Familial aggregation and heterogeneity of non-Hodgkin lymphoma in population-based samples

Immune dysregulation as a leading principle for lymphoma development in diverse immunological backgrounds

Lymphoma is a heterogeneous group of malignancies arising from lymphocytes, which poses a significant challenge in terms of diagnosis and treatment due to its diverse subtypes and underlying mechanisms. This review aims to explore the shared and distinct features of various forms of lymphoma predisposing conditions, with a focus on genetic, immunological and molecular aspects. While diseases such as autoimmune disorders, inborn errors of immunity and iatrogenic immunodeficiencies are biologically and immunologically distinct, each of these diseases results in profound immune dysregulation and a predisposition to lymphoma development. Interestingly, the increased risk is often skewed towards a particular subtype of lymphoma. Patients with inborn errors of immunity in particular present with extreme forms of lymphoma predisposition, providing a unique opportunity to study the underlying mechanisms. External factors such as chronic infections and environmental exposures further modulate the risk of lymphoma development. Common features of conditions predisposing to lymphoma include: persistent inflammation, recurrent DNA damage or malfunctioning DNA repair, impaired tumor surveillance and viral clearance, and dysregulation of fundamental cellular processes such as activation, proliferation and apoptosis. Our growing understanding of the underlying mechanisms of lymphomagenesis provides opportunities for early detection, prevention and tailored treatment of lymphoma development.

Epidemiology and etiology of diffuse large B-cell lymphoma

As the most common non-Hodgkin lymphoma subtype, diffuse large B-cell lymphoma (DLBCL) incidence patterns generally parallel that for NHL overall. Globally, DLBCL accounts for a third of all NHLs, ranging between 20% and 50% by country. Based on United States (U.S.) cancer registry data, age-standardized incidence rate for DLBCL was 7.2 per 100,000. DLBCL incidence rises with age and is generally higher in males than females; in the U.S., incidence is highest among non-Hispanic whites (9.2/100,000). Like NHL incidence, DLBCL incidence rose in the first half of the 20th century but has largely plateaued. However, there is some evidence that incidence rates are rising in areas of historically low rates, such as Asia; there are also estimates for rising DLBCL incidence in the near future due to the changing demographics in developed countries whose aging population is growing. Established risk factors for DLBCL include those that result in severe immune deficiency such as HIV/AIDS, inherited immunodeficiency syndromes, and organ transplant recipients. Factors that lead to chronic immune dysregulations are also established risk factors, and include a number of autoimmune conditions (eg, Sjögren syndrome, systemic lupus erythematosus, rheumatoid arthritis), viral infections (eg, HIV, KSHV/HHV8, HCV, EBV), and obesity. Family history of NHL/DLBCL, personal history of cancer, and multiple genetic susceptibility loci are also well-established risk factors for DLBCL. There is strong evidence for multiple environmental exposures in DLBCL etiology, including exposure to trichloroethylene, benzene, and pesticides and herbicides, with recent associations noted with glyphosate. There is also strong evidence for associations with other viruses, such as HBV. Recent estimates suggest that obesity accounts for nearly a quarter of DLBCLs that develop, but despite recent gains in the understanding of DLBCL etiology, the majority of disease remain unexplained. An understanding of the host and environmental contributions to disease etiology, and concerted efforts to expand our understanding to multiple race/ethnic groups, will be essential for constructing clinically relevant risk prediction models and develop effective strategies for disease prevention.

Epidemiology and Etiology of Leukemia and Lymphoma

Available evidence suggests that the incidence of leukemia and lymphoma tends to be higher in highly developed regions of the world and among Whites in the United States. Temporal trends in incidence are dynamic and multifactorial; for instance, the incidence of non-Hodgkin's lymphoma increased around the turn of the century, in part because of the acquired immune deficiency syndrome (AIDS) epidemic. Most leukemias and lymphomas are sporadic and the specific etiology remains elusive. Still, research shows that these malignancies often develop in the context of genetic abnormalities, immunosuppression, and exposure to risk factors like ionizing radiation, carcinogenic chemicals, and oncogenic viruses. The prognosis varies by subtype, with poorer survival outcomes for acute leukemias among adults, and more favorable outcomes for Hodgkin's lymphoma. At a time when specific prevention efforts targeting these malignancies are nonexistent, there is a great need to ensure equitable access to diagnostic services and treatments worldwide.

Hypercalcaemia, renal dysfunction, anaemia and bone lesions (CRAB) do not always represent multiple myeloma: diffuse large B cell lymphoma presenting with CRAB symptoms in a 69-year-old man

Hypercalcaemia, renal dysfunction, anaemia and bone lesions (CRAB) are a constellation of signs and symptoms that are collectively referred to as the CRAB features. When present together, multiple myeloma (MM) should be at the top of the differential diagnosis. We present a 69-year-old man who presented with severe body aches and bone pain in his ribs and pelvis, associated with fatigue and constipation. He was found to have hypercalcaemia, acute kidney injury, anaemia and numerous lytic lesion on chest imaging. Physical examination and imaging were unremarkable for any enlarged lymph nodes. The patient was initially suspected to have multiple myeloma, however, serum and urine protein electrophoresis, and serum free light chain assays were negative. The patient was ultimately diagnosed with diffuse large B cell lymphoma based on a bone marrow biopsy. This case highlights the fact that presence of hypercalcaemia, renal dysfunction, anaemia and bone lesions are not usually specific for MM.

