Purpose

Apart from rare pedigrees with multiple cases of acute myeloid leukemia (AML), there is limited data on familial aggregation of AML and myelodysplastic syndromes (MDSs) in the population.

Patients and Methods

Swedish population-based registry data were used to evaluate risk of AML, MDS, and other malignancies among 24,573 first-degree relatives of 6,962 patients with AML and 1,388 patients with MDS compared with 106,224 first-degree relatives of matched controls. We used a marginal survival model to calculate familial aggregation.

Results

AML and/or MDS did not aggregate significantly in relatives of patients with AML. There was a modest risk ratio (RR, 1.3; 95% CI, 0.9 to 1.8) in myeloproliferative/myeloid malignancies combined. The risks for any hematologic or any solid tumor were modestly but significantly increased. Relatives of patients with MDS did not show an increased risk for any hematologic tumors. In contrast, we found a significantly increased risk (RR, 6.5; 95% CI, 1.1 to 38.0) of AML/MDS and of all myeloid malignancies combined (RR, 3.1; 95% CI, 1.0 to 9.8) among relatives of patients diagnosed at younger than age 21 years.

Conclusion

We did not find evidence for familial aggregation of the severe end of the spectrum of myeloid malignancies (AML and MDS). The risks of myeloproliferative neoplasms were modestly increased with trends toward significance, suggesting a possible role of inheritance. In contrast, although limited in sample size, relatives of young patients with AML were at increased risk of AML/MDS, suggesting that germline genes may play a stronger role in these patients. The increased risk of all hematologic malignancies and of solid tumors among relatives of patients with AML suggests that genes for malignancy in general and/or other environmental factors may be shared.

Purpose

Patients with acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS) often present with infections, but there are little data to assess whether a personal history of selected infections may act as pathogenic triggers. To additionally expand our knowledge on the role of immune stimulation in the causation of AML and MDS, we have conducted a large, population-based study to evaluate the risk of AML and MDS associated with a prior history of a broad range of infections or autoimmune diseases.

Patients and Methods

By using population-based central registries in Sweden, we included 9,219 patients with AML, 1,662 patients with MDS, and 42,878 matched controls. We used logistic regression to calculate odds ratios (ORs) and 95% CIs for the association of AML or MDS with infectious and/or autoimmune diseases.

Results

Overall, a history of any infectious disease was associated with a significantly increased risk of both AML (OR, 1.3; 95% CI, 1.2 to 1.4) and MDS (OR, 1.3; 95% CI, 1.1 to 1.5). These associations were significant even when we limited infections to those occurring 3 or more years before AML/MDS. A previous history of any autoimmune disease was associated with a 1.7-fold (95% CI, 1.5 to 1.9) increased risk for AML and 2.1-fold (95% CI, 1.7 to 2.6) increased risk for MDS. A large range of conditions were each significantly associated with AML and MDS.

Conclusion

Our novel findings indicate that chronic immune stimulation acts as a trigger for AML/MDS development. The underlying mechanisms may also be due to a common genetic predisposition or an effect of treatment for infections/autoimmune conditions.

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.

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 germ line 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 (MBL) 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 cases 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 etiologic pathways.

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 epidemiological studies have been generally inconsistent inconsistent and well-defined extrinsic risk factors are unknown. Large, population-based case-control and cohort studies have also shown significant familial aggregation of CLL and related conditions including non-Hodgkin lymphomas, especially other indolent lymphomas. The precursor condition, monoclonal B-cell lymphocytosis (MBL) also aggregates in CLL families. However because the baseline population risks for CLL and other indolent lymphomas are low, the absolute risk to a first-degree relative for developing CLL or a related disease is also low. 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 several genes as being important in CLL but more studies are needed to verify these findings. Results from whole genome association are promising. 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.

