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•Whole genome sequencing of 36 Hodgkin lymphoma (HL) families identifies 33 coding and 11 noncoding HL-risk variants.•Recurrent damaging variants are observed in known (KDR and KLHDC8B) and novel (PAX5, GATA3, and POLR1E) predisposing loci.

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.

Inherited loci have been found to be associated with risk of chronic lymphocytic leukemia (CLL). A combined polygenic risk score (PRS) of representative single nucleotide polymorphisms (SNPs) from these loci may improve risk prediction over individual SNPs. Herein, we evaluated the association of a PRS with CLL risk and its precursor, monoclonal B-cell lymphocytosis (MBL). We assessed its validity and discriminative ability in an independent sample and evaluated effect modification and confounding by family history (FH) of hematological cancers. For discovery, we pooled genotype data on 41 representative SNPs from 1499 CLL and 2459 controls from the InterLymph Consortium. For validation, we used data from 1267 controls from Mayo Clinic and 201 CLL, 95 MBL, and 144 controls with a FH of CLL from the Genetic Epidemiology of CLL Consortium. We used odds ratios (ORs) to estimate disease associations with PRS and c-statistics to assess discriminatory accuracy. In InterLymph, the continuous PRS was strongly associated with CLL risk (OR, 2.49; P= 4.4 × 10−94). We replicated these findings in the Genetic Epidemiology of CLL Consortium and Mayo controls (OR, 3.02; P= 7.8 × 10−30) and observed high discrimination (c-statistic = 0.78). When jointly modeled with FH, PRS retained its significance, along with FH status. Finally, we found a highly significant association of the continuous PRS with MBL risk (OR, 2.81; P= 9.8 × 10−16). In conclusion, our validated PRS was strongly associated with CLL risk, adding information beyond FH. The PRS provides a means of identifying those individuals at greater risk for CLL as well as those at increased risk of MBL, a condition that has potential clinical impact beyond CLL.

Inherited loci have been found to be associated with risk of chronic lymphocytic leukemia (CLL). A combined polygenic risk score (PRS) of representative single nucleotide polymorphisms (SNPs) from these loci may improve risk prediction over individual SNPs. Herein, we evaluated the association of a PRS with CLL risk and its precursor, monoclonal B-cell lymphocytosis (MBL). We assessed its validity and discriminative ability in an independent sample and evaluated effect modification and confounding by family history (FH) of hematological cancers. For discovery, we pooled genotype data on 41 representative SNPs from 1499 CLL and 2459 controls from the InterLymph Consortium. For validation, we used data from 1267 controls from Mayo Clinic and 201 CLL, 95 MBL, and 144 controls with a FH of CLL from the Genetic Epidemiology of CLL Consortium. We used odds ratios (ORs) to estimate disease associations with PRS and c-statistics to assess discriminatory accuracy. In InterLymph, the continuous PRS was strongly associated with CLL risk (OR, 2.49; P = 4.4 × 10−94). We replicated these findings in the Genetic Epidemiology of CLL Consortium and Mayo controls (OR, 3.02; P = 7.8 × 10−30) and observed high discrimination (c-statistic = 0.78). When jointly modeled with FH, PRS retained its significance, along with FH status. Finally, we found a highly significant association of the continuous PRS with MBL risk (OR, 2.81; P = 9.8 × 10−16). In conclusion, our validated PRS was strongly associated with CLL risk, adding information beyond FH. The PRS provides a means of identifying those individuals at greater risk for CLL as well as those at increased risk of MBL, a condition that has potential clinical impact beyond CLL.

Deletions on the long-arm of chromosome 20, del(20q), are common karyotypic abnormalities in myeloid disorders. Bioinformatic analyses of the B-allele frequency and log R ratio values from genome-wide association data have identified individuals who are mosaic for large structural abnormalities (>2 Mb). We investigated the most common autosomal event, namely mosaic del(20q), in 46?254 nonhematologic cancer cases and 36?229 cancer-free controls. We detected 91 mosaic del(20q) in leukocytes (80%) and buccal material (20%). The mosaic del(20q) mapped to a well-characterized minimally deleted region (MDR) reported in myeloid disorders. Common breakpoint clusters map to the coordinates of 29.9 to 31.5 Mb on the centromeric side of mosaic del(20q), and 42.0 to 45.4 Mb and 48.1 to 50.7 Mb on the telomeric end (GRCh36). Multivariate analyses suggest del(20q) increases with age, and is more common in males but less common in individuals of African ancestry. No conclusive associations were noted between the presence of mosaic del(20q) and subsequent solid tumor risk. Our observations demonstrate that the MDR of del(20q) is the most common large scale mosaic autosomal abnormality in whole blood and has a frequency of ~1 in every 1000 adults over the age of 50, which exceeds the expected incidence of myeloid leukemia in the population. Our results indicate that subclonal mosaic events of a region implicated in myeloid disorders on 20q are more frequent than the predicted population-estimated incidence of myeloid diseases, and thus suggest that these events can be tolerated until additional events accumulate that drive myeloid disorders.