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.

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.

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.

Investigation of spatio-temporal cancer clusters using residential histories in a case-control study of non-Hodgkin lymphoma in the United States

BACKGROUND

Non-Hodgkin lymphoma (NHL) is an enigmatic disease with few known risk factors. Spatio-temporal epidemiologic analyses have the potential to reveal patterns that may give clues to new risk factors worthy of investigation. We sought to investigate clusters of NHL through space and time based on life course residential histories.

METHODS

We used residential histories from a population-based NHL case-control study of 1300 cases and 1044 controls with recruitment centers in Iowa, Detroit, Seattle, and Los Angeles, and diagnosed in 1998-2000. Novel methods for cluster detection allowing for residential mobility, called Q-statistics, were used to quantify nearest neighbor relationships through space and time over the life course to identify cancer clusters. Analyses were performed on all cases together and on two subgroups of NHL: Diffuse large B-cell lymphoma and follicular lymphoma. These more homogenous subgroups of cases might have a more common etiology that could potentially be detected in cluster analysis. Based on simulation studies designed to help account for multiple testing across space and through time, we required at least four significant cases nearby one another to declare a region a potential cluster, along with confirmatory analyses using spatial-only scanning windows (SaTScan).

RESULTS

Evidence of a small cluster in southeastern Oakland County, MI was suggested using residences 10-18 years prior to diagnosis, and confirmed by SaTScan in a time-slice analysis 20 years prior to diagnosis, when all cases were included in the analysis. Consistent evidence of clusters was not seen in the two histologic subgroups.

CONCLUSIONS

Suggestive evidence of a small space-time cluster in southeastern Oakland County, MI was detected in this NHL case-control study in the USA.

Familial occurrence of chronic lymphocytic leukaemia in Norway

BACKGROUND

The only known risk factor for chronic lymphocytic leukaemia (CLL) is occurrence of the disease in close relatives. The aim of this study was to determine the frequency of familial chronic lymphocytic leukaemia.

MATERIAL AND METHOD

All patients with chronic lymphocytic leukaemia notified to the Cancer Registry in the period 1.10.2007-31.12.2009 were asked to report occurrences of malignant disease in siblings, parents, grandparents and children. The information about malignant haematological disease was verified with the Cancer Registry.

RESULTS

We found malignant haematological disease in close relatives of 42 of the 236 included patients (18%). CLL and lymphoma were the most common diagnoses. On average, 16 family members were identified in each family. The relative risk of developing CLL was six times higher in those who had close relatives with the disease (16 of a total of 3,776 family members) than among those who did not have close relatives who were affected (76 cases among 107,223 family members of 38,159 control subjects). The increased risk of disease was also associated with other lymphoproliferative diseases. With patrilinear, but not matrilinear inheritance, we found a birth order effect, with affection of younger men in a group of siblings, while the eldest escaped.

INTERPRETATION

Malignant haematological disease is common in the family members of patients with CLL. CLL is the most common disease, but there is extensive pleiotropy.

Etiology of Waldenström macroglobulinemia: genetic factors and immune-related conditions

Epidemiologic studies provide an insight into the etiology of lymphoplasmacytic lymphoma/Waldenström macroglobulinemia, which indicates that repetitive immune stimulation and genetic factors play an important role. Here, the current understanding on the causes of lymphoplasmacytic lymphoma/Waldenström macroglobulinemia are reviewed. Recent studies of the literature are discussed, and future population-based studies are proposed to further elucidate the molecular mechanisms that underlie these associations. Finally, the clinical implications of these data are outlined, and perspectives on clinical follow-up and counseling are provided.

Primary cutaneous large B-cell non-Hodgkin lymphoma in first-degree relatives

Primary cutaneous non-Hodgkin's lymphoma is a heterogeneous group of lymphoproliferative disorders characterized by indolent course, virtually exclusive skin involvement and the absence of systemic disease. We present two brothers, whose mother died of gastric diffuse large B-cell lymphoma, in whom in a period of 4 years primary cutaneous large B-cell non-Hodgkin lymphoma of the skin of the head was diagnosed. They were treated with immunochemotherapy according to R-CHOP protocol (rituximab and adriblastine, cyclophosphamide, oncovine and prednisone) achieving a complete remission. The possible etiological mechanism of this familial lymphoma occurrence is discussed.

Familial aggregation of lymphoplasmacytic lymphoma/Waldenström macroglobulinemia with solid tumors and myeloid malignancies

Lymphoplasmacytic lymphoma (LPL)/Waldenström macroglobulinemia (WM) is a B-cell disorder resulting from the accumulation, predominantly in the bone marrow, of clonally related lymphoplasmacytic cells. LPL/WM is a very rare disease, with an incidence rate of 3-4 cases per million people per year.Currently, the causes of LPL/WM are poorly understood; however, there are emerging data to support a role for immune-related factors in the pathogenesis of LPL/WM. In addition, data show that genetic factors are of importance in the etiology of LPL/WM. In this paper, we will review the current knowledge about familiality of LPL/WM and provide novel data on solid tumors and myeloid malignancies in first-degree relatives of LPL/WM patients.

What causes Waldenström's macroglobulinemia: genetic or immune-related factors, or a combination?

