Studies of smoking and risk of non-Hodgkin lymphoma (NHL) have yielded inconsistent results, possibly due to subtype heterogeneity and/or genetic variation impacting the metabolism of tobacco-derived carcinogens, including substrates of the N-acetyltransferase enzymes NAT1 and NAT2.
We conducted a pooled analysis of 5,026 NHL cases and 4,630 controls from seven case–control studies in the international lymphoma epidemiology consortium to examine associations between smoking, variation in the N-acetyltransferase genes NAT1 and NAT2, and risk of NHL subtypes. Smoking data were harmonized across studies, and genetic variants in NAT1 and NAT2 were used to infer acetylation phenotype of the NAT1 and NAT2 enzymes, respectively. Pooled odds ratios (ORs) and 95 % confidence intervals (95 % CIs) for risk of NHL and subtypes were calculated using joint fixed effects unconditional logistic regression models.
Current smoking was associated with a significant 30 % increased risk of follicular lymphoma (n = 1,176) but not NHL overall or other NHL subtypes. The association was similar among NAT2 slow (OR 1.36; 95 % CI 1.07–1.75) and intermediate/rapid (OR 1.27; 95 % CI 0.95–1.69) acetylators (pinteraction = 0.82) and also did not differ by NAT1*10 allelotype. Neither NAT2 phenotype nor NAT1*10 allelotype was associated with risk of NHL overall or NHL subtypes.
The current findings provide further evidence for a modest association between current smoking and follicular lymphoma risk and suggest that this association may not be influenced by variation in the N-acetyltransferase enzymes.
Non-Hodgkin lymphoma; Gene environment interaction; Cigarette smoking; N-acetyltransferase; Follicular lymphoma
Little is known about survival after a diagnosis of a second or higher order (multiple) primary melanoma. We aimed to determine whether survival after diagnosis was better in patients with multiple primary melanomas (MPM) than with single primary melanomas (SPM), as suggested in a recent study.
Survival analysis with median follow-up of 7.6 years (range 0.4-10.6).
The Genes, Environment and Melanoma (GEM) study enrolled incident cases of melanoma notified to population-based cancer registries in Australia, Canada, Italy and the USA. MPM were ascertained over a longer period than SPM.
2372 patients with SPM and 1206 with MPM.
Main outcome measures
Melanoma-specific fatality hazard ratios (HR) and confidence intervals (CI) associated with clinical and pathologic characteristics of SPM, MPM and both together in Cox regression models.
Thickness was the main determinant of fatality (HR for >4mm=7.68, 95% CI 4.46 to 13.23); other independent predictors were ulceration, mitoses and scalp location. After adjustment for these other predictors, there was little difference in fatality between MPM and SPM (HR for MPM relative to SPM=1.24, 95% CI 0.91 to 1.69; P = .18). Thicker SPM, however, had higher fatality (HR for >4mm=13.56, 95% CI 6.47-28.40) than thicker MPM (HR for >4mm=2.93, 95% CI 1.17-7.30).
While overall fatalities from SPM and MPM were similar, relative fatality for thick SPM was greater than for thick MPM. This finding may offer support for a difference in outcome between patients with SPM and MPM that is worth further exploration.
GEM; MPM; SPM; pathology characteristics; fatality; survival
H2AFX encodes a histone variant involved in signaling sites of DNA damage and recruiting repair factors. Genetic variants in H2AFX may influence risk of non-Hodgkin lymphoma (NHL), a heterogeneous group of lymphoid tumors that are characterized by chromosomal translocations. We previously reported that rs2509049, a common variant in the promoter of H2AFX, was associated with risk for NHL in the British Columbia population. Here we report results for 13 single nucleotide polymorphisms (SNPs) in 100 Kb surrounding H2AFX in an expanded collection of 568 NHL cases and 547 controls. After correction for multiple testing, significant associations were present for mantle cell lymphoma (p=0.007 for rs604714) and all B-cell lymphomas (p=0.046 for rs2509049). Strong linkage disequilibrium in the 5 Kb upstream of H2AFX limited the ability to determine which specific SNP (rs2509049, rs7759, rs8551, rs643788, rs604714, or rs603826), if any, was responsible. There was a significant interaction between sex and rs2509049 in the all B-cell lymphomas group (p=0.002); a sex-stratified analysis revealed that the association was confined to females (p=0.001). Neither the overall nor the female-specific association with rs2509049 was replicated in any of four independent NHL sample sets. Meta-analysis of all five study populations (3,882 B-cell NHL cases and 3,718 controls) supported a weak association with B-cell lymphoma (OR=0.92, 95% CI=0.86-0.99, p=0.034), although this association was not significant after exclusion of the British Columbia data. Further research into the potential sex-specificity of the H2AFX-NHL association may identify a subset of NHL cases that are influenced by genotype at this locus.