Deletions on the long-arm of chromosome 20, del(20q), are common karyotypic abnormalities in myeloid disorders. Bioinformatic analyses of the B-allele frequency and log R ratio values from genome-wide association data have identified individuals who are mosaic for large structural abnormalities (>2 Mb). We investigated the most common autosomal event, namely mosaic del(20q), in 46 254 nonhematologic cancer cases and 36 229 cancer-free controls. We detected 91 mosaic del(20q) in leukocytes (80%) and buccal material (20%). The mosaic del(20q) mapped to a well-characterized minimally deleted region (MDR) reported in myeloid disorders. Common breakpoint clusters map to the coordinates of 29.9 to 31.5 Mb on the centromeric side of mosaic del(20q), and 42.0 to 45.4 Mb and 48.1 to 50.7 Mb on the telomeric end (GRCh36). Multivariate analyses suggest del(20q) increases with age, and is more common in males but less common in individuals of African ancestry. No conclusive associations were noted between the presence of mosaic del(20q) and subsequent solid tumor risk. Our observations demonstrate that the MDR of del(20q) is the most common large scale mosaic autosomal abnormality in whole blood and has a frequency of ∼1 in every 1000 adults over the age of 50, which exceeds the expected incidence of myeloid leukemia in the population. Our results indicate that subclonal mosaic events of a region implicated in myeloid disorders on 20q are more frequent than the predicted population-estimated incidence of myeloid diseases, and thus suggest that these events can be tolerated until additional events accumulate that drive myeloid disorders.

Loss of 13q14.3 is a chromosomal event found in ~50% of B-cell chronic lymphocytic leukemia (CLL) and monoclonal B-cell lymphocytosis (MBL) cases. Surveys of somatic alterations in solid tumors have shown sporadic 13q14.3 loss in many different tumor types, but not at high frequency in any specific tumor type. In our recent survey of the single-nucleotide polymorphism (SNP) microarray data from 127?000 cancer-free or solid tumor cases, we observed mosaic 13q14.3 loss as common autosomal somatic large structural events (>2?Mb in size) in blood and buccal-derived DNA. Herein, we examined this region more closely investigating structural mosaic events <2?Mb using SNP microarray data in 46?254 non-hematologic cancer cases and 36?229 controls. We detected 60 individuals with 13q14.3 mosaic loss, 1 mosaic copy neutral uniparental disomy and 13 individuals with homozygosity. Although 13q14.3 loss size was variable, the minimally deleted region (MDR) (chr13: 49?590?000–49?983?100; GRCh36) was comparable to what is classically reported in MBL and CLL. Breakpoint analysis of the estimated boundaries reveals enrichment for genes and open chromatin. The frequency of 13q14.3 loss significantly increases with increasing age (P-value=0.028), but was not significantly different between non-hematological cancer cases and controls (0.084% versus 0.058%; P-value=0.19). These findings suggest that mosaic 13q14.3 losses accumulate with age. Individuals with detected mosaic 13q14.3 deletions may be early, undetected cases of MBL or CLL, but not necessarily all will develop MBL and CLL.

In 728 Swedish cases of monoclonal gammopathy of undetermined significance (MGUS), followed up to 30 years (median, 10 years), we estimated the cumulative risk of hematologic disorders originating from lymphoid and myeloid lineages. Using Cox regression models, we examined associations of demographic and laboratory factors with progression and determined the discriminatory power of 3 prediction models for progression. Eighty-four MGUS cases developed a lymphoid disorder, representing a cumulative risk of 15.4%. Multiple myeloma (MM) occurred in 53 patients, and the 30-year cumulative risk was 10.6%; an ∼0.5% annual risk. Three factors were significantly associated with progression: abnormal free light-chain (FLC) ratio (<0.26 or >1.65), M-protein concentration (≥1.5 g/dL), and reduction of 1 or 2 noninvolved immunoglobulin isotype levels (immunoparesis). A prediction model with separate effects for these 3 factors and the M-protein isotype had higher discriminatory power than other models, although the differences were not statistically significant. The 30-year cumulative risk for myeloid malignancies was <2%. Our study confirms that abnormal FLC ratio and M-protein concentration >1.5 g/dL, factors previously considered by Mayo Clinic researchers, are predictors for MM progression and suggests that separate consideration of immunoparesis and the Mayo Clinic risk factors could improve identification of MGUS patients at high risk for progression.

In 728 Swedish cases of monoclonal gammopathy of undetermined significance (MGUS), followed up to 30 years (median, 10 years), we estimated the cumulative risk of hematologic disorders originating from lymphoid and myeloid lineages. Using Cox regression models, we examined associations of demographic and laboratory factors with progression and determined the discriminatory power of 3 prediction models for progression. Eighty-four MGUS cases developed a lymphoid disorder, representing a cumulative risk of 15.4%. Multiple myeloma (MM) occurred in 53 patients, and the 30-year cumulative risk was 10.6%; an ∼0.5% annual risk. Three factors were significantly associated with progression: abnormal free light-chain (FLC) ratio (<0.26 or >1.65), M-protein concentration (≥1.5 g/dL), and reduction of 1 or 2 noninvolved immunoglobulin isotype levels (immunoparesis). A prediction model with separate effects for these 3 factors and the M-protein isotype had higher discriminatory power than other models, although the differences were not statistically significant. The 30-year cumulative risk for myeloid malignancies was <2%. Our study confirms that abnormal FLC ratio and M-protein concentration >1.5 g/dL, factors previously considered by Mayo Clinic researchers, are predictors for MM progression and suggests that separate consideration of immunoparesis and the Mayo Clinic risk factors could improve identification of MGUS patients at high risk for progression.

Chronic lymphocytic leukemia (CLL) is the most common adult leukemia in the West and is an incurable malignancy. No firmly established evidence exists for environmental risk factors in the etiology of CLL. However, CLL is estimated to have one of the highest familial risks for a hematologic malignancy; this along with other evidence strongly supports an inherited genetic component. In the past 5 years, genome-wide association studies (GWAS) have provided the foundation for new avenues in the investigation of pathogenesis of this disease with 22 susceptibility loci currently identified. We review here the advances made in identifying these loci, the potential to translate these findings into clinical practice, and future directions needed to advance our understanding of the genetic susceptibility of CLL.