Population-based studies suggest a role for chronic immune stimulation and genetic factors in the causation of lymphoplasmacytic lymphoma (LPL)/Waldenström's macroglobulinemia (WM). In this review we summarize and discuss our current understanding on etiology and pathogenesis of LPL/WM. We also highlight on gaps in the literature and propose future directions for population-based and molecular studies designed to expand our knowledge and uncover biological underpinnings of identified associations. Further, we address clinical implications and provide perspective on the relevance of these data for patient counseling and clinical follow-up.

Prior history of non-melanoma skin cancer is associated with increased mortality in patients with chronic lymphocytic leukemia

We investigated whether a previous diagnosis of non-melanoma skin cancer among chronic lymphocytic leukemia patients is a predictor of poor outcome. Using the Swedish Cancer Registry, we conducted a population-based study to evaluate the survival patterns among chronic lymphocytic leukemia patients with and without non-melanoma skin cancer. Cox proportional hazards regression models were used and Kaplan-Meier curves were constructed. Of a total of 12,041 chronic lymphocytic leukemia cases identified, 236 cases, including 111 squamous cell cancer, had a prior history of non-melanoma skin cancer. Chronic lymphocytic leukemia patients with a prior history of non-melanoma skin cancer had a 1.29-fold (95% CI 1.10-1.52; p=0.0024) increased risk of dying; and those with a history of squamous cell cancer had a further elevated 1.86-fold (95% CI 1.46-2.36; p<0.0001) risk of dying. Kaplan-Meier plots showed that patients with a history of non-melanoma skin cancer, particularly those with squamous cell cancer, had significantly poorer survival than chronic lymphocytic leukemia patients without non-melanoma skin cancer (p<0.0001; log-rank test). Non-melanoma skin cancer may be a novel clinical predictor of worse chronic lymphocytic leukemia outcome.

Second malignancy risks after non-Hodgkin's lymphoma and chronic lymphocytic leukemia: differences by lymphoma subtype

PURPOSE

Previous studies have shown increased risks of second malignancies after non-Hodgkin's lymphoma (NHL) and chronic lymphocytic leukemia (CLL); however, no earlier investigation has quantified differences in risk of new malignancy by lymphoma subtype.

PATIENTS AND METHODS

We evaluated second cancer and leukemia risks among 43,145 1-year survivors of CLL/small lymphocytic lymphoma (SLL), diffuse large B-cell lymphoma (DLBCL), or follicular lymphoma (FL) from 11 Surveillance, Epidemiology, and End Results (SEER) population-based registries during 1992 to 2006.

RESULTS

Among patients without HIV/AIDS-related lymphoma, lung cancer risks were significantly elevated after CLL/SLL and FL but not after DLBCL (standardized incidence ratio [SIR], CLL/SLL = 1.42, FL = 1.28, DLBCL = 1.00; Poisson regression P for difference among subtypes, P(Diff) = .001). A similar pattern was observed for risk of cutaneous melanoma (SIR: CLL/SLL = 1.92, FL = 1.60, DLBCL = 1.06; P(Diff) = .004). Acute nonlymphocytic leukemia risks were significantly elevated after FL and DLBCL, particularly among patients receiving initial chemotherapy, but not after CLL/SLL (SIR: CLL/SLL = 1.13, FL = 5.96, DLBCL = 4.96; P(Diff) < .001). Patients with HIV/AIDS-related lymphoma (n = 932) were predominantly diagnosed with DLBCL and had significantly and substantially elevated risks for second anal cancer (SIR = 120.50) and Kaposi's sarcoma (SIR = 138.90).

CONCLUSION

Our findings suggest that differing immunologic alterations, treatments (eg, alkylating agent chemotherapy), genetic susceptibilities, and other risk factors (eg, viral infections, tobacco use) among lymphoma subtypes contribute to the patterns of second malignancy risk. Elucidating these patterns may provide etiologic clues to lymphoma as well as to the second malignancies.

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.

Familial chronic lymphocytic leukemia

PURPOSE OF REVIEW

Families with multiple individuals affected with chronic lymphocytic leukemia (CLL) and other related B-cell tumors have been described in the literature and strong familial aggregation has been seen in population studies. However, predisposing germline mutations have not been identified. We will discuss the spectrum of conditions associated with CLL in families and the advances in identifying the underlying susceptibility genes.

RECENT FINDINGS

Familial CLL does not appear to differ substantially from sporadic CLL in terms of prognostic markers and clinical outcome, although it may be associated with more indolent disease. The precursor condition, monoclonal B-cell lymphocytosis, also aggregates in CLL families. Linkage studies have been conducted in high-risk CLL families to screen the whole genome for susceptibility loci but no gene mutations have yet been identified by this method. Association studies of candidate genes have implicated several genes as being important in CLL but more studies are needed. Results from whole-genome association studies are promising.

SUMMARY

The ability to conduct large-scale genomic studies in unrelated CLL patients and in high-risk CLL families will play an important role in detecting susceptibility genes for CLL over the next few years and thereby help to delineate causal pathways.