SUMMARY

Studies have shown that familial risk contributes to etiology 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 10-fold increased among relatives of DLBCL patients, FL was 4-fold increased among relatives of FL patients and HL was 4-fold increased among relatives of HL patients. These results imply that germline susceptibility genes are specific to lymphoma subtype.

For more than 50 years, links between autoimmunity and lymphomas have been described based on human and animal studies. Over the last three decades, many studies have addressed specific hypotheses about these associations using population level data. This has been accomplished by assessing previous autoimmune history in case-control studies of patients with lymphoma (mainly non-Hodgkin lymphoma) and myeloma, and by following cohorts of patients with various autoimmune diseases for subsequent development of lymphoma and multiple myeloma. In this paper, we review our recently published series of association studies based on data from Scandinavia and from U.S. Veterans as well as other relevant findings. We also discuss what these associations have revealed about the mechanisms and pathways underlying both autoimmunity and lymphoma. Finally, we discuss the future directions involving a combination of population and molecular studies that are needed to better define underlying biological mechanisms.

Purpose

Patients with myeloproliferative neoplasms (MPNs), including polycythemia vera, essential thrombocythemia, and primary myelofibrosis, have a propensity to develop acute myeloid leukemia (AML) and myelodysplastic syndromes (MDSs). Using population-based data from Sweden, we assessed the role of MPN treatment and subsequent AML/MDS risk with special focus on the leukemogenic potential of hydroxyurea (HU).

Methods

On the basis of a nationwide MPN cohort (N = 11,039), we conducted a nested case-control study, including 162 patients (153 and nine with subsequent AML and MDS diagnosis, respectively) and 242 matched controls. We obtained clinical and MPN treatment data for all patients. Using logistic regression, we calculated odds ratios (ORs) as measures of AML/MDS risk.

Results

Forty-one (25%) of 162 patients with MPNs with AML/MDS development were never exposed to alkylating agents, radioactive phosphorous (P32), or HU. Compared with patients with who were not exposed to HU, the ORs for 1 to 499 g, 500 to 999 g, more than 1,000 g of HU were 1.5 (95% CI, 0.6 to 2.4), 1.4 (95% CI, 0.6 to 3.4), and 1.3 (95% CI, 0.5 to 3.3), respectively, for AML/MDS development (not significant). Patients with MPNs who received P32 greater than 1,000 MBq and alkylators greater than 1 g had a 4.6-fold (95% CI, 2.1 to 9.8; P = .002) and 3.4-fold (95% CI, 1.1 to 10.6; P = .015) increased risk of AML/MDS, respectively. Patients receiving two or more cytoreductive treatments had a 2.9-fold (95% CI, 1.4 to 5.9) increased risk of transformation.

Conclusion

The risk of AML/MDS development after MPN diagnosis was significantly associated with high exposures of P32 and alkylators but not with HU treatment. Twenty-five percent of patients with MPNs who developed AML/MDS were not exposed to cytotoxic therapy, supporting a major role for nontreatment-related factors.

Background

Celiac disease (CD), a common digestive disease, is well-known to be associated with excess non-Hodgkin lymphoma (NHL) risk. However, there are only limited data on risk in the current era of serologic testing and human leukocytes antigen (HLA) typing to screen for CD. Also, there is no information on the role of family history of CD in relation to lymphoma risk.

Methods

We identified 37,869 NHL, 8323 Hodgkin lymphoma (HL), 13,842 chronic lymphocytic leukemia (CLL) patients diagnosed in Sweden 1965-2004, 236,408 matched controls, and 613,961 first-degree relatives. Using logistic regression, we calculated odds ratios (ORs) and 95% confidence intervals (CIs) as measures of risks adjusted for matching factors.