We performed a meta-analysis of 3 genome-wide association studies to identify additional common variants influencing chronic lymphocytic leukemia (CLL) risk. The discovery phase was composed of genome-wide association study data from 1121 cases and 3745 controls. Replication analysis was performed in 861 cases and 2033 controls. We identified a novel CLL risk locus at 6p21.33 (rs210142; intronic to the BAK1 gene, BCL2 antagonist killer 1; P = 9.47 × 10−16). A strong relationship between risk genotype and reduced BAK1 expression was shown in lymphoblastoid cell lines. This finding provides additional support for polygenic inheritance to CLL and provides further insight into the biologic basis of disease development.

We performed a meta-analysis of 3 genome-wide association studies to identify additional common variants influencing chronic lymphocytic leukemia (CLL) risk. The discovery phase was composed of genome-wide association study data from 1121 cases and 3745 controls. Replication analysis was performed in 861 cases and 2033 controls. We identified a novel CLL risk locus at 6p21.33 (rs210142; intronic to the BAK1gene, BCL2 antagonist killer 1; P= 9.47 × 10−16). A strong relationship between risk genotype and reduced BAK1expression was shown in lymphoblastoid cell lines. This finding provides additional support for polygenic inheritance to CLL and provides further insight into the biologic basis of disease development.

The associations between immune-related conditions and multiple myeloma (MM) and monoclonal gammopathy of undetermined significance (MGUS) have previously been investigated with inconsistent results. In a large population-based study, we identified 19 112 patients with MM, 5403 patients with MGUS, 96 617 matched control subjects, and 262 931 first-degree relatives. We calculated odds ratios (ORs) and 95% confidence intervals (CIs) for the association of MM and MGUS with immune-related conditions by use of logistic regression. A personal history of all infections combined was associated with a significantly increased risk of MM (OR = 1.2; 95% CI, 1.1-1.3), and a personal history of all conditions in the categories infections (OR = 1.6; 95% CI, 1.5-1.7), inflammatory conditions (OR = 1.4; 95% CI, 1.2-1.5), and autoimmune diseases (OR = 2.1; 95% CI, 1.9-2.4) was associated with a significantly increased risk of MGUS. Several specific immune-related conditions elevated the risk of MM and/or MGUS. A family history of autoimmune disease was associated with a significantly increased risk of MGUS (OR = 1.1; 95% CI, 1.00-1.2), but not MM. Our findings suggest that immune-related conditions and/or their treatment are of importance in the etiology of MGUS and possibly MM. The association of both personal and family history of autoimmune disease with MGUS indicates the potential for shared susceptibility for these conditions.

The associations between immune-related conditions and multiple myeloma (MM) and monoclonal gammopathy of undetermined significance (MGUS) have previously been investigated with inconsistent results. In a large population-based study, we identified 19 112 patients with MM, 5403 patients with MGUS, 96 617 matched control subjects, and 262 931 first-degree relatives. We calculated odds ratios (ORs) and 95% confidence intervals (CIs) for the association of MM and MGUS with immune-related conditions by use of logistic regression. A personal history of all infections combined was associated with a significantly increased risk of MM (OR = 1.2; 95% CI, 1.1-1.3), and a personal history of all conditions in the categories infections (OR = 1.6; 95% CI, 1.5-1.7), inflammatory conditions (OR = 1.4; 95% CI, 1.2-1.5), and autoimmune diseases (OR = 2.1; 95% CI, 1.9-2.4) was associated with a significantly increased risk of MGUS. Several specific immune-related conditions elevated the risk of MM and/or MGUS. A family history of autoimmune disease was associated with a significantly increased risk of MGUS (OR = 1.1; 95% CI, 1.00-1.2), but not MM. Our findings suggest that immune-related conditions and/or their treatment are of importance in the etiology of MGUS and possibly MM. The association of both personal and family history of autoimmune disease with MGUS indicates the potential for shared susceptibility for these conditions.

Using population-based data from Sweden, we identified all multiple myeloma (MM) patients (n = 8740) and 5652 monoclonal gammopathy of undetermined significance (MGUS) patients diagnosed between 1986 and 2005. We calculated standardized incidence rates (SIRs) for all subsequent hematologic and nonhematologic malignancies for MM patients diagnosed before/after 1995 (introduction of high-dose melphalan/autologous stem cell transplantation [HDM-ASCT]) and 2000 (introduction of immunomodulatory drugs [IMiDs]), respectively. MM patients had an 11.51-fold (95% confidence interval: 8.19-15.74) increased risk of acute myeloid leukemia (AML)/myelodysplastic syndromes (MDS); risk was very similar before/after 1995 and 2000, respectively. MGUS patients had an 8.01-fold (5.40-11.43) increased risk of AML/MDS. Risk was confined to IgG/IgA, while no IgM MGUS patients developed AML/MDS; patients with monoclonal-protein (M-protein) concentrations > 1.5 g/dL (SIR = 11.12; 3.61-25.96) had higher risk than those < 1.5 g/dL (SIR = 4.67; 1.71-10.16). An excess risk of nonmelanoma skin cancer was observed subsequent to both MM (SIR = 2.22; 1.74-2.80) and MGUS (SIR = 3.30; 2.76-3.90). Our novel observations of an excess risk for AML/MDS following IgG/IgA (but not IgM) MGUS, and the highest risk associated with M-protein concentrations > 1.5 g/dL, support a role for nontreatment-related factors in plasma cell dyscrasias. AML/MDS risk following MM was the same before/after the introduction of HDM-ASCT. Longer follow-up is needed to characterize second tumor risks in the IMiD era.