Patterns of hematologic malignancies and solid tumors among 37,838 first-degree relatives of 13,896 patients with multiple myeloma in Sweden

There are emerging data to suggest a role for genetic factors in the pathogenesis of multiple myeloma (MM). Based on small numbers, certain solid tumors have been reported to occur more frequently among blood relatives of patients with MM. Using population-based data, we assessed risks for hematologic malignancies, monoclonal gammopathy of undetermined significance (MGUS), and solid tumors among first-degree relatives of patients with MM. We included 13,896 patients with MM and 54,365 matched controls. Also we identified first-degree relatives of patients with MM (n = 37,838) and controls (n = 151,068). Using a marginal survival model, we estimated relative risks (RRs) and 95% confidence intervals (CIs) for hematologic and solid tumors among family members of patients with MM and controls as measures of familial aggregation. Compared with relatives of controls, relatives of patients with MM had an increased risk of developing MM (RR = 2.1; 95% CI 1.6-2.9), MGUS (2.1; 1.5-3.1), acute lymphoblastic leukemia (ALL) (2.1; 1.0-4.2), any solid tumor (1.1; 1.0-1.1) and bladder cancer (1.3; 1.0-1.5). No significantly increased risk was found for other hematologic or solid malignancies. Our findings support a role for a shared susceptibility (genetic, environmental or both) that predisposes to MM, MGUS, ALL and bladder cancer.

Genetic and immune-related factors in the pathogenesis of lymphoproliferative and plasma cell malignancies

There are data to support a role for genetic and immune-related factors in the pathogenesis of lymphomas and plasma cell diseases. In this paper, we review our published large population-based studies and other relevant studies in Hodgkin's and non-Hodgkin's lymphomas, multiple myeloma, and the precursor condition monoclonal gammopathy of undetermined significance. We discuss the overlap in risk factors between related malignancies and explore the underlying mechanisms. Based on these studies, we provide clinical implications and discuss the relevance of these data for patient counseling and clinical follow-up. Finally, we suggest future directions for new studies designed to increase our current knowledge and to define underlying biological mechanisms of our findings.

Novel aspects pertaining to the relationship of Waldenström's macroglobulinemia, IgM monoclonal gammopathy of undetermined significance, polyclonal gammopathy, and hypoglobulinemia

Waldenström's macroglobulinemia (WM) is associated with a precursor condition, monoclonal gammopathy of undetermined significance (MGUS) of immunoglobulin-M (IgM) type. The etiology of these conditions is unknown. Recent studies at the population level have provided new data regarding familial aggregation of these disorders and other B-cell malignancies. Studies of familial clusters of WM have demonstrated an increased frequency of IgM MGUS compared with the general population and have provided new data suggesting that the phenotypic spectrum might also include polyclonal gammopathy and hypoglobulinemia. While the preponderance of immunoglobulin abnormalities in relatives of WM cases involves IgM, other immunoglobulin types (IgG and IgA) might also be affected. Large collaborative studies are needed to confirm these findings, which present an opportunity to define the earliest lesion(s) in the WM oncogenic pathway.

Common genetic variants in candidate genes and risk of familial lymphoid malignancies

Familial aggregation, linkage and case-control studies support the role of germline genes in the aetiology of lymphoid malignancies. To further examine the role of genetic variation underlying susceptibility, we analysed 1536 single nucleotide polymorphisms in 152 genes involved in apoptosis, DNA repair, immune response and oxidative stress pathways among a unique sample of 165 unrelated familial cases including patients with chronic lymphocytic leukaemia (CLL), Waldenström macroglobulinaemia (WM) and Hodgkin lymphoma (HL), and 107 spouse controls. We confirmed previous studies showing a polymorphism in the IL10 promoter (rs1800890/-3575T>A) to be associated with non-Hodgkin lymphoma, as this allele was found to be associated with both CLL and WM. We also confirmed the role of IL6 variation to be associated with HL. Polymorphisms in TNFSF10 were associated with both CLL and WM. Future replication and functional studies are needed to clarify the role of these genetic variants. Finally, our data further support the close association of WM and CLL.

Survival in non-Hodgkin's lymphoma by histology and family history

PURPOSE

Although survival has been studied for various subtypes of non-Hodgkin's lymphoma (NHL), there have been few comprehensive studies to quantify the prognosis, including all specific histologies. The effect of family history on survival in NHL has not been examined.

METHODS

We used the Swedish Family-Cancer Database to estimate hazard ratios in NHL by histology and family history.

RESULTS

Using diffuse centroblastic lymphoma as reference (HR 1.0), patients with Waldenström's macroglobulinemia and hairy-cell leukemia had the best survival. Survival advantage was also noted among patients with lymphoplasmacytic lymphoma and different kinds of follicular lymphomas. For T-cell lymphoma, mycosis fungoides showed a favorable prognosis. As for survival by family history, a total of 98 familial cases were noted in our Database with a similar prognosis compared to sporadic cases in both parental and offspring generations. A non-significant familial concordance of either good or poor survival was noted among family members when probands' prognosis was stratified by survival time.

CONCLUSIONS

Our results provide quantitative prognosis data for patients with NHL according to specific histologies. Patients with a familial NHL had a similar prognosis compared to patients with sporadic disease. The data suggest familial concordance in either good or poor survival among family members.

Highly increased familial risks for specific lymphoma subtypes

Studies have shown that familial risk contributes to aetiology of lymphomas. Using large population registries from Sweden, we evaluated risk of lymphoma subtypes among first-degree relatives of 2668 follicular lymphoma (FL) patients, 2517 diffuse large B-cell lymphoma (DLBCL) patients, and 6963 Hodgkin lymphoma (HL) patients compared to first-degree relatives of controls. Relatives were at the highest risk for developing the same lymphoma subtype as the case. DLBCL was increased 10-fold among relatives of DLBCL patients, FL was increased fourfold among relatives of FL patients and HL was increased fourfold among relatives of HL patients. These results imply that germline susceptibility genes are specific to lymphoma subtype.