Results

Overall we found persons with a hospital discharge diagnosis of CD to have a 5.35-fold (95%CI=3.56-8.06) increased NHL risk. Risk of HL was borderline increased (OR=2.54, 95%CI=0.99-6.56); however, there was no excess CLL risk. Persons diagnosed with CD in 1975-1984, 1985-1994, and 1995-2004 had a 13.2-fold (95%CI=3.63-48.0), 7.90-fold (95%CI=3.38-18.5), and 3.84-fold (95%CI=2.28-6.45) increased risk of NHL, respectively (Ptrend<0.0001). Individuals with a sibling affected with CD had a 2.03-fold (95%CI=1.29-3.19) increased NHL risk.

Conclusions

Persons with CD have an increased NHL risk; however, the excess risk has tapered off substantially in the last four decades. The observed excess NHL risk among individuals with a sibling affected with CD suggests shared susceptibility. Future studies are needed to explore the roles of gluten intake, secondary intestinal inflammation, and susceptibility genes in relation to subsequent risk of developing lymphoma.

Summary

Monoclonal B-cell lymphocytosis (MBL) is an asymptomatic haematological condition characterized by low absolute levels of B-cell clones with a surface immunophenotype similar to that of chronic lymphocytic leukaemia (CLL). In the general population, MBL increases with age with a prevalence of 5–9% in individuals over age 60 years. It has been reported to be higher among first-degree relatives from CLL families. We report results of multi-parameter flow cytometry among 505 first-degree relatives with no personal history of lymphoproliferative disease from 140 families having at least two cases of CLL. Seventeen percent of relatives had MBL. Age was the most important determinant where the probability for developing MBL by age 90 years was 61%. MBL clustered in certain families but clustering was independent of the number of known CLL cases in a family. As is the case with CLL, males had a significantly higher risk for MBL than did females (p=0.04). MBL patients had significantly higher mean absolute lymphocyte counts (2.4 × 109/l) and B-cell counts (0.53 × 109/l) than those with a normal B-cell immunophenotype. Our findings show that MBL occurs at a very high rate in high risk CLL families. Both the age and gender distribution of MBL are parallel to CLL, implying a shared inherited risk.

Background

Chronic immune stimulation appears to be associated with lymphoplasmacytic lymphoma (LPL)-Waldenström macroglobulinemia (WM); however, available information is sparse. We conducted, to our knowledge, the most comprehensive study to date to evaluate associations between a personal or family history of many immune-related and/or inflammatory disorders and the subsequent risk of LPL-WM.

Methods

We used Swedish population-based registries to identify 2470 case patients with LPL-WM, 9698 matched control subjects, and almost 30 000 first-degree relatives of either case patients or control subjects. We evaluated a wide range of autoimmune, infectious, allergic, and inflammatory conditions. We calculated odds ratios (ORs) and 95% confidence intervals (CIs) for each condition by use of logistic regression.

Results

An increased risk of LPL-WM was associated with a personal history of the following autoimmune diseases: systemic sclerosis (OR = 4.7, 95% CI = 1.4 to 15.3), Sjögren syndrome (OR = 12.1, 95% CI = 3.3 to 45.0), autoimmune hemolytic anemia (OR = 24.2, 95% CI = 5.4 to 108.2), polymyalgia rheumatica (OR = 2.9, 95% CI = 1.6 to 5.2), and giant cell arteritis (OR = 8.3, 95% CI = 2.1 to 33.1). An increased risk of LPL-WM was associated with a personal history of the following infectious diseases: pneumonia (OR = 1.4, 95% CI = 1.1 to 1.7), septicemia (OR = 2.4, 95% CI = 1.2 to 4.3), pyelonephritis (OR = 1.7, 95% CI = 1.1 to 2.5), sinusitis (OR = 2.7, 95% CI = 1.4 to 4.9), herpes zoster (OR = 3.4, 95% CI = 2.0 to 5.6), and influenza (OR = 2.9, 95% CI = 1.7 to 5.0). An increased risk of LPL-WM was associated with a family history of the following autoimmune or infectious diseases: Sjögren syndrome (OR = 5.0, 95% CI = 2.1 to 12.0), autoimmune hemolytic anemia (OR = 3.8, 95% CI = 1.1 to 13.2), Guillain–Barré syndrome (OR = 4.1, 95% CI = 1.8 to 9.4), cytomegalovirus (OR = 2.7, 95% CI = 1.4 to 5.3), gingivitis and periodontitis (OR = 1.9, 95% CI = 1.3 to 2.7), and chronic prostatitis (OR = 4.3, 95% CI = 1.7 to 11.1).