Prior genome-wide association (GWA) studies have identified 10 susceptibility loci for risk of chronic lymphocytic leukemia (CLL). To identify additional loci, we performed a GWA study in 407 CLL cases (of which 102 had a family history of CLL) and 296 controls. Moreover, given the strong familial risk of CLL, we further subset our GWA analysis to the CLL cases with a family history of CLL to identify loci specific to these familial CLL cases. Our top hits from these analyses were evaluated in an additional sample of 252 familial CLL cases and 965 controls. Using all available data, we identified and confirmed an independent association of 4 single-nucleotide polymorphisms (SNPs) that met genome-wide statistical significance within the IRF8 (interferon regulatory factor 8) gene (combined P values ≤ 3.37 × 10−8), located in the previously identified 16q24.1 locus. Subsetting to familial CLL cases, we identified and confirmed a new locus on chromosome 6p21.3 (combined P value = 6.92 × 10−9). This novel region harbors the HLA-DQA1 and HLA-DRB5 genes. Finally, we evaluated the 10 previously reported SNPs in the overall sample and replicated 8 of them. Our findings support the hypothesis that familial CLL cases have additional genetic variants not seen in sporadic CLL. Additional loci among familial CLL cases may be identified through larger studies.

Obesity and black race have been associated with excess risk of multiple myeloma. The association of obesity with monoclonal gammopathy of undetermined significance (MGUS) is unknown. Further, it is not known whether the increased risk of multiple myeloma and MGUS in blacks is related to socioeconomic status, genetic susceptibility, or both. We screened 1000 black and 996 white women (range, 40-79 years) of similar socioeconomic status for MGUS; the aim of the study was to assess MGUS risk in relation to obesity and race. A total of 39 (3.9%) blacks and 21 (2.1%) whites had MGUS. On multivariate analysis, obesity (odds ratio [OR] = 1.8; P= .04), black race (OR = 1.8; P= .04), and increasing age (> 55 vs < 43 years; OR = 2.5; P= .03) were independently associated with an excess risk of MGUS. Our findings support the hypothesis that obesity is etiologically linked to myelomagenesis. The 2-fold excess of MGUS among blacks compared with whites of similar socioeconomic status supports a role for susceptibility genes in MGUS.

Obesity and black race have been associated with excess risk of multiple myeloma. The association of obesity with monoclonal gammopathy of undetermined significance (MGUS) is unknown. Further, it is not known whether the increased risk of multiple myeloma and MGUS in blacks is related to socioeconomic status, genetic susceptibility, or both. We screened 1000 black and 996 white women (range, 40-79 years) of similar socioeconomic status for MGUS; the aim of the study was to assess MGUS risk in relation to obesity and race. A total of 39 (3.9%) blacks and 21 (2.1%) whites had MGUS. On multivariate analysis, obesity (odds ratio [OR] = 1.8; P = .04), black race (OR = 1.8; P = .04), and increasing age (> 55 vs < 43 years; OR = 2.5; P = .03) were independently associated with an excess risk of MGUS. Our findings support the hypothesis that obesity is etiologically linked to myelomagenesis. The 2-fold excess of MGUS among blacks compared with whites of similar socioeconomic status supports a role for susceptibility genes in MGUS.

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.

Patients with multiple myeloma (MM) have an increased risk of venous thrombosis. Interestingly, excess risk of venous thromboembolism has been observed among patients with monoclonal gammopathy of undetermined significance (MGUS). Using population-based data from Sweden, we assessed the risks of venous and arterial thrombosis in 18 627 MM and 5326 MGUS patients diagnosed from 1958 to 2006, compared with 70 991 and 20 161 matched controls, respectively. At 1, 5, and 10 years after MM diagnosis, there was an increased risk of venous thrombosis: hazard ratios (95% confidence intervals) were 7.5 (6.4-8.9), 4.6 (4.1-5.1), and 4.1 (3.8-4.5), respectively. The corresponding results for arterial thrombosis were 1.9 (1.8-2.1), 1.5 (1.4-1.6), and 1.5 (1.4-1.5). At 1, 5, and 10 years after MGUS diagnosis, hazard ratios were 3.4 (2.5-4.6), 2.1 (1.7-2.5), and 2.1 (1.8-2.4) for venous thrombosis. The corresponding risks for arterial thrombosis were 1.7 (1.5-1.9), 1.3 (1.2-1.4), and 1.3 (1.3-1.4). IgG/IgA (but not IgM) MGUS patients had increased risks for venous and arterial thrombosis. Risks for thrombosis did not vary by M-protein concentration (> 10.0 g/L or < 10.0 g/L) at diagnosis. MGUS patients with (vs without) thrombosis had no excess risk of MM or Waldenström macroglobulinemia. Our findings are of relevance for future studies and for improvement of thrombosis prophylaxis strategies.