The purpose of this study was to quantify the risk of cancers other than melanoma among family members of CDKN2A mutation carriers using data from the Genes, Environment and Melanoma study. Relative risks (RRs) of all non-melanoma cancers among first-degree relatives (FDRs) of melanoma patients with CDKN2A mutations (n = 65) and FDRs of melanoma patients without mutations (n = 3537) were calculated as the ratio of estimated event rates (number of cancers/total person-years) in FDRs of carriers vs noncarriers with exact Clopper–Pearson-type tests and 95% confidence intervals (CIs). All statistical tests were two-sided. There were 56 (13.1%) non-melanoma cancers reported among 429 FDRs of mutation carriers and 2199 (9.4%) non-melanoma cancers in 23 452 FDRs of noncarriers. The FDRs of carriers had an increased risk of any cancer other than melanoma (56 cancers among 429 FDRs of carrier probands vs 2199 cancers among 23 452 FDRs of noncarrier probands; RR = 1.5, 95% CI = 1.2 to 2.0, P = .005), gastrointestinal cancer (20 cancers among 429 FDRs of carrier probands vs 506 cancers among 23 452 FDRs of noncarrier probands; RR = 2.4, 95% CI = 1.4 to 3.7, P = .001), and pancreatic cancer (five cancers among 429 FDRs of carrier probands vs 41 cancers among 23 452 FDRs of noncarrier probands; RR = 7.4, 95% CI = 2.3 to 18.7, P = .002). Wilms tumor was reported in two FDRs of carrier probands and three FDRs of noncarrier probands (RR = 40.4, 95% CI = 3.4 to 352.7, P = .005). The lifetime risk of any cancer other than melanoma among CDKN2A mutation carriers was estimated as 59.0% by age 85 years (95% CI = 39.0% to 75.4%) by the kin-cohort method, under the standard assumptions of Mendelian genetics on the genotype distribution of FDRs conditional on proband genotype.
0.6–12.7% of patients with primary cutaneous melanoma will develop additional melanomas. Pathologic features of tumors in patients with multiple primary cutaneous melanomas have not been well described. In this large international multi-center case-control study, we compared the clinicopathologic features of a subsequent melanoma with the preceding (usually the first) melanoma in patients with multiple primary cutaneous melanomas, and with those of melanomas in patients with single primary cutaneous melanomas.
Multiple primary melanoma (cases) and single primary invasive melanoma (controls) patients from the Genes, Environment and Melanoma (GEM) study were included if their tumors were available for pathologic review and confirmed as melanoma. Clinicopathologic characteristics of invasive subsequent and first melanomas in cases and invasive single melanomas in controls were compared.
473 pairs comprising a subsequent and a first melanoma and 1989 single melanomas were reviewed. Forward stepwise regression modeling in 395 pairs with complete data showed that, compared to first melanomas, subsequent melanomas were: more commonly contiguous with a dysplastic nevus; more prevalent on the head/neck and legs than other sites; and thinner. Compared with single primary melanomas, subsequent melanomas were also more likely to be: associated with a contiguous dysplastic nevus; more prevalent on the head/neck and legs; and thinner. The same differences were observed when subsequent melanomas were compared with single melanomas. First melanomas were more likely than single melanomas to have associated solar elastosis and no observed mitoses.
Thinner subsequent than first melanomas suggest earlier diagnosis, perhaps due to closer clinical scrutiny. The association of subsequent melanomas with dysplastic nevi is consistent with the latter being risk factors or risk markers for melanoma.
Diagnosis; Melanoma; Multiple primary melanoma; Pathology; Risk factors
The vitamin D receptor (VDR) gene has been associated with cancer risk, but only a few polymorphisms have been studied in relation to melanoma risk and the results have been inconsistent. We examined 38 VDR gene SNPs in a large international multi-center population-based case-control study of melanoma.
Buccal DNAs were obtained from 1207 people with incident multiple primary melanoma and 2469 with incident single primary melanoma. SNPs with known or suspected impact on VDR activity, htSNPs with ≥10% MAF in Caucasians, and SNPs reported as significant in other association studies were examined. Logistic regression was used to calculate the relative risks conferred by the individual SNP.