Elevated risk of chronic lymphocytic leukemia and other indolent non-Hodgkin's lymphomas among relatives of patients with chronic lymphocytic leukemia

BACKGROUND

Previous studies have shown increased familial risk for chronic lymphocytic leukemia. In the most comprehensive study to date, we evaluated risk of chronic lymphocytic leukemia and lymphoproliferative disorders among first-degree relatives of chronic lymphocytic leukemia cases compared to first-degree relatives of controls.

DESIGN AND METHODS

Population-based registry data from Sweden were used to evaluate outcomes in 26,947 first-degree relatives of 9,717 chronic lymphocytic leukemia patients (diagnosed 1958-2004) compared with 107,223 first-degree relatives of 38,159 matched controls. Using a marginal survival model, we calculated relative risks (RR) and 95% confidence intervals as measures of familial aggregation.

RESULTS

Compared to relatives of controls, relatives of chronic lymphocytic leukemia patients had an increased risk for chronic lymphocytic leukemia (RR=8.5, 6.1-11.7) and other non-Hodgkin's lymphomas (NHLs) (RR=1.9, 1.5-2.3). Evaluating NHL subtypes, we found a striking excess of indolent B-cell NHL, specifically lymphoplasmacytic lymphoma/Waldenström macroglobulinemia and hairy cell leukemia. No excesses of aggressive B-cell or T-cell lymphomas were found. There was no statistical excess of Hodgkin's lymphoma, multiple myeloma, or the precursor condition, monoclonal gammopathy of undetermined significance, among chronic lymphocytic leukemia relatives.

CONCLUSIONS

These familial aggregations are striking and provide novel clues to research designed to uncover early pathogenetic mechanisms in chronic lymphocytic leukemia including studies to identify germ line susceptibility genes. However, clinicians should counsel their chronic lymphocytic leukemia patients emphasizing that because the baseline population risks are low, the absolute risk for a first-degree relative to develop chronic lymphocytic leukemia or another indolent lymphoma is low. At this time, an increased medical surveillance of first-degree relatives of chronic lymphocytic leukemia patients has no role outside research studies.

Genetics- and immune-related factors in the pathogenesis of lymphoplasmacytic lymphoma/ Waldenström's macroglobulinemia

There are emerging data to support a role for genetic and immune-related factors in the pathogenesis of lymphoplasmacytic lymphoma/Waldenström's macroglobulinemia. In this article, we review our recently published, large, population-based studies using data from Sweden and from United States veterans and propose mechanisms and pathways underlying our observations. We also discuss future directions for new studies designed to increase our current knowledge and to define underlying biologic mechanisms of our findings. Finally, based on novel insights on this topic, we discuss clinical implications and provide perspective on the relevance of these data for patient counseling and clinical follow-up.

Increased frequency of hematopoietic malignancies in relatives of patients with lymphoid neoplasms: a French case-control study

Lymphoid neoplasms (LNs), including non-Hodgkin's lymphoma (NHL), Hodgkin's lymphoma (HL), lymphoproliferative syndrome (LPS) and multiple myeloma (MM), are among the most frequent cancers ( approximately 17,000 new cases per year in France), after those related to smoking. LNs were investigated using the data from the ENGELA study. ENGELA is a multicenter hospital-based case-control study that was carried out in France over the period September 2000-December 2004. In all, 822 cases (397 NHL, 149 LH, 168 SLP and 108 MM) and 752 controls were included and described 5,481 and 5,188 first-degree relatives, respectively. A positive association with a familial history of hematopoietic cancer was observed for LN (OR = 1.7 [1.0-2.8]) overall and for LPS (OR = 3.2 [1.4-6.8]). The associations with HL (OR = 10.4 [2.0-53.8]) and NHL (OR = 2.4 [1.0-5.9]) were stronger for men. The associations were also stronger when the disease had been diagnosed before the relatives were aged 45 years. The results mainly support the involvement of genetic factors and suggest that at least some of those factors may be sex-linked. However, the slight overrepresentation of affected spouses among the cases might also support the responsibility of environmental factors.

Family history of haematopoietic malignancies and non-Hodgkin's lymphoma risk in the California Teachers Study

Family history of haematopoietic malignancies appears to be a risk factor for non-Hodgkin's lymphoma (NHL), but whether risk varies by family member's gender is unclear. Among 121 216 women participating in the prospective California Teachers Study, NHL risk varied by type of haematopoietic malignancy and gender of the relative.

Epidemiology, pathology and treatment of non-follicular indolent lymphomas

Non-follicular indolent subtypes of non-Hodgkin lymphoma (NHL), which include chronic lymphocytic leukemia, small lymphocytic lymphoma (SLL) and marginal zone lymphomas (MZL), are a diverse group of disorders with different presenting features, behaviour patterns and treatment outcomes. Current knowledge of these subtypes is largely based on retrospective analyses. A precise diagnosis can be difficult to achieve, and specific diagnostic criteria are needed to more precisely define some of the rarer indolent tumors, such as nodal and splenic MZLs. Although some subtypes of NHL have a prolonged indolent course, with a good prognosis (e.g. SLL), others (e.g. nodal and splenic MZLs) can rapidly evolve into more aggressive subtypes. In asymptomatic patients, treatment may be deferred until the disease progresses and the patient becomes symptomatic. Universally accepted therapeutic guidelines do not exist, however, and carefully designed, prospective clinical studies are needed to further assess optimal therapeutic approaches for these indolent NHLs.