Patients with multiple myeloma (MM) have an increased risk of venous thrombosis. Interestingly, excess risk of venous thromboembolism has been observed among patients with monoclonal gammopathy of undetermined significance (MGUS). Using population-based data from Sweden, we assessed the risks of venous and arterial thrombosis in 18 627 MM and 5326 MGUS patients diagnosed from 1958 to 2006, compared with 70 991 and 20 161 matched controls, respectively. At 1, 5, and 10 years after MM diagnosis, there was an increased risk of venous thrombosis: hazard ratios (95% confidence intervals) were 7.5 (6.4-8.9), 4.6 (4.1-5.1), and 4.1 (3.8-4.5), respectively. The corresponding results for arterial thrombosis were 1.9 (1.8-2.1), 1.5 (1.4-1.6), and 1.5 (1.4-1.5). At 1, 5, and 10 years after MGUS diagnosis, hazard ratios were 3.4 (2.5-4.6), 2.1 (1.7-2.5), and 2.1 (1.8-2.4) for venous thrombosis. The corresponding risks for arterial thrombosis were 1.7 (1.5-1.9), 1.3 (1.2-1.4), and 1.3 (1.3-1.4). IgG/IgA (but not IgM) MGUS patients had increased risks for venous and arterial thrombosis. Risks for thrombosis did not vary by M-protein concentration (> 10.0 g/L or < 10.0 g/L) at diagnosis. MGUS patients with (vs without) thrombosis had no excess risk of MM or Waldenström macroglobulinemia. Our findings are of relevance for future studies and for improvement of thrombosis prophylaxis strategies.

Monoclonal B Cell Lymphocytosis MBL refers to clones of CLLlike cells that exhibit CLL characteristics that fall short of the numbers required for CLL diagnosis. Data from large CLL kindreds document increased prevalence of MBL suggesting a genetic contribution to its etiology. The molecular features that favor progression of MBL to CLL are poorly understood but an elevated Bcell count is a risk factor for progression. An important consideration when evaluating volunteers from CLL families who are willing to donate bone marrow is that MBL be ruled out since the MBL donor clone could result in a second CLL in the recipient. Further studies of MBL are needed to identify the molecular features and how they evolve during progression. Published 2010 WileyLiss, Inc.

Familial clustering of the precursor condition, monoclonal gammopathy of undetermined significance (MGUS) has been observed in case reports and in smaller studies. Using population-based data from Sweden, we identified 4458 MGUS patients, 17505 population-based controls, and first-degree relatives of patients (n = 14621) and controls (n = 58387) with the aim to assess risk of MGUS and lymphoproliferative malignancies among first-degree relatives of MGUS patients. Compared with relatives of controls, relatives of MGUS patients had increased risk of MGUS (relative risk [RR] = 2.8; 1.4-5.6), multiple myeloma (MM; RR = 2.9; 1.9-4.3), lymphoplasmacytic lymphoma/Waldenström macroglobulinemia (LPL/WM; RR = 4.0; 1.5-11), and chronic lymphocytic leukemia (CLL; RR = 2.0; 1.2-2.3). Relatives of patients with IgG/IgA MGUS had a 4.0-fold (1.7-9.2), 2.9-fold (1.7-4.9), and 20-fold (2.3-170) elevated risk of developing MGUS, MM, and LPL/WM, respectively. Relatives of IgM MGUS patients had 5.0-fold (1.1-23) increased CLL risk and nonsignificant excess MM and LPL/WM risks. The results were very similar when we assessed risk by type of first-degree relative, age at MGUS (above/below 65 years), or sex. Risk of non-Hodgkin lymphoma or Hodgkin lymphoma was not increased among MGUS relatives. Among first-degree relatives of a nationwide MGUS cohort, we found elevated risks of MGUS, MM, LPL/WM, and CLL, supporting a role for germline susceptibility genes, shared environmental influences, or an interaction between both.

Familial clustering of the precursor condition, monoclonal gammopathy of undetermined significance (MGUS) has been observed in case reports and in smaller studies. Using population-based data from Sweden, we identified 4458 MGUS patients, 17505 population-based controls, and first-degree relatives of patients (n = 14621) and controls (n = 58387) with the aim to assess risk of MGUS and lymphoproliferative malignancies among first-degree relatives of MGUS patients. Compared with relatives of controls, relatives of MGUS patients had increased risk of MGUS (relative risk [RR] = 2.8; 1.4-5.6), multiple myeloma (MM; RR = 2.9; 1.9-4.3), lymphoplasmacytic lymphoma/Waldenström macroglobulinemia (LPL/WM; RR = 4.0; 1.5-11), and chronic lymphocytic leukemia (CLL; RR = 2.0; 1.2-2.3). Relatives of patients with IgG/IgA MGUS had a 4.0-fold (1.7-9.2), 2.9-fold (1.7-4.9), and 20-fold (2.3-170) elevated risk of developing MGUS, MM, and LPL/WM, respectively. Relatives of IgM MGUS patients had 5.0-fold (1.1-23) increased CLL risk and nonsignificant excess MM and LPL/WM risks. The results were very similar when we assessed risk by type of first-degree relative, age at MGUS (above/below 65 years), or sex. Risk of non-Hodgkin lymphoma or Hodgkin lymphoma was not increased among MGUS relatives. Among first-degree relatives of a nationwide MGUS cohort, we found elevated risks of MGUS, MM, LPL/WM, and CLL, supporting a role for germline susceptibility genes, shared environmental influences, or an interaction between both.

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.

A role for genetic factors in the etiology of lymphoplasmacytic lymphoma/Waldenström macroglobulinemia (LPL/WM) is implicated based on prior findings from multiply affected families and small case-control and cohort studies. We identified 2144 LPL/WM patients (1539 WM [72%] and 605 LPL [28%]) diagnosed in Sweden, 8279 population-based matched controls, and linkable first-degree relatives of patients (n = 6177) and controls (n = 24 609). Using a marginal survival model, we calculated relative risks and 95% confidence intervals as measures of familial aggregation. We found first-degree relatives of LPL/WM patients to have 20-fold (4.1-98.4), 3.0-fold (2.0-4.4), 3.4-fold (1.7-6.6), and 5.0-fold (1.3-18.9) increased risks of developing LPL/WM, non-Hodgkin lymphoma (NHL), chronic lymphocytic leukemia (CLL), and monoclonal gammopathy of undetermined significance (MGUS), respectively. However, there was no evidence of an increased risk of developing multiple myeloma or Hodgkin lymphoma. In analyses stratified by type of first-degree relative (parent, sibling, offspring), age at diagnosis of the probands (greater or less than 70 years), and sex of the first-degree relative, we did not observe the risk estimates to be significantly different compared with the overall analyses. Our findings of highly increased risks of developing LPL/WM, NHL, CLL, and MGUS support the operation of shared susceptibility genes that predispose to LPL/WM and other lymphoproliferative disorders.

