Current insight on trends, causes, and mechanisms of Hodgkin's lymphoma

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.

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.

Germline mutations in Protection of Telomeres 1 in two families with Hodgkin lymphoma

In a previous whole exome sequencing of patients from 41 families with Hodgkin lymphoma, we identified two families with distinct heterozygous rare coding variants in POT1 (D224N and Y36H), both in a highly conserved region of the gene. POT1 D224N mutant did not bind to a single-stranded telomere oligonucleotide in vitro suggesting the mutation perturbs POT1's ability to bind to the telomeric G-rich overhang. Human HT1080 cells expressing POT1 D224N and lymphoblastoid cells carrying Y36H both showed increased telomere length and fragility in comparison to wild type cells. This strongly suggests that mutant POT1 causes chromosome instability and may play a role in lymphomagenesis in these families.

Incidence and survival of Hodgkin lymphoma patients in Girona (Spain) over three decades: a population-based study

Hodgkin lymphoma (HL) is characterized by heterogeneous histologic findings, clinical presentation and outcomes. Using the Girona population-based cancer registry data we sought to explore the incidence of HL over three decades in Girona Province (Spain) and examine the relationship between clinical features at diagnosis and survival. From 1985 to 2013, 459 cases were recorded. Patients were stratified by sex, age group, stage at diagnosis, histological subtypes and the presence of B-symptoms. The crude incidence rate (CR) was 2.7 and the corresponding European age-adjusted rate was 2.6, being higher in men than in women (sex ratio=1.6). Incidence remained constant throughout the period of study. Nodular sclerosis was the most frequent histology and showed an increasing incidence over time [estimated annual percentage change=+2.4, 95% confidence interval (CI): 0.8-4.0]. The 5-year observed survival and relative survival of patients diagnosed with HL were 73.1% (95% CI: 69.0-77.5) and 74.6% (95% CI: 70.0-79.4), respectively. No statistical differences in observed survival were observed across the three decades of study (P=0.455). Clinical parameters negatively influencing 5-year relative survival in the multivariate analysis were as follows: age at diagnosis at least 65 years; clinical stage IV; and presence of B-symptoms. These current patterns of presentation and outcomes of HL help delineate key populations in order to explore risk factors for HL and strategies to improve treatment outcomes.

Hodgkin lymphoma burden in Central and South America

RATIONALE AND OBJECTIVE

Hodgkin lymphoma (HL) is largely curable owing to improvements in treatment since the 1960s; nevertheless, high mortality rates have been reported in Central and South America. We describe the current burden of HL in the Central and South American region.

METHODS

We obtained regional- and national-level incidence data from 48 population-based cancer registries in 13 countries, and national-level mortality data from the WHO mortality database for 18 countries. We estimated world population age-standardized incidence rates (ASRs) and age-standardized mortality rates (ASMRs) per 100,000 person-years for 2003-2007 and present distributions by histological subtype.

RESULTS

HL incidence rates varied 7-fold in males and 11-fold in females (male-to-female ratio 1:1-2.5:1). The highest ASRs were seen Argentina, Brazil, Costa Rica (males), Cuba (males) and Uruguay (females), whereas the lowest were in Bolivia and El Salvador. ASMRs varied by 4-fold in males and 6-fold in females (male-to-female ratio 1:1-4.3:1), with ASMRs <0.7 for most countries, except Cuba (≥1.0). In most countries, age-specific incidence rates of HL showed a bimodal pattern. Trends in HL in Argentina, Brazil, Chile, and Costa Rica remained stable in 1997-2008. Of all HL cases, 48% were unspecified as to histological subtype. Nodular sclerosis and mixed cellularity were the most frequent histologies.

CONCLUSION

The geographic variation in HL across the region may in part reflect differences in data quality and coverage, and differences in the adoption of modern therapies and healthcare access. Our results highlight the need for high-quality data and increased coverage in order to provide vital guidance for future cancer control activities.

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.

Predispositions to Lymphoma: A Practical Review for Genetic Counselors

This review provides a synopsis for genetic counselors of the major concepts of lymphoma predisposition: genomic instability, immune deficiency, inappropriate lymphoproliferation, and chronic antigen stimulation. We discuss syndromes typifying each of these mechanisms. Importantly, our review of the genetic counseling literature reveals sparse discussion of genetically-based immune-mediated lymphoma predisposition, which we address in depth here. We aim to increase awareness among genetic counselors and colleagues in oncology about familial susceptibility and facilitate critical thinking about lymphoma risk assessment. Clinical application of this knowledge is aided by recommendations for collection of personal and family history to guide risk assessment and testing. Lastly, we include a special discussion of genetic counseling issues including perceptions of the context, nature, and magnitude of lymphoma risk, as well as coping with awareness of susceptibility to lymphoma.

Childhood exposures among mothers and Hodgkin's lymphoma in offspring

BACKGROUND

Childhood exposures in mothers, signaled by number of older and younger siblings, have lifelong consequences for aspects of immune function. We hypothesized that these may influence young adult-onset Hodgkin's lymphoma (HL) risk in offspring.