Eight of 38 SNPs in the promoter, coding, and 3’ gene regions were individually significantly associated with multiple primary melanoma after adjusting for covariates. The estimated increase in risk for individuals who were homozygous for the minor allele ranged from 25% to 33% for 6 polymorphisms: rs10875712 (OR 1.28; 95%CI, 1.01–1.62), rs4760674 (OR 1.33; 95% CI, 1.06–1.67), rs7139166 (OR 1.26; 95%CI, 1.02–1.56), rs4516035 (OR 1.25; 95%CI, 1.01–1.55), rs11168287 (OR 1.27; 95%CI, 1.03–1.57), rs1544410 (OR 1.30; 95%CI, 1.04–1.63); for 2 polymorphisms, homozygous carriers had a decreased risk: rs7305032 (OR 0.81; 95%CI 0.65–1.02), rs7965281 (OR, 0.78; 95%CI, 0.62–0.99). We recognize the potential false positive findings due to multiple comparisons; however the 8 significant SNPs in this study outnumbered the 2 significant tests expected to occur by chance. The vitamin D receptor may play a role in melanomagenesis.
VDR; SNP; melanoma; polymorphism; vitamin D
Sunlight exposure increases risk of melanoma. Sunlight also potentiates cutaneous synthesis of vitamin D, which can inhibit melanoma cell growth and promote apoptosis. Vitamin D effects are mediated through the vitamin D receptor (VDR). We hypothesized that genetic variation in VDR affects the relationship of sun exposure to risk of a further melanoma in people who have already had one.
We investigated the interaction between VDR polymorphisms and sun exposure in a population-based multinational study comparing 1138 patients with a multiple (second or subsequent) primary melanoma (cases) to 2151 patients with a first primary melanoma (controls); essentially a case-control study of melanoma in a population of melanoma survivors. Sun exposure was assessed using a questionnaire and interview, and was shown to be associated with multiple primary melanoma. VDR was genotyped at the FokI and BsmI loci and the main effects of variants at these loci and their interactions with sun exposure were analyzed.
Only the BsmI variant was associated with multiple primary melanoma (OR = 1.27, 95% CI 0.99-1.62 for the homozygous variant genotype). Joint effects analyses showed highest ORs in the high exposure, homozygous variant BsmI genotype category for each sun exposure variable. Stratified analyses showed somewhat higher ORs for the homozygous BsmI variant genotype in people with high sun exposure than with low sun exposure. P values for interaction, however, were high.
These results suggest that risk of multiple primary melanoma is increased in people who have the BsmI variant of VDR.
melanoma; FokI; BsmI; sun exposure
The balance between Th1 and Th2 activity is critical in lymphoid cell development and differentiation. Immune dysfunction underlies lymphomagenesis, so an alteration in the regulation of key Th1/Th2 cytokines may lead to the development of non-Hodgkin lymphoma (NHL). To study the impact of polymorphism in Th1/Th2 cytokines on NHL risk, we analyzed 145 tag single nucleotide polymorphisms (SNPs) in 17 Th1/Th2 cytokine and related genes in three population-based case-control studies (1,946 cases and 1,808 controls). Logistic regression was used to compute odds ratios (OR) for NHL and four major NHL subtypes in relation to tag SNP genotypes and haplotypes. A gene-based analysis adjusting for the number of tag SNPs genotyped in each gene showed significant associations with risk of NHL combined and one or more NHL subtypes for Th1 (IL12A and IL12RB1) and Th2 (IL4, IL10RB, and IL18) genes. The strongest association was for IL12A rs485497, which plays a central role in bridging the cellular and humoral pathways of innate resistance and antigen-specific adaptive immune responses (allele risk OR=1.17; P(trend)=0.00099). This SNP was also associated specifically with risk of follicular lymphoma (allele risk OR=1.26; P(trend)=0.0012). These findings suggest that genetic variation in Th1/Th2 cytokine genes may contribute to lymphomagenesis.
Non-Hodgkin lymphoma; single nucleotide polymorphisms; immunogenetics; case-control study
Genetic variation in immune-related genes may play a role in the development of non-Hodgkin lymphoma (NHL). To test the hypothesis that innate immunity polymorphisms may be associated with NHL risk, we genotyped 144 tag single nucleotide polymorphisms (tagSNPs) capturing common genetic variation within 12 innate immunity gene regions in three independent population-based case-control studies (1946 cases and 1808 controls). Gene-based analyses found IL1RN to be associated with NHL risk (minP = 0.03); specifically, IL1RN rs2637988 was associated with an increased risk of NHL (per-allele odds ratio = 1.15, 95% confidence interval = 1.05 – 1.27; ptrend = 0.003), which was consistent across study, subtype, and gender. FCGR2A was also associated with a decreased risk of the follicular lymphoma NHL subtype (minP = 0.03). Our findings suggest that genetic variation in IL1RN and FCGR2A may play a role in lymphomagenesis. Given that conflicting results have been reported regarding the association between IL1RN SNPs and NHL risk, a larger number of innate immunity genes with sufficient genomic coverage should be evaluated systematically across many studies.