Conclusions

Personal history of certain immune-related and/or infectious conditions was strongly associated with increased risk of LPL-WM. The association of both personal and family history of Sjögren syndrome and autoimmune hemolytic anemia with risk of LPL-WM indicates the potential for shared susceptibility for these conditions.

Background

There is strong and consistent evidence that a genetic component contributes to the etiology of chronic lymphocytic leukemia (CLL). A recent genome-wide association study (GWAS) of CLL identified 7 genetic variants that increased the risk of CLL within a European population.

Methods

We evaluated the association of these variants, or variants in linkage disequilibrium (LD) with these variants, with CLL risk in an independent sample of 438 CLL cases and 328 controls.

Results

Of these 7 SNPs, 6 had p-trend < 0.05 and had estimated odds ratios (ORs) that were strikingly comparable to those of the previous study. Associations were seen for rs9378805 (OR = 1.47, 95% CI: 1.19, 1.80, p-trend = 0.0003) near IRF4 and rs735665 near GRAMD1B (OR= 1.47; 95% CI: 1.14, 1.89; p-trend = 0.003). However, no associations (P> 0.05) were found for rs11083846, nor were any found for any SNPs in LD with rs11083846.

Conclusions

Our results confirm the previous findings and further support the role of a genetic basis in the etiology of CLL; however, more research is needed to elucidate the causal SNP(s) and the potential manner in which these SNPs or linked SNPs function in CLL pathogenesis.

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 MM patients. Using population-based data, we assessed risks for hematologic malignancies, monoclonal gammopathy of undetermined significance (MGUS), and solid tumors among first-degree relatives of MM patients. We included 13,896 MM patients and 54,365 matched controls. Also we identified first-degree relatives of MM patients (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 MM patients and controls as measures of familial aggregation. Compared to relatives of controls, relatives of MM patients 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.

Summary

Familial aggregation, linkage, and case-control studies support the role of germline genes in the etiology of lymphoid malignancies. To further examine the role of genetic variation underlying susceptibility, we analyzed 1536 SNPs 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 leukemia (CLL), Waldenström's (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 since we found this allele to be associated with both CLL and WM. We also confirmed the role of IL6 variation to be associated with HL. Polymorphisms in the TRAIL gene 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.

Myeloproliferative neoplasms (MPNs) are a group of closely related stem-cell-derived clonal proliferative diseases. Most cases are sporadic but first-degree relatives of MPN patients have a five- to seven-fold increased risk for developing an MPN. The tumors of most patients carry a mutation in the Janus kinase 2 gene (JAK2V617F). Recently, three groups have described a strong association of JAK2 germline polymorphisms with MPN in patients positive for JAK2V617F. The somatic mutation occurs primarily on one particular germline JAK2 haplotype, which may account for as much as 50% of the risk to first-degree relatives. This finding provides new directions for unraveling the pathogenesis of MPN.

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 paper, we review our recently published large population-based studies using data from Sweden and from U.S. Veterans and proposed mechanisms and pathways underlying our observations. We also talk about future directions for new studies designed to increase our current knowledge and to define underlying biological 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.