A role for genetic factors in the etiology of lymphoplasmacytic lymphoma/Waldenström macroglobulinemia (LPL/WM) is implicated based on prior findings from multiply affected families and small case-control and cohort studies. We identified 2144 LPL/WM patients (1539 WM [72%] and 605 LPL [28%]) diagnosed in Sweden, 8279 population-based matched controls, and linkable first-degree relatives of patients (n = 6177) and controls (n = 24 609). Using a marginal survival model, we calculated relative risks and 95% confidence intervals as measures of familial aggregation. We found first-degree relatives of LPL/WM patients to have 20-fold (4.1-98.4), 3.0-fold (2.0-4.4), 3.4-fold (1.7-6.6), and 5.0-fold (1.3-18.9) increased risks of developing LPL/WM, non-Hodgkin lymphoma (NHL), chronic lymphocytic leukemia (CLL), and monoclonal gammopathy of undetermined significance (MGUS), respectively. However, there was no evidence of an increased risk of developing multiple myeloma or Hodgkin lymphoma. In analyses stratified by type of first-degree relative (parent, sibling, offspring), age at diagnosis of the probands (greater or less than 70 years), and sex of the first-degree relative, we did not observe the risk estimates to be significantly different compared with the overall analyses. Our findings of highly increased risks of developing LPL/WM, NHL, CLL, and MGUS support the operation of shared susceptibility genes that predispose to LPL/WM and other lymphoproliferative disorders.

Previous small studies have reported familial clustering of myeloproliferative neoplasms (MPNs), including polycythemia vera (PV), essential thrombocythemia (ET), and myelofibrosis (MF). We identified 6217 PV, 2838 ET, 1172 MF, and 812 MPN unclassifiable (NOS) patients diagnosed in Sweden, 43 550 controls, and first-degree relatives of cases (n = 24 577) and controls (n = 99 542). Using a marginal survival model, we calculated relative risks (RRs) and 95% confidence intervals as measures of familial aggregation. Relatives of MPN patients had significantly increased risks of PV (RR = 5.7; 3.5-9.1), ET (RR = 7.4; 3.7-14.8), and MPN NOS (RR = 7.5; 2.7-20.8). Analyses stratified by type of first-degree relative revealed consistently higher risks for siblings, compatible with a model of recessive genetic inheritance, which can be confirmed only by identifying the susceptibility gene(s). Mean age at MPN diagnosis was not different (P = .20) for affected relatives of cases (57.5 years) versus controls (60.6 years), and risk of MPN by age was not different for parents versus offspring of MPN cases (P = .10), providing no support for anticipation. Relatives of MPN patients had a borderline increased risk of chronic myeloid leukemia (CML; RR = 1.9; 0.9-3.8; P = .09). Our findings of 5- to 7-fold elevated risk of MPNs among first-degree relatives of MPN patients support the hypothesis that common, strong, shared susceptibility genes predispose to PV, ET, MF, and possibly CML.

Previous small studies have reported familial clustering of myeloproliferative neoplasms (MPNs), including polycythemia vera (PV), essential thrombocythemia (ET), and myelofibrosis (MF). We identified 6217 PV, 2838 ET, 1172 MF, and 812 MPN unclassifiable (NOS) patients diagnosed in Sweden, 43 550 controls, and first-degree relatives of cases (n = 24 577) and controls (n = 99 542). Using a marginal survival model, we calculated relative risks (RRs) and 95% confidence intervals as measures of familial aggregation. Relatives of MPN patients had significantly increased risks of PV (RR = 5.7; 3.5-9.1), ET (RR = 7.4; 3.7-14.8), and MPN NOS (RR = 7.5; 2.7-20.8). Analyses stratified by type of first-degree relative revealed consistently higher risks for siblings, compatible with a model of recessive genetic inheritance, which can be confirmed only by identifying the susceptibility gene(s). Mean age at MPN diagnosis was not different (P= .20) for affected relatives of cases (57.5 years) versus controls (60.6 years), and risk of MPN by age was not different for parents versus offspring of MPN cases (P= .10), providing no support for anticipation. Relatives of MPN patients had a borderline increased risk of chronic myeloid leukemia (CML; RR = 1.9; 0.9-3.8; P= .09). Our findings of 5- to 7-fold elevated risk of MPNs among first-degree relatives of MPN patients support the hypothesis that common, strong, shared susceptibility genes predispose to PV, ET, MF, and possibly CML.