Survival patterns among lymphoma patients with a family history of lymphoma

PURPOSE

Genetic factors are important in the etiology and pathogenesis of chronic lymphocytic leukemia (CLL), Hodgkin's lymphoma (HL), and non-Hodgkin's lymphoma (NHL). Only a few small studies have assessed clinical characteristics and prognosis for familial patients, with inconsistent findings.

METHODS

Using population-based registries from Sweden and Denmark, 7,749 patients with CLL, 7,476 patients with HL, and 25,801 patients with NHL with linkable first-degree relatives were identified. Kaplan-Meier curves were constructed to compare survival in patients with lymphoma with and without a family history of lymphoma. The risk of dying was assessed using adjusted Cox proportional hazard models.

RESULTS

We found 85 patients with CLL (1.10%), 95 patients with HL (1.28%), and 206 patients with NHL (0.80%) with a family history of any lymphoma. Five-year mortality was similar for patients with CLL (hazard ratio [HR], 1.28; 95% CI, 0.95 to 1.72), HL (HR, 0.78; 95% CI, 0.49 to 1.25), and NHL (HR, 0.91; 95% CI, 0.74 to 1.12) versus without a family history of any lymphoma. Mortality was also similar for patients with versus without a family history of the same lymphoma. T-cell/anaplastic lymphoma patients with a family history of NHL had poorer outcome 5-years after diagnosis (HR, 5.38; 95% CI, 1.65 to 17.52). Results were similar for 10 years of follow-up.

CONCLUSION

With the exception of T-cell/anaplastic lymphoma, survival patterns for patients with CLL, HL, and NHL with a family history of lymphoma were similar to those for sporadic patients, suggesting that most familial lymphomas do not have an altered clinical course. Our findings provide no evidence to modify therapeutic strategies for patients with CLL, HL, or NHL based solely on family history.

Multiple myeloma, chronic lymphocytic leukaemia and associated precursor diseases

Multiple myeloma and chronic lymphocytic leukaemia share common biological and clinical features including the presence of defined precursor conditions (monoclonal gammopathy of undetermined significance and monoclonal B-cell lymphocytosis respectively). Here, we discuss evidence from the literature on the potential aetiological roles for genetic and chronic immune stimulatory factors on the pathway from precursor to malignancy. Also, we speculate on the relationship between precursor and malignancy and talk about future directions and gaps in the literature.

Family studies in chronic lymphocytic leukaemia and other lymphoproliferative tumours

Families with multiple individuals affected with chronic lymphocytic leukaemia (CLL) and other related B-cell tumours have been described in the literature. Familial CLL does not appear to differ from sporadic CLL in terms of prognostic markers and clinical outcome. Large, population-based case-control and cohort studies have also shown significant familial aggregation of CLL and related conditions, including non-Hodgkin and Hodgkin lymphoma. Monoclonal B-cell lymphocytosis also aggregates in CLL families. However, the clinical implication of familial aggregation is minimal given the overall rarity of CLL. Linkage studies have been conducted in high-risk CLL families to screen the whole genome for loci that contribute to susceptibility but no gene mutations have yet been identified by this method. Association studies of candidate genes have implicated immune function and other genes but more studies are needed to verify these findings. The ability to conduct large scale genomic studies will play an important role in detecting susceptibility genes for CLL over the next few years and thereby help to delineate aetiological pathways.

Polymorphisms in xenobiotic-metabolizing genes and the risk of chronic lymphocytic leukemia and non-Hodgkin's lymphoma in adult Russian patients

Polymorphisms in genes coding xenobiotic-metabolizing enzymes are considered as risk factors modifying susceptibility to cancer. We developed a biochip for the analysis of 18 mutations in 10 genes of metabolizing system: CYP1A1, CYP2D6, GSTT1, GSTM1, MTHFR, MTRR, NQO1, CYP2C9, CYP2C19, and NAT2. Using allele-specific hybridization on the biochip 76 T-cell non-Hodgkin's lymphoma (NHL) patients, 83 B-cell chronic lymphocytic leukemia (B-CLL) patients, and 177 healthy donors were tested. Polymorphic CYP1A1 alleles were more frequent in B-CLL patients relative to normal controls, for example, a combination of polymorphic variants 4887C > A, 4889A > G, and 6235T > C (OR = 1.76, 95% CI = 1.0-3.1). The GSTM1 null genotype was more frequent in NHL patients relative to controls (OR = 1.82, 95% CI = 1.1-3.1). The combination of unfavorable polymorphic CYP1A1 variants and GSTM1 null genotype was found more frequently in B-CLL patients relative to controls (OR = 2.52, 95% CI = 1.3-4.9). In addition, male B-CLL patients demonstrated a significantly increased occurrence of heterozygous and homozygous allele *2 of CYP2C9 gene (OR = 2.38, 95% CI = 1.1-5.2) as well as a combination of alleles *2 and *3 of the gene (OR = 2.09, 95% CI = 1.1-3.9). Thus, our findings show the association between polymorphic alleles of CYP1A1, GSTM1, and CYP2C9 genes and the risk to develop NHL or B-CLL. The developed biochip can be considered as a convenient analytical tool for research studies and predictive analysis in oncohematology.

