Cerhan, James R.

Abstract Background. Non-Hodgkin lymphoma (NHL) case-control studies consistently demonstrate the G-308A promoter polymorphism in the tumor necrosis factor gene on chromosome 6p21.3 to be associated with increased risk of the NHL subtype, diffuse large B-cell lymphoma (DLBCL). Initial results from a genome-wide association study have implicated a polymorphism located on 6p21.33 with increased risk of the follicular lymphoma subtype. In the present analysis, we evaluated 488 candidate gene regions (defined as 20kb 5’, 10kb 3’) and their relation to risk for NHL and the DLBCL and follicular lymphoma subtypes with a particular focus on genes within the 6p21 chromosomal region. Methods. We genotyped 6679 tag single nucleotide polymorphisms (SNPs) in 947 cases and 826 population-based controls from a multicenter U.S.-based case-control study. Genotyping was conducted on a custom-designed Illumina Infinium assay at the NCI Core Genotyping Facility. We obtained a gene region-level summary of association by computing the minimum p-value (“minP test”). We used logistic regression to evaluate the association between single nucleotide polymorphism (SNP) genotypes and haplotypes with NHL (adjusted for sex, race and age). For NHL subtypes, we conducted polytomous multivariate unconditional logistic regression. We evaluated tests for trend under the co-dominant model used a three-level ordinal variable for each SNP. Results. We identified 34 gene regions significantly associated with all NHL (p <0.05). The three most significant gene regions were all found on chromosome 6p21.3 (RING1/RXRB; AIF1/BAT2; BAT4, p=0.001). Within those gene regions, the most significant SNPs (p<0.0002) were rs2855429 and rs213213 (RING1/RXRB), rs2857597 and rs3130071 (AIF1/BAT2), and rs3115667 (BAT4). All five SNPs were statistically significantly associated with both DLBCL and follicular lymphoma. Additional gene regions on 6p21.3 associated with NHL include MSH5 (p=0.009), FAM46A (p=0.01) and TNXB/CREBL1 (p=0.04). Stratification by age and gender did not alter our results; consistent results were observed in analyses restricted to non-Hispanic Caucasians. Haplotype analyses yielded the same regions and SNPs of significance. Detailed analysis of the 6p21.3 region will be presented. Conclusions. Our results further implicate gene variants within the 6p21.3 chromosomal region in NHL etiology. Full characterization of the 6p21.3 region and identification of functional variants within this region are warranted for understanding lymphomagenesis. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 935.

Abstract Subclinical variation in immune response may be a risk factor for non-Hodgkin lymphoma (NHL). Endotoxin is a substance located in the cell wall of gram-negative bacteria that elicits a strong innate and inflammatory immune response. It is present in large amounts in animal and human fecal material, other organic material, and cigarette smoke. We hypothesized that higher endotoxin exposure might be a risk factor for NHL because of its effect on B-cell activation. Using a population based, multi-center (Detroit, Iowa, Los Angeles and Seattle) case-control study, we evaluated the association between endotoxin levels in carpet dust and NHL risk. During an in-person interview, we collected used vacuum cleaner bags from participants who had used their vacuum within the past year and had owned at least half of their carpets or rugs for 5 years or more. Dust samples were analyzed using the kinetic chromogenic Limulus amebocyte lysate assay in the Pulmonary Toxicology Facility, University of Iowa. Endotoxin measurements from 629 cases and 467 controls were log-transformed and evaluated as both continuous and categorical variables. In order to examine a possible threshold effect, endotoxin levels among controls were categorized into tertiles, with the highest tertile further split into two equal groups based on a preliminary model search. Multivariable logistic regression was used to estimate the effect of endotoxin on NHL risk adjusted for sex, age, race, education, study center, and last change of vacuum bag. The highest category of household endotoxin level in dust was associated with a 35% significantly decreased risk of NHL relative to the lowest category (95% confidence interval [CI] = 0.44, 0.96). The effect was stronger for the diffuse large B-cell lymphoma (DLBCL) subtype (Odds Ratio [OR]= 0.49; 95% CI= 0.26,0.91). In conclusion, contrary to our initial hypothesis, our results suggest an inverse association between high levels of household endotoxin and NHL risk. Further studies are needed to validate this finding, ideally with endotoxin measurements prior to diagnosis. Possible mechanisms of action will be discussed. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 5736.