BackgroundFamilial chronic lymphocytic leukemia CLL has the most frequent familial aggregation among hematological malignancies. Familial CLL families have been studied to identify susceptibility genes and other factors that contribute in the etiology of CLL. To date no study has been conducted to evaluate and compare patterns of cell surface antigen expression in familial CLL and sporadic CLL.MethodsThe pattern of cell surface antigen expression was studied in familial and sporadic CLL to determine if unique identifiers of familial CLL could be detected. Survival in familial CLL verses sporadic CLL was compared and the association between prognosis and CD38 expression studied.ResultsFamilial and sporadic CLL demonstrated the same characteristic immunophenotype positive for surface immunoglobulin, CD5, CD19, and CD23 with dim CD20, and CD22. CD2 and CD13 expression, however, were more frequent 30 of cases in familial CLL P 0.0003 for CD2, P 0.006 for CD13 than in sporadic CLL 2–6. There was no significant difference in survival in the two groups studied. Although the incidence of CD38 expression was similar in familial and sporadic CLL 47 and 44 respectively the association with prognosis differed. There was a trend to decreased survival in CD38 positive sporadic P 0.06 but not familial CLL patients.ConclusionsWe conclude that detection of CD2 or CD13 expression in CLL suggests familial CLL and examination of family history for additional affected members is warranted. Furthermore, CD38 expression does not carry the negative prognosis observed in sporadic CLL. Published 2008 WileyLiss, Inc.

Chronic lymphocytic leukemia (CLL) and other B-cell lymphoproliferative disorders display familial aggregation. To identify a susceptibility gene for CLL, we assembled families from the major European (ICLLC) and American (GEC) consortia to conduct a genome-wide linkage analysis of 101 new CLL pedigrees using a high-density single nucleotide polymorphism (SNP) array and combined the results with data from our previously reported analysis of 105 families. Here, we report on the combined analysis of the 206 families. Multipoint linkage analyses were undertaken using both nonparametric (model-free) and parametric (model-based) methods. After the removal of high linkage disequilibrium SNPs, we obtained a maximum nonparametric linkage (NPL) score of 3.02 (P = .001) on chromosome 2q21.2. The same genomic position also yielded the highest multipoint heterogeneity LOD (HLOD) score under a common recessive model of disease susceptibility (HLOD = 3.11; P = 7.7 × 10−5), which was significant at the genome-wide level. In addition, 2 other chromosomal positions, 6p22.1 (corresponding to the major histocompatibility locus) and 18q21.1, displayed HLOD scores higher than 2.1 (P < .002). None of the regions coincided with areas of common chromosomal abnormalities frequently observed in CLL. These findings provide direct evidence for Mendelian predisposition to CLL and evidence for the location of disease loci.

Chronic lymphocytic leukemia (CLL) and other B-cell lymphoproliferative disorders display familial aggregation. To identify a susceptibility gene for CLL, we assembled families from the major European (ICLLC) and American (GEC) consortia to conduct a genome-wide linkage analysis of 101 new CLL pedigrees using a high-density single nucleotide polymorphism (SNP) array and combined the results with data from our previously reported analysis of 105 families. Here, we report on the combined analysis of the 206 families. Multipoint linkage analyses were undertaken using both nonparametric (model-free) and parametric (model-based) methods. After the removal of high linkage disequilibrium SNPs, we obtained a maximum nonparametric linkage (NPL) score of 3.02 (P= .001) on chromosome 2q21.2. The same genomic position also yielded the highest multipoint heterogeneity LOD (HLOD) score under a common recessive model of disease susceptibility (HLOD = 3.11; P= 7.7 × 10−5), which was significant at the genome-wide level. In addition, 2 other chromosomal positions, 6p22.1 (corresponding to the major histocompatibility locus) and 18q21.1, displayed HLOD scores higher than 2.1 (P< .002). None of the regions coincided with areas of common chromosomal abnormalities frequently observed in CLL. These findings provide direct evidence for Mendelian predisposition to CLL and evidence for the location of disease loci.

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 (Ptrend < .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.

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 (Ptrend< .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.

Chronic lymphocytic leukemia (CLL) is the most prevalent form of leukemia in adults in western countries. A genome scan of CLL-prone families revealed a lod score of one in band 13q22.1. To investigate this finding, we selected 6 CLL families consisting of 63 individuals (CLL affected, n = 19; unaffected, n = 44) for fine mapping of a 23-megabase region in 13q14.2-q22.2. Interphase fluorescence in situ hybridization (FISH) revealed 13q14 deletion in 85% (11/13) of CLL patients. Four CLL families shared a 3.68-Mb minimal region in 13q21.33-q22.2. Two asymptomatic siblings who shared the 13q21.33-q22.2 at-risk haplotype exhibited CD5+ monoclonal B-cell lymphocytosis (MBL) on flow cytometry. One of these individuals also had a 13q14 deletion by FISH. These 2 individuals with MBL shared the at-risk haplotype with their CLL-affected relatives, providing further evidence of the relationship between CLL and MBL, as well as of the biologic significance of this novel region. Using direct DNA sequencing analysis, we screened 13 genes for mutations, but no frameshift or nonsense mutations were detected. Our studies revealed that 11 of the 13 genes in the candidate region were expressed in immune tissues, supporting their functional relevance in investigations of familial CLL. In conclusion, we identified a novel candidate region that may predispose to familial CLL.

Chronic lymphocytic leukemia (CLL) is the most prevalent form of leukemia in adults in western countries. A genome scan of CLL-prone families revealed a lod score of one in band 13q22.1. To investigate this finding, we selected 6 CLL families consisting of 63 individuals (CLL affected, n = 19; unaffected, n = 44) for fine mapping of a 23-megabase region in 13q14.2-q22.2. Interphase fluorescence in situ hybridization (FISH) revealed 13q14 deletion in 85% (11/13) of CLL patients. Four CLL families shared a 3.68-Mb minimal region in 13q21.33-q22.2. Two asymptomatic siblings who shared the 13q21.33-q22.2 at-risk haplotype exhibited CD5+monoclonal B-cell lymphocytosis (MBL) on flow cytometry. One of these individuals also had a 13q14 deletion by FISH. These 2 individuals with MBL shared the at-risk haplotype with their CLL-affected relatives, providing further evidence of the relationship between CLL and MBL, as well as of the biologic significance of this novel region. Using direct DNA sequencing analysis, we screened 13 genes for mutations, but no frameshift or nonsense mutations were detected. Our studies revealed that 11 of the 13 genes in the candidate region were expressed in immune tissues, supporting their functional relevance in investigations of familial CLL. In conclusion, we identified a novel candidate region that may predispose to familial CLL.