Genetic susceptibility to lymphoma

Genetic susceptibility studies of lymphoma may serve to identify at risk populations and clarify important disease mechanisms. This review considered all studies published through October 2006 on the contribution of genetic polymorphisms in the risk of lymphoma. Numerous studies implicate the role of genetic variants that promote B-cell survival and growth with increased risk of lymphoma. Several reports including a large pooled study by InterLymph, an international consortium of non-Hodgkin lymphoma (NHL) case-control studies, found positive associations between variant alleles in TNF -308G>A and IL10 -3575T>A genes and risk of diffuse large B-cell lymphoma. Four studies reported positive associations between a GSTT1 deletion and risk of Hodgkin and non-Hodgkin lymphoma. Genetic studies of folate-metabolizing genes implicate folate in NHL risk, but further studies that include folate and alcohol intakes are needed. Links between NHL and genes involved in energy regulation and hormone production and metabolism may provide insights into novel mechanisms implicating neuro- and endocrine-immune cross-talk with lymphomagenesis. However, this links will need replication in larger populations. Numerous studies suggest that common genetic variants with low penetrance influence lymphoma risk, though replication studies will be needed to eliminate false positive associations.

Long-term Evaluation of Three Multiple-Case Waldenström Macroglobulinemia Families

PURPOSE

Because the clinical significance of immunoglobulin abnormalities reported in relatives of familial Waldenström macroglobulinemia (WM) patients is unknown, we initiated a follow-up study of three WM families originally evaluated 27 years previously.

EXPERIMENTAL DESIGN

Of 29 eligible first-degree relatives of WM patients, 27 (93%) had originally participated in clinical and electrophoretic evaluations. We re-contacted all participants for prospective follow-up electrophoretic analysis and other studies.

RESULTS

Initially, five relatives had IgM monoclonal gammopathy (IgM MG), and four had IgM polyclonal gammopathy (PG). Twenty-two relatives (81%) were re-evaluated. Median follow-up was 17 years (range, 7-27). At re-contact, all IgM MG persisted or progressed, including three that evolved to WM. Among the four with PG, two new IgM MG cases developed. Overall, seven relatives (26%) had IgM MG, and five (18%) had IgM PG.

CONCLUSIONS

Although based on small numbers, this study provides the longest comprehensive follow-up of WM families to date. IgM MG seems to be a phenotypic marker of WM susceptibility in some families and may have a high risk of progression to WM. IgM PG may also be important in WM families. These observations require validation in larger studies and, if confirmed, may be used to identify a cohort (relatives with IgM MG) for future prevention strategies.

Family history of hematopoietic malignancies and risk of non-Hodgkin lymphoma (NHL): a pooled analysis of 10 211 cases and 11 905 controls from the International Lymphoma Epidemiology Consortium (InterLymph)

A role for genetic susceptibility in non-Hodgkin lymphoma (NHL) is supported by the accumulating evidence of common genetic variations altering NHL risk. However, the pattern of NHL heritability remains poorly understood. We conducted a pooled analysis of 10 211 NHL cases and 11 905 controls from the International Lymphoma Epidemiology Consortium (InterLymph) to evaluate NHL risk among those with hematopoietic malignancies in first-degree relatives. Odds ratios (ORs) and 95% confidence intervals (CIs) of NHL and its subtypes were estimated from unconditional logistic regression models with adjustment for confounders. NHL risk was elevated for individuals who reported first-degree relatives with NHL (OR = 1.5; 95% CI = 1.2-1.9), Hodgkin lymphoma (OR = 1.6; 95% CI = 1.1-2.3), and leukemia (OR = 1.4; 95% CI = 1.2-2.7). Risk was highest among individuals who reported a brother with NHL (OR = 2.8; 95% CI = 1.6-4.8) and was consistent for all NHL subtypes evaluated. If a first-degree relative had Hodgkin lymphoma, NHL risk was highest if the relative was a parent (OR = 1.7; 95% CI = 1.0-2.9). If a first-degree relative had leukemia, NHL risk was highest among women who reported a sister with leukemia (OR = 3.0; 95% CI = 1.6-5.6). The pattern of NHL heritability appeared to be uniform across NHL subtypes, but risk patterns differed by specific hematopoietic malignancies and the sex of the relative, revealing critical clues to disease etiology.

Non-Hodgkin's lymphoma as an exemplar of the effects of genetics and genomics

PURPOSE

To discuss the interface of genetics and genomics science in the identification and management of non-Hodgkin's lymphoma. The field of oncology is an exemplar of how the genomic revolution is influencing more individualized care and treatment of people with cancer and their families.

DESIGN

Integrated review of the cancer genetics and genomics literature.

METHODS

Published peer-reviewed research, conference proceedings, and peer-reviewed internet sites regarding the genetics and genomics of cancer and non-Hodgkin's lymphoma were reviewed, analyzed, and data synthesized.

FINDINGS

All malignancies have a genetic and genomic basis. Genetic and genomic break-throughs are rapidly being applied to all aspects of cancer care including: (a) identification of at-risk individuals before disease occurs, (b) diagnosis and characterization of disease and its aggressiveness when it appears via gene expression, (c) and individualization of therapies over the disease course based on these new molecular technologies.

CONCLUSIONS

Oncology nurses in every role, clinical subspecialty, and type of education are among the first nurses to integrate genetic and genomic information in such a broad context. This experience shows how genetic and genomic discoveries will interface with other health conditions and ultimately, will affect the practice of all nurses.