Risk factors for testicular germ cell tumors (TGCT) have not been well-identified, however, data suggest that risks of cancer in family members of men with TGCT is elevated. Using family history data from 738 cases and 904 controls enrolled in the U.S. Servicemen's Testicular Tumor Environmental and Endocrine Determinants (STEED) Study from 2002−2005, the risk of cancer in first- and second-degree family members of these men was examined. Relative risks (RR) and 95% confidence intervals (CI) were estimated using Cox proportional hazards models, adjusting for reference age of case or control, race/ethnicity of case or control, sex of family member, and lineage (maternal versus paternal). An increased risk of all cancer among first-degree relatives of cases compared to controls was observed (RR=1.17, 95% CI, 1.01−1.35). There were suggestions of differences in risk when stratifying all relatives by lineage. For maternal relatives, there was a statistically significant increased risk of all cancer (RR=1.16, 95% CI, 1.04−1.30), digestive tract (RR=1.52, 95% CI, 1.15−2.00), and male genital organ cancer (RR=1.70, 95% CI, 1.15−2.51); there was also a suggestion of increased risks of hematopoetic cancers, cancers in the female genital organs, and non-melanoma skin cancer. For paternal relatives, there was a statistically significant association only with decreased risk of lung cancer (RR=0.69, 95% CI, 0.51−0.94). Thus, this study suggests that there may be aggregation of cancer among families of men diagnosed with TGCT.

Although several genes (including a strong effect in the human leukocyte antigen (HLA) region) and some environmental factors have been implicated to cause susceptibility to rheumatoid arthritis (RA), the etiology of the disease is not completely understood. The ability to screen the entire genome for association to complex diseases has great potential for identifying gene effects. However, the efficiency of gene detection in this situation may be improved by methods specifically designed for high-dimensional data. The aim of this study was to compare how three different statistical approaches, multifactor dimensionality reduction (MDR), random forests (RF), and an omnibus approach, worked in identifying gene effects (including gene-gene interaction) associated with RA. We developed a test set of genes based on previous linkage and association findings and tested all three methods. In the presence of the HLA shared-epitope factor, other genes showed weaker effects. All three methods detected SNPs in PTPN22 and TRAF1-C5 as being important. But we did not detect any new genes in this study. We conclude that the three high-dimensional methods are useful as an initial screening for gene associations to identify promising genes for further modeling and additional replication studies.

Polymorphisms in genes coding for enzymes that activate tobacco lung carcinogens may generate inter-individual differences in lung cancer risk. Previous studies had limited sample sizes, poor exposure characterization, and a few single nucleotide polymorphisms (SNPs) tested in candidate genes. We analyzed 25 SNPs (some previously untested) in 2101 primary lung cancer cases and 2120 population controls from the Environment And Genetics in Lung cancer Etiology (EAGLE) study from six phase I metabolic genes, including cytochrome P450s, microsomal epoxide hydrolase, and myeloperoxidase. We evaluated the main genotype effects and genotype-smoking interactions in lung cancer risk overall and in the major histology subtypes. We tested the combined effect of multiple SNPs on lung cancer risk and on gene expression. Findings were prioritized based on significance thresholds and consistency across different analyses, and accounted for multiple testing and prior knowledge. Two haplotypes in EPHX1 were significantly associated with lung cancer risk in the overall population. In addition, CYP1B1 and CYP2A6 polymorphisms were inversely associated with adenocarcinoma and squamous cell carcinoma risk, respectively. Moreover, the association between CYP1A1 rs2606345 genotype and lung cancer was significantly modified by intensity of cigarette smoking, suggesting an underling dose-response mechanism. Finally, increasing number of variants at CYP1A1/A2 genes revealed significant protection in never smokers and risk in ever smokers. Results were supported by differential gene expression in non-tumor lung tissue samples with down-regulation of CYP1A1 in never smokers and up-regulation in smokers from CYP1A1/A2 SNPs. The significant haplotype associations emphasize that the effect of multiple SNPs may be important despite null single SNP-associations, and warrants consideration in genome-wide association studies (GWAS). Our findings emphasize the necessity of post-GWAS fine mapping and SNP functional assessment to further elucidate cancer risk associations.

