin lymphoma (YAHL) is associated clinically with altered immunity, including a systemic defect in cell-mediated responses. There is strong evidence of a genetic contribution to risk, so we hypothesized that heritable alterations in cytokine production associated with Th1 function may contribute to susceptibility. We identified twin pairs in whom at least one member had YAHL and measured interleukin-2 (IL-2), interleukin-12 (IL-12), and interferon-gamma (IFN-gamma) levels in PHA-stimulated peripheral blood mononuclear cell supernatant in 90 case-twins, 84 of their disease-free twins (unaffected cotwins), and 90 matched controls. Mean difference and mean percentage difference in cytokine levels between case-twins and controls, and unaffected cotwins and controls were determined using analysis of covariance. YAHL case-twins and their unaffected cotwins had IL-12 levels that were 60.6% (P=.002) and 49% (P=.04) lower than those of their matched controls, respectively. IL-2 levels were significantly higher in case-twins (P=.049), but not unaffected cotwins (P=.57), compared with controls. Differences in IFN-gamma levels were not statistically significant in either comparison. An IL-12 polymorphism known to regulate expression was associated with a 2.8-fold (P=.03) increase in YAHL risk. Thus, both case-twins and their unaffected cotwins had a decreased ability to produce IL-12, which may contribute to YAHL susceptibility.

Family history of cancer in children with acute leukemia, Hodgkin's lymphoma or non-Hodgkin's lymphoma: the ESCALE study (SFCE)

The role of a family history of cancer in the etiology of childhood hematopoietic malignancies was investigated using the data from the ESCALE study. ESCALE, a population-based case-control study, was carried out in France over the period, 2003-2004. A total of 773 cases of acute leukemia (AL), 130 of Hodgkin's lymphoma (HL), 163 of non-Hodgkin's lymphoma (NHL) and 1,681 population-based controls were included. The controls were randomly selected from the French population and were frequency matched with the cases on age and gender. Cancer history in first- and second-degree relatives was reported by the mothers in a structured telephone questionnaire that was the same for the cases and controls. Odds ratios (ORs) were estimated using an unconditional regression model taking into account the stratification variables and potential confounders. A family history of cancer was associated with an increased risk of HL (OR = 1.5 [1.0-2.2]) and NHL (OR = 1.8 [1.3-2.5]), but not AL (OR = 1.0 [0.9-1.2]). The ORs were higher when at least 2 relatives had a history of cancer or when 1 case occurred before age 46 years. Only HL was significantly associated with a family history of hematopoietic malignancies (OR = 2.0 [1.0-3.8]), mainly because of a significant association with a history of HL (OR = 5.4 [1.3-22]). In conclusion, the study findings support the hypothesis of familial susceptibility to childhood lymphoma, but do not suggest familial susceptibility to childhood AL.