Abstract Background: There is growing evidence linking genetic variations to non–Hodgkin lymphoma (NHL) etiology. To complement ongoing agnostic approaches for identifying susceptibility genes, we evaluated 488 candidate gene regions and their relation to risk for NHL and NHL subtypes. Methods: We genotyped 6,679 tag single nucleotide polymorphisms (SNPs) in 947 cases and 826 population-based controls from a multicenter U.S. case–control study. Gene-level summary of associations were obtained by computing the minimum P value (“minP test”) on the basis of 10,000 permutations. We used logistic regression to evaluate the association between genotypes and haplotypes with NHL. For NHL subtypes, we conducted polytomous multivariate unconditional logistic regression (adjusted for sex, race, age). We calculated P-trends under the codominant model for each SNP. Results: Fourteen gene regions were associated with NHL (P < 0.01). The most significant SNP associated with NHL maps to the SYK gene (rs2991216, P-trend = 0.00005). The three most significant gene regions were on chromosome 6p21.3 (RING1/RXRB; AIF1; BAT4). Accordingly, SNPs in RING1/RXRB (rs2855429), AIF1 (rs2857597), and BAT4 (rs3115667) were associated with NHL (P-trends ≤ 0.0002) and both diffuse large B-cell and follicular lymphomas (P-trends < 0.05). Conclusions: Our results suggest potential importance for SYK on chromosome 9 with NHL etiology. Our results further implicate 6p21.3 gene variants, supporting the need for full characterization of this chromosomal region in relation to lymphomagenesis. Impact: Gene variants on chromosome 9 may represent a new region of interesting for NHL etiology. The independence of the reported variants in 6p21.3 from implicated variants (TNF/HLA) supports the need to confirm causal variants in this region Cancer Epidemiol Biomarkers Prev; 20(1); 42–9. ©2011 AACR.

Abstract 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.

Abstract Background: The t(14;18)(q32;q21) translocation is the most commonly observed chromosomal translocation in non–Hodgkin's lymphoma (NHL), resulting in constitutive Bcl-2 expression and apoptosis inhibition. In addition, germline variation in both BCL2L11 (BIM) and CASP9, known regulators of apoptosis, has recently been linked to NHL risk. We conducted a comprehensive evaluation of 36 apoptosis pathway genes with risk of NHL. Methods: We genotyped 226 single-nucleotide polymorphisms (SNP) from 36 candidate genes in a clinic-based study of 441 newly diagnosed NHL cases and 475 frequency-matched controls. We used principal components analysis to assess gene-level associations, and logistic regression to assess SNP-level associations. MACH was used for imputation of SNPs in BCL2L11 and CASP9. Results: In gene-level analyses, BCL2L11 (P = 0.0019), BCLAF1 (P = 0.0097), BAG5 (P = 0.026), and CASP9 (P = 0.0022) were associated with NHL risk after accounting for multiple testing (tail strength, 0.38; 95% confidence interval, 0.05-0.70). Two of the five BCL2L11 tagSNPs (rs6746608 and rs12613243), both genotyped BCLAF1 tagSNPs (rs797558 and rs703193), the single genotyped BAG5 tagSNP (rs7693), and three of the seven genotyped CASP9 tagSNPs (rs6685648, rs2020902, and rs2042370) were significant at P < 0.05. We successfully imputed BCL2L11 and CASP9 SNPs previously linked to NHL, and replicated all four BCL2L11 and two of three CASP9 SNPs. Conclusion: We replicated the association of BCL2L11 and CASP9 with NHL risk at the gene and SNP level, and identified novel associations with BCLAF1 and BAG5. Impact: Closer evaluation of germline variation of genes in the apoptosis pathway with risk of NHL and its subtypes is warranted. Cancer Epidemiol Biomarkers Prev; 19(11); 2847–58. ©2010 AACR.