Rheumatoid arthritis is a clinically and genetically heterogeneous disease. Anti-cyclic citrullinated (anti-CCP) antibodies have a high specificity for rheumatoid arthritis and levels correlate with disease severity. The focus of this study was to examine whether analyzing anti-CCP levels could increase the power of linkage analysis by identifying a more homogeneous subset of rheumatoid arthritis patients. We also wanted to compare linkage signals when analyzing anti-CCP levels as dichotomized (CCP_binary), categorical (CCP_cat), and continuous traits, with and without transformation (log_CCP and CCP_cont). Illumina single-nucleotide polymorphism scans of the North American Rheumatoid Arthritis Consortium families were analyzed for four chromosomes (6, 7, 11, 22) using nonparametric linkage (NPL) (rheumatoid arthritis and CCP_binary), regress (CCP_cat and Log_CCP), and deviates (CCP_cont) analysis options as implemented in Merlin. Similar linkage results were obtained from analyses of rheumatoid arthritis, CCP_binary, and CCP_cont. The only exception was that we observed improved linkage signals and a narrower region for CCP_binary as compared to a clinical diagnosis of rheumatoid arthritis alone on chromosome 7, a region which previously showed variation in linkage results with rheumatoid arthritis according to anti-CCP levels. Analyses of CCP_cat and Log_CCP had little power to detect linkage. Our data suggested that linkage analyses of anti-CCP levels may facilitate identification of rheumatoid arthritis genes but quantitative analyses did not further improve power. Our study also highlighted that quantitative trait linkage results are highly sensitive to phenotype transformation and analytic approaches.

Although current methods in genetic epidemiology have been extremely successful in identifying genetic loci responsible for Mendelian traits, most common diseases do not follow simple Mendelian modes of inheritance. It is important to consider how our current methodologies function in the realm of complex diseases. The aim of this study was to determine the ability of conventional association methods to fine map a locus of interest. Six study populations were selected from 10 replicates (New York) from the Genetic Analysis Workshop 14 simulated dataset and analyzed for association between the disease trait and locus D2. Genotypes from 45 single-nucleotide polymorphisms in the telomeric region of chromosome 3 were analyzed by Pearson's chi-square tests for independence to test for association with the disease trait of interest. A significant association was detected within the region; however, it was found 3 cM from the documented location of the D2 disease locus. This result was most likely due to the method used for data simulation. In general, this study showed that conventional case-control association methods could detect disease loci responsible for the development of complex traits.

Recent studies have suggested that a high-density single nucleotide polymorphism (SNP) marker set could provide equivalent or even superior information compared with currently used microsatellite (STR) marker sets for gene mapping by linkage. The focus of this study was to compare results obtained from linkage analyses involving extended pedigrees with STR and single-nucleotide polymorphism (SNP) marker sets. We also wanted to compare the performance of current linkage programs in the presence of high marker density and extended pedigree structures. One replicate of the Genetic Analysis Workshop 14 (GAW14) simulated extended pedigrees (n = 50) from New York City was analyzed to identify the major gene D2. Four marker sets with varying information content and density on chromosome 3 (STR [7.5 cM]; SNP [3 cM, 1 cM, 0.3 cM]) were analyzed to detect two traits, the original affection status, and a redefined trait more closely correlated with D2. Multipoint parametric and nonparametric linkage analyses (NPL) were performed using programs GENEHUNTER, MERLIN, SIMWALK2, and S.A.G.E. SIBPAL. Our results suggested that the densest SNP map (0.3 cM) had the greatest power to detect linkage for the original trait (genetic heterogeneity), with the highest LOD score/NPL score and mapping precision. However, no significant improvement in linkage signals was observed with the densest SNP map compared with STR or SNP-1 cM maps for the redefined affection status (genetic homogeneity), possibly due to the extremely high information contents for all maps. Finally, our results suggested that each linkage program had limitations in handling the large, complex pedigrees as well as a high-density SNP marker set.