MATERIALS AND METHODS

Swedish registers identified 2028 cases of young adult onset HL (diagnosed between ages 15-39 years) up to 2012 among those born since 1958; and 18,374 matched controls. Conditional logistic regression was used to assess HL risk associated with number of older and younger siblings of mothers.

RESULTS

Having a mother with more than two older siblings is associated with lower HL risk, and the association is statistically significant for mothers with three or more siblings, compared with none. The adjusted odds ratios (and 95% confidence intervals) are 1.04 (0.93-1.16); 0.95 (0.81-1.10); and 0.81 (0.66-0.98) for one, two, and three or more older siblings, respectively. There is no association between number of mothers' younger siblings and HL risk.

CONCLUSIONS

Exposures during the childhood of mothers may influence young onset adult HL risk in offspring, perhaps through vertical transmission of infectious agents, or through other long-term influences on maternal immune function.

Time Trends in Rates of Hodgkin Lymphoma Histologic Subtypes: True Incidence Changes or Evolving Diagnostic Practice?

BACKGROUND

Histologic subtypes of classical Hodgkin lymphoma [cHL; e.g., nodular sclerosis, mixed cellularity, not otherwise specified (NOS)] are epidemiologically and prognostically distinctive. Therefore, unexplained, ongoing incidence rate declines for mixed cellularity and increases for NOS require examination.

METHODS

We analyzed detailed histology-specific Hodgkin lymphoma incidence rates in 1992 through 2011 U.S. SEER data (n = 21,372) and reviewed a regional subset of 2007 through 2011 NOS pathology reports for insight into diagnostic practices.

RESULTS

cHL rates were stable until 2007, then decreased for whites [annual percent change (APC) and 95% confidence interval (CI), -3.6% (-5.6% to -1.5%)]. Nodular sclerosis rates declined after 2007 by 5.9% annually, with variation by gender, age, and race/ethnicity. In 1992 through 2011, mixed cellularity rates declined [APC -4.0% (-4.7% to -3.3%)], whereas NOS rates rose [5.3% (4.5%-6.2%)] overall and in most patient groups. The 2007-2011 NOS age-specific rates were more similar to mixed cellularity rates for 1992-1996 than 2007-2011. Trends in combined rates were minimal, supporting increasing misclassification of mixed cellularity, lymphocyte depletion, and specific nodular sclerosis subtypes as NOS. Eighty-eight of 165 reviewed NOS pathology reports addressed classification choice. Twenty (12.1%) justified the classification, 21 (12.7%) described insufficient biopsy material, and coders missed specific subtype information for 27 (16.4%).

CONCLUSION

Recent nodular sclerosis rate declines largely represent true incidence changes. Long-term rate decreases for mixed cellularity and other less common subtypes, and increases for NOS (comprising ∼30% of cHL cases in 2011), likely reflect changes in diagnostic and/or classification practice.

IMPACT

Diminishing histologic subtyping undermines future surveillance and epidemiologic study of Hodgkin lymphoma. Guideline-based use of excisional biopsies and more coding quality control are warranted.

Hodgkin lymphoma incidence in ethnic enclaves in California

Hodgkin lymphoma (HL) incidence varies with migration and nativity, suggesting an influence of acculturation on risk. In population-based California data including 1483 Hispanic and 348 Asian/Pacific Islander (API) HL cases, we examined HL rates in residential neighborhoods classified by ethnic enclave status (measuring degree of acculturation) and socioeconomic status (SES). Rates were inversely associated with enclave intensity, although associations varied by gender and race. In females, the enclave effect was stronger in low-SES settings, but rates were higher in less-ethnic/high-SES than more-ethnic/low-SES neighborhoods--diminishing enclave intensity affected rates more than higher SES. In Hispanics, associations were modest, and only females experienced SES modification of rates; in APIs, the enclave effect was much stronger. Thus, acculturation measured by residence in ethnic enclaves affects HL rates independently of neighborhood SES but in complex patterns. Living in less-ethnic neighborhoods may increase HL rates by facilitating social isolation and other gender-specific exposures implicated in risk.

Hodgkin lymphoma risk following infectious and chronic inflammatory diseases: a large population-based case-control study from Sweden

Patients with Hodgkin lymphoma (HL) have a well-characterized immune deficiency of T cell function, originally identified by increased susceptibility to certain infections. Epidemiological evidence has long pointed to infectious etiologies in younger HL patients. With the aim of expanding our knowledge on the potential role of pre-existing immune deficiency in HL and an infectious/inflammatory etiology, we conducted a comprehensive population-based case-control study in HL patients diagnosed in Sweden in the period 1965-2004, and their matched controls. In a large population-based study including 7,414 HL patients and 29,240 matched controls, we evaluated the subsequent risk of HL in relation to a broad range of infectious and inflammatory conditions, using unconditional logistic regression. A previous history of any reported infection was associated with an 11 % increased risk of HL (P < 0.05). More specifically, we found sinusitis (odds ratio = 1.81; 95 % confidence interval = 1.06-3.07), tuberculosis (1.76; 1.01-3.07), encephalitis (7.88; 1.97-31.5), and herpes zoster (2.20; 1.11-4.35) to be associated with excess HL risk. A personal prior history of chronic inflammatory condition was not associated with an increased risk of HL (0.94; 0.71-1.14). Our results suggest that underlying immune deficiency is a primary phenomenon in HL. Alternatively, certain infectious agents may be potential HL triggers.