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.

A population-based case-control study was conducted to evaluate risk of developing chronic lymphocytic leukemia (CLL) associated with personal and/or family history of autoimmune and related diseases. Data were obtained for all (n = 7764) patients diagnosed with CLL in Sweden and Denmark over a 40-year period and with linkable relatives, 16 658 matched control subjects, and first-degree relatives of patients (n = 17 991) and control subjects (n = 39 388). Odds ratios (ORs) were calculated to quantify risk of CLL in relation to personal/family history of 32 autoimmune and related disorders. The risk of CLL was significantly increased among subjects with a personal history of pernicious anemia (OR = 1.94; 1.18-3.18), mainly in the 0- to 1-year latency period. A significantly decreased risk of CLL was found among individuals with a personal history of chronic rheumatic heart disease (OR = 0.55; 0.33-0.93), particularly persons with a long latency (10+ years) between the 2 conditions. We found no association between personal or familial occurrence of other autoimmune or related disorders and CLL. If our results are confirmed, mechanistic studies examining how pernicious anemia might promote increased occurrence of CLL and how chronic rheumatic heart disease protects against CLL, perhaps related to long-term antibiotics use, may provide insights to the as-yet-unknown etiology of CLL. (Blood. 2006;108:292-296)

A population-based case-control study was conducted to evaluate risk of developing chronic lymphocytic leukemia (CLL) associated with personal and/or family history of autoimmune and related diseases. Data were obtained for all (n = 7764) patients diagnosed with CLL in Sweden and Denmark over a 40-year period and with linkable relatives, 16 658 matched control subjects, and first-degree relatives of patients (n = 17 991) and control subjects (n = 39 388). Odds ratios (ORs) were calculated to quantify risk of CLL in relation to personal/family history of 32 autoimmune and related disorders. The risk of CLL was significantly increased among subjects with a personal history of pernicious anemia (OR = 1.94; 1.18-3.18), mainly in the 0- to 1-year latency period. A significantly decreased risk of CLL was found among individuals with a personal history of chronic rheumatic heart disease (OR = 0.55; 0.33-0.93), particularly persons with a long latency (10+ years) between the 2 conditions. We found no association between personal or familial occurrence of other autoimmune or related disorders and CLL. If our results are confirmed, mechanistic studies examining how pernicious anemia might promote increased occurrence of CLL and how chronic rheumatic heart disease protects against CLL, perhaps related to long-term antibiotics use, may provide insights to the as-yet-unknown etiology of CLL. (Blood. 2006;108:292-296)

The importance of genetic factors in etiology of chronic lymphocytic leukemia (CLL) is suggested by family and population studies. However, the spectrum of malignancies sharing common genetic factors with CLL and the effects of sex and age on familial risk are unknown. We used the Swedish Family-Cancer Database to test for increased familial risks of CLL and other lymphoproliferative tumors. Cancer diagnoses from 1958 to 1998 were assessed in 14 336 first-degree relatives of 5918 CLL cases and in 28 876 first-degree relatives of 11 778 controls. Cancer risks in relatives of cases were compared with those in relatives of controls using marginal survival models. Relatives of cases were at significantly increased risk for CLL (relative risk [RR] = 7.52; 95% confidence interval [CI], 3.63-15.56), for non-Hodgkin lymphoma (RR = 1.45; 95% CI, 0.98-2.16), and for Hodgkin lymphoma (RR = 2.35; 95% CI, 1.08-5.08). CLL risks were similar in parents, siblings, and offspring of cases, in male and female relatives, and were not affected by the case's age at diagnosis. Anticipation was not significant when analyzed using life table methods. We conclude that the familial component of CLL is shared with other lymphoproliferative malignances, suggesting common genetic pathways. However, because clinically diagnosed CLL is uncommon, absolute excess risk to relatives is small.

The importance of genetic factors in etiology of chronic lymphocytic leukemia (CLL) is suggested by family and population studies. However, the spectrum of malignancies sharing common genetic factors with CLL and the effects of sex and age on familial risk are unknown. We used the Swedish Family-Cancer Database to test for increased familial risks of CLL and other lymphoproliferative tumors. Cancer diagnoses from 1958 to 1998 were assessed in 14 336 first-degree relatives of 5918 CLL cases and in 28 876 first-degree relatives of 11 778 controls. Cancer risks in relatives of cases were compared with those in relatives of controls using marginal survival models. Relatives of cases were at significantly increased risk for CLL (relative risk [RR] = 7.52; 95% confidence interval [CI], 3.63-15.56), for non-Hodgkin lymphoma (RR = 1.45; 95% CI, 0.98-2.16), and for Hodgkin lymphoma (RR = 2.35; 95% CI, 1.08-5.08). CLL risks were similar in parents, siblings, and offspring of cases, in male and female relatives, and were not affected by the case's age at diagnosis. Anticipation was not significant when analyzed using life table methods. We conclude that the familial component of CLL is shared with other lymphoproliferative malignances, suggesting common genetic pathways. However, because clinically diagnosed CLL is uncommon, absolute excess risk to relatives is small.