Background

Pedigree, demographic, square-root transformed maximum alcohol (SRMAXAPD) and maximum cigarette (MAXCPD) consumption, and genome-wide scan data from the Framingham Heart Study (FHS) were used to investigate genetic factors that may affect alcohol and cigarette consumption in this population-based sample.

Results

A significant sister:sister correlation greater than spouse correlation was observed for MAXCPD only. Single-point sib-pair regression analysis provided nominal evidence for linkage of loci to both SRMAXAPD and MAXCPD consumption traits, with more significant evidence of linkage to SRMAXAPD than to MAXCPD. One genomic region, chr9q21.11, exhibits significant multi-point sib-pair regression to SRMAXAPD.

Conclusion

SRMAXAPD exhibits greater evidence for genetic linkage than does MAXCPD in the FHS sample. Four regions of the genome exhibiting nominal evidence for linkage to SRMAXAPD in the FHS sample correspond to regions of the genome previously identified as linked to alcoholism or related traits in the family data set ascertained on individuals affected with alcohol dependence known as COGA.

Clonal mosaicism for large chromosomal anomalies (duplications, deletions and uniparental disomy) was detected using SNP microarray data from over 50,000 subjects recruited for genome-wide association studies. This detection method requires a relatively high frequency of cells (>5–10%) with the same abnormal karyotype (presumably of clonal origin) in the presence of normal cells. The frequency of detectable clonal mosaicism in peripheral blood is low (<0.5%) from birth until 50 years of age, after which it rises rapidly to 2–3% in the elderly. Many of the mosaic anomalies are characteristic of those found in hematological cancers and identify common deleted regions that pinpoint the locations of genes previously associated with hematological cancers. Although only 3% of subjects with detectable clonal mosaicism had any record of hematological cancer prior to DNA sampling, those without a prior diagnosis have an estimated 10-fold higher risk of a subsequent hematological cancer (95% confidence interval = 6–18).

Background

Mood disorders may affect lung cancer risk. We evaluated this hypothesis in two large studies.

Methodology/Principal Findings

We examined 1,939 lung cancer cases and 2,102 controls from the Environment And Genetics in Lung cancer Etiology (EAGLE) case-control study conducted in Italy (2002–2005), and 82,945 inpatients with a lung cancer diagnosis and 3,586,299 person-years without a lung cancer diagnosis in the U.S. Veterans Affairs Inpatient Cohort (VA study), composed of veterans with a VA hospital admission (1969–1996). In EAGLE, we calculated odds ratios (ORs) and 95% confidence intervals (CI), with extensive adjustment for tobacco smoking and multiple lifestyle factors. In the VA study, we estimated lung cancer relative risks (RRs) and 95% CIs with time-dependent Poisson regression, adjusting for attained age, calendar year, hospital visits, time within the study, and related previous medical diagnoses. In EAGLE, we found decreased lung cancer risk in subjects with a personal history of mood disorders (OR: 0.59, 95% CI: 0.44–0.79, based on 121 lung cancer incident cases and 192 controls) and family history of mood disorders (OR: 0.62, 95% CI: 0.50–0.77, based on 223 lung cancer cases and 345 controls). The VA study analyses yielded similar results (RR: 0.74, 95% CI: 0.71–0.77, based on 2,304 incident lung cancer cases and 177,267 non-cancer person-years) in men with discharge diagnoses for mood disorders. History of mood disorders was associated with nicotine dependence, alcohol and substance use and psychometric scales of depressive and anxiety symptoms in controls for these studies.

Conclusions/Significance

The consistent finding of a relationship between mood disorders and lung cancer risk across two large studies calls for further research into the complex interplay of risk factors associated with these two widespread and debilitating diseases. Although we adjusted for smoking effects in EAGLE, residual confounding of the results by smoking cannot be ruled out.