Familial CLL: Genes and Environment

Families with multiple individuals affected with chronic lymphocytic leukemia (CLL) and other related B-cell tumors have been described in the literature. Familial CLL does not appear to differ from sporadic CLL in terms of prognostic markers and clinical outcome. While some environmental factors (such as farming-related exposures and occupational chemicals) may increase risk of CLL, results of epidemiologic studies have been generally inconsistent. Rates of CLL in the population show significant international variation, with the highest rates in the U.S. and Europe and the lowest rates in Asia. Migrants from Asia to the U.S. also have low rates of CLL, which supports a greater role for genetic compared with environmental risk factors. Large, population-based case-control and cohort studies have also shown significant familial aggregation of CLL and related conditions including non-Hodgkin and Hodgkin lymphoma. Monoclonal B-cell lymphocytosis also aggregates in families with CLL. However, the clinical implication of familial aggregation is minimal given the overall rarity of CLL. Linkage studies have been conducted in high-risk CLL families to screen the whole genome for loci that contribute to susceptibility, but no gene mutations have yet been identified by this method. Association studies of candidate genes have implicated immune function and other genes, but more studies are needed to verify these findings. The ability to conduct large-scale genomic studies will play an important role in detecting susceptibility genes for CLL over the next few years and thereby help to delineate etiologic pathways.

Ascertainment and diagnostic accuracy for hematopoietic lymphoproliferative malignancies in Sweden 1964–2003

Population-based cancer registries are widely used to provide key information about cancer incidence, survival, determinants of progression and clues about pathogenesis. To substantially expand the limited data on diagnostic accuracy and completeness for lymphoproliferative (LP) tumors in such databases, we conducted a retrospective investigation of close to 1,000 cases diagnosed during 4 decades in Sweden. We identified and reviewed medical records for 494 LP tumor patients reported to the population-based Swedish Cancer registry and 503 LP tumor patients identified from hospitals in Sweden among patients with LP tumors diagnosed during 1964-2003. The stratified samples were randomly selected from patients according to LP subtype, over 4 equal calendar periods, and among 6 selected hospitals of diverse size and from different geographic regions. We found 97.9% of reported LP tumor cases to fulfill current diagnostic criteria for having an LP tumor and observed 89.7% to have accurate LP tumor subtype. The overall completeness of non-Hodgkin lymphoma, Hodgkin lymphoma and multiple myeloma cases in the Cancer registry was 95-99% but was lower for the more indolent tumors, chronic lymphocytic leukemia (87.9%) and Waldenström's macroglobulinemia (68.1%). We observed increased overall under-ascertainment for patients diagnosed above age 80 (27%) and among individuals diagnosed before 1973 (12%). In conclusion the diagnostic accuracy and completeness for classically defined LP tumor entities in the Swedish Cancer registry is high. However, we found under-ascertainment of patients with indolent LP tumors, particularly among patients diagnosed at older ages, with early-stage disease and diagnosed in earlier years.

Respiratory tract infections and subsequent risk of chronic lymphocytic leukemia

Recent evidence suggests that chronic lymphocytic leukemia (CLL) might occur following a response to an infectious agent. We conducted a population-based study including 4249 CLL patients diagnosed in Denmark from 1977 to 1997 and 15 690 frequency-matched controls to quantify risk of CLL following various airway infections. Through data linkage we gathered information on hospital inpatient/outpatient discharges that listed infections present at least 1 year prior to CLL. Using logistic regression, we calculated odds ratios (ORs) and 95% confidence intervals (CIs). Personal history of pneumonia was associated with significantly increased CLL risk (OR = 1.4; 1.2-1.8); risk was restricted to 1 to 4.99 years prior to CLL diagnosis (OR = 1.6; 1.2-2.0). Individuals with 3 or more prior pneumonia events had a significant 2.5-fold (1.1-5.6) elevated CLL risk, and risk increased with the number of pneumonia episodes (P(trend) < .001). None of 9 other respiratory-tract infections was significantly associated with CLL risk. Pneumonia might be a potential CLL trigger or it could represent premalignant immune disruption preceding CLL.

Genomewide linkage screen for Waldenstrom macroglobulinemia susceptibility loci in high-risk families

Waldenstrom macroglobulinemia (WM), a distinctive subtype of non-Hodgkin lymphoma that features overproduction of immunoglobulin M (IgM), clearly has a familial component; however, no susceptibility genes have yet been identified. We performed a genomewide linkage analysis in 11 high-risk families with WM that were informative for linkage, for a total of 122 individuals with DNA samples, including 34 patients with WM and 10 patients with IgM monoclonal gammopathy of undetermined significance (IgM MGUS). We genotyped 1,058 microsatellite markers (average spacing 3.5 cM), performed both nonparametric and parametric linkage analysis, and computed both two-point and multipoint linkage statistics. The strongest evidence of linkage was found on chromosomes 1q and 4q when patients with WM and with IgM MGUS were both considered affected; nonparametric linkage scores were 2.5 (P=.0089) and 3.1 (P=.004), respectively. Other locations suggestive of linkage were found on chromosomes 3 and 6. Results of two-locus linkage analysis were consistent with independent effects. The findings from this first linkage analysis of families at high risk for WM represent important progress toward identifying gene(s) that modulate susceptibility to WM and toward understanding its complex etiology.