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.

Neutropenia and Neutropenic Complications in ABVD Chemotherapy for Hodgkin Lymphoma

A combination of Adriamycin (a.k.a. Doxorubicin), Bleomycin, Vinblastine, and Dacarbazine (ABVD) is the most commonly used chemotherapy regime for Hodgkin lymphoma. This highly effective treatment is associated with a significant risk of neutropenia. Various strategies are adopted to counter this commonly encountered problem, including dose modification, use of colony stimulating factors, and prophylactic or therapeutic use of antibiotics. Data to support these approaches is somewhat controversial, and in keeping with the paucity of definitive evidence, there is a wide disparity in the management of neutropenia in patients receiving ABVD chemotherapy. This paper summarizes the evidence for managing ABVD-related neutropenia during the treatment of Hodgkin lymphoma.

Association of JAK-STAT pathway related genes with lymphoma risk: results of a European case-control study (EpiLymph)

Previous studies have suggested an important role for the Janus kinase-signal transducer and activator of transcription (JAK-STAT) signalling pathway in tumour development. Therefore, we explored genetic variants in JAK-STAT pathway associated genes with lymphoma risk. In samples of the EpiLymph case-control study we genotyped 1536 single nucleotide polymorphisms (SNPs) using GoldenGate BeadArray™ Technology (Illumina, San Diego, CA, USA). Here, we report the associations between selected SNPs and haplotypes of the JAK-STAT pathway and risk of Hodgkin lymphoma (HL), B-cell non-Hodgkin lymphoma (B-NHL) and most frequent B-NHL subtypes. Among 210 relevant JAK-STAT pathway-related SNPs, polymorphisms in nine genes (BMF, IFNG, IL12A, SOCS1, STAT1, STAT3, STAT5A, STAT6, TP63) were significantly associated with lymphoma risk. At a study-wise significance level, we obtained a risk reduction of 28% among carriers of the heterozygous genotype of the STAT3 variant (rs1053023) for B-NHL. For six other variants within the STAT3 gene we observed an inverse association with different lymphoma subtypes. A reduced risk for HL was observed for the heterozygous genotype of the STAT6 SNP (rs324011). This is an explorative investigation to examine associations between JAK-STAT signalling related genes and lymphoma risk. The results implicate a relevant role of certain pathway-related genes in lymphomagenesis, but still need to be approved by independent studies.

[Hodgkin's Lymphoma]

With approximately 1500 cases per year in France, Hodgkin's lymphoma (HL) represents only 10 to 15 % of new cases of lymphomas, and 0.5 to 1 % of new cases of cancers. The management of this lymphoproliferative disease has undergone profound conceptual changes over time, allowing at present to obtain a cure rate of 75 to 80 % of all confused stage, and up to 90 % in case of early stage HL. If initial treatment consisted in an exclusive extensive (total or sub-total lymphoid) irradiation whatever the stage may be, the place of radiotherapy in the management of HL has evolved over time but remains today one of the cornerstones of the treatment. It becomes integrated within the framework of combined modality therapies associating chemotherapy then irradiation for the early stage HL, and stays a therapeutic alternative in all situations (in advanced stage and\or recurrent disease) which raises the issue of increasing the locoregional tumor control. Despite the undeniable contribution of radiotherapy in controlling the disease, delayed side effects of treatments are not negligible. So the long-term monitoring of treated patients is essential, mainly because of an increased risk of morbi-mortality due to cardiovascular events and/or secondary cancers. It is important to remember that even today the "Involved Field" irradiation type remains the gold standard, even if we witness at present the emergence of new types of irradiation, which aim to reduce the amount of irradiated tissues to try to limit the risks of delayed radio-induced complications. The purpose of this article is to clarify the specific aspects (epidemiological, radio-anatomical and prognostic characteristics) of HL, as well as the practical modalities of the irradiation (illustrated by a clinical case record) when an indication of radiotherapy is placed for its treatment.

Physical activity and hematologic cancer prevention

This chapter presents the epidemiologic evidence on the association between physical activity and hematologic cancers and related hypothesized biologic mechanisms. Some preliminary indications of a protective role for physical activity for non-Hodgkin's lymphoma, leukemia, multiple myeloma, and Hodgkin's lymphoma exist, but the level of epidemiologic evidence is still insufficient to make any definitive conclusions regarding the nature of these associations. Several plausible biologic mechanisms underlying the possible associations between physical activity and hematologic cancers have been proposed, including enhancement of immune function, reduction in obesity, improvement of antioxidant defense systems, impact on metabolic hormones, and anti-inflammatory effects. Future studies should improve the estimation of physical activity by using more reliable, valid, and comprehensive measurement tools, assessing all components of physical activity (type, intensity, and time period), and conducting intervention studies to evaluate the effect of physical activity on various biomarkers of cancer in order to provide further insight into plausible biologic mechanisms underlying the possible association between physical activity and hematologic cancers.