Abstract Vitamin D insufficiency is common globally and low levels are linked to higher cancer incidence. Although vitamin D insufficiency is related to inferior prognosis in some cancers, no data exist for chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL). We evaluated the relationship of 25(OH)D serum levels with time-to-treatment (TTT) and overall survival (OS) in newly diagnosed CLL patients participating in a prospective cohort study (discovery cohort) and a separate cohort of previously untreated patients participating in an observational study (confirmation cohort). Of 390 CLL patients in the discovery cohort, 119 (30.5%) were 25(OH)D insufficient. After a median follow-up of 3 years, TTT (hazard ratio[HR] = 1.66; P = .005) and OS (HR = 2.39; P = .01) were shorter for 25(OH)D-insufficient patients. In the validation cohort, 61 of 153 patients (39.9%) were 25(OH)D insufficient. After a median follow-up of 9.9 years, TTT (HR = 1.59; P = .05) and OS (HR 1.63; P = .06) were again shorter for 25(OH)D-insufficient patients. On pooled multivariable analysis of patients in both cohorts adjusting for age, sex, Rai stage, CD38 status, ZAP-70 status, immunoglobulin heavy chain variable (IGHV) gene mutation status, CD49d status, and cytogenetic abnormalities assessed by interphase fluorescent in situ hybridization testing, 25(OH)D insufficiency remained an independent predictor of TTT (HR = 1.47; P = .008), although the association with OS was not significant (HR = 1.47; P = .07). Vitamin D insufficiency is associated with inferior TTT and OS in CLL patients. Whether normalizing vitamin D levels in deficient CLL patients would improve outcome merits clinical testing.

Abstract Background Previous epidemiologic findings suggest an association between exposure to trichloroethylene (TCE), a chlorinated solvent primarily used for vapor degreasing of metal parts, and non-Hodgkin lymphoma (NHL). Objectives We investigated the association between occupational TCE exposure and NHL within a population-based case–control study using detailed exposure assessment methods. Methods Cases (n = 1,189; 76% participation rate) and controls (n = 982; 52% participation rate) provided information on their occupational histories and, for selected occupations, on possible workplace exposure to TCE using job-specific interview modules. An industrial hygienist assessed potential TCE exposure based on this information and a review of the TCE industrial hygiene literature. We computed odds ratios (ORs) and 95% confidence intervals (CIs) relating NHL and different metrics of estimated TCE exposure, categorized using tertiles among exposed controls, with unexposed subjects as the reference group. Results We observed associations with NHL for the highest tertiles of estimated average weekly exposure (23 exposed cases; OR = 2.5; 95% CI, 1.1–6.1) and cumulative exposure (24 exposed cases; OR = 2.3; 95% CI, 1.0–5.0) to TCE. Tests for trend with these metrics surpassed or approached statistical significance (p-value for trend = 0.02 and 0.08, respectively); however, we did not observe dose–response relationships across the exposure levels. Overall, neither duration nor intensity of exposure was associated with NHL, although we observed an association with the lowest tertile of exposure duration (OR = 2.1; 95% CI, 1.0–4.7). Conclusions Our findings offer additional support for an association between high levels of exposure to TCE and increased risk of NHL. However, we cannot rule out the possibility of confounding from other chlorinated solvents used for vapor degreasing and note that our exposure assessment methods have not been validated.

The cytokine B cell activating factor (BAFF) and its receptor, BAFF receptor (BAFF-R), modulate signaling cascades critical for B cell development and survival. We identified a novel mutation in TNFRSF13C, the gene encoding human BAFF-R, that is present in both tumor and germline tissue from a subset of patients with non-Hodgkin lymphoma. This mutation encodes a His159Tyr substitution in the cytoplasmic tail of BAFF-R adjacent to the TRAF3 binding motif. Signaling through this mutant BAFF-R results in increased NF-κB1 and NF-κB2 activity and increased immunoglobulin production compared with the wild-type (WT) BAFF-R. This correlates with increased TRAF2, TRAF3, and TRAF6 recruitment to His159Tyr BAFF-R. In addition, we document a requirement for TRAF6 in WT BAFF-R signaling. Together, these data identify a novel lymphoma-associated mutation in human BAFF-R that results in NF-κB activation and reveals TRAF6 as a necessary component of normal BAFF-R signaling.