non-Hodgkin lymphoma; immune; innate immunity; genetic variation; single nucleotide polymorphisms
We investigated whether MC1R genotype modifies the effect of sun exposure on melanoma risk in 1,018 cases with multiple melanomas (MPM) and 1,875 controls with one melanoma (SPM). There was some suggestion that MC1R genotype modified the effect of beach and water activities on MPM risk: ORs were 1.94 (95% CI 1.40–2.70) for any activities for no R variants and 1.39 (95% CI 1.05–1.84) with R variants (R151C, R160W, D294H, D84E) (p for interaction 0.08). MC1R modification of sun exposure effects appeared most evident for MPM of the head and neck: for early life ambient UV the OR was 4.23 (95% CI 1.76–10.20) with no R and 1.04 (95% CI 0.40–2.68) with R (p for interaction=0.01; p for three-way interaction=0.01). Phenotype modified the effect of sun exposure and MPM in a similar manner. We conclude that MC1R and pigmentary phenotype may modify the effects of sun exposure on melanoma risk on more continuously sun-exposed skin. Possible explanations include that risk may saturate with higher sun sensitivity for melanomas on continuously sun-exposed sites but continue to increase as sun exposure increases with lower sun sensitivity, or that sun sensitive people adapt their behaviour by increasing sun protection when exposed.
melanoma; MC1R polymorphism; sun exposure; pigmentary phenotype
Solar elastosis adjacent to melanomas in histologic sections is regarded as an indicator of sun exposure although the associations of ultraviolet (UV) exposure and phenotype with solar elastosis are yet to be fully explored.
The study included 2,589 incident primary melanoma patients with assessment of histologic solar elastosis in the population-based Genes, Environment, and Melanoma study. Ambient erythemal UV (UVE) at places of residence and sun exposure hours, including body site-specific exposure, were collected. We examined the association of cumulative site-specific and non site-specific sun exposure hours and ambient UVE with solar elastosis in multivariable models adjusted for age, sex, center, pigmentary characteristics, nevi and, where relevant, body site.
Solar elastosis was associated most strongly with site-specific UVE (OR for top exposure quartile, 5.20; 95% CI, 3.40-7.96; P for trend <0.001) and also with site-specific sun exposure (OR for top quartile, 5.12; 95% CI, 3.35-7.83; P for trend <0.001). Older age (OR at >70 years, 7.69; 95% CI, 5.14-11.52); P trend < 0.001) and having more than 10 back nevi (OR, 0.77; 95% CI, 0.61-0.97; P = 0.03) were independently associated with solar elastosis.
Solar elastosis had a strong association with higher site-specific UVE dose, older age and fewer nevi.
Solar elastosis could be a useful biomarker of lifetime site-specific UV. Future research is needed to explore whether age represents more than simple accumulation of sun exposure and the reason that people with more nevi may be less prone to solar elastosis.
solar elastosis; UV; sun exposure; pigmentation; nevi
Non-Hodgkin lymphoma (NHL) represents a diverse group of hematological
malignancies, of which follicular lymphoma (FL) is a prevalent subtype. A
previous genome-wide association study has established a marker, rs10484561 in
the human leukocyte antigen (HLA) class II region on 6p21.32 associated with
increased FL risk. Here, in a three-stage genome-wide association study,
starting with a genome-wide scan of 379 FL cases and 791 controls followed by
validation in 1,049 cases and 5,790 controls, we identified a second independent
FL–associated locus on 6p21.32, rs2647012
(ORcombined = 0.64,
Pcombined = 2×10−21)
located 962 bp away from rs10484561 (r2<0.1 in controls). After
mutual adjustment, the associations at the two SNPs remained genome-wide
significant (rs2647012:ORadjusted = 0.70,
Padjusted = 4×10−12;
rs10484561:ORadjusted = 1.64,
Padjusted = 5×10−15).
Haplotype and coalescence analyses indicated that rs2647012 arose on an
evolutionarily distinct haplotype from that of rs10484561 and tags a novel
allele with an opposite (protective) effect on FL risk. Moreover, in a follow-up
analysis of the top 6 FL–associated SNPs in 4,449 cases of other NHL
subtypes, rs10484561 was associated with risk of diffuse large B-cell lymphoma
(ORcombined = 1.36,
Pcombined = 1.4×10−7).
Our results reveal the presence of allelic heterogeneity within the HLA class II
region influencing FL susceptibility and indicate a possible shared genetic
etiology with diffuse large B-cell lymphoma. These findings suggest that the HLA
class II region plays a complex yet important role in NHL.
Earlier studies have established a marker rs10484561, in the HLA class II region
on 6p21.32, associated with increased follicular lymphoma (FL) risk. Here, in a
three-stage genome-wide association study of 1,428 FL cases and 6,581 controls,
we identified a second independent FL–associated marker on 6p21.32,
rs2647012, located 962 bp away from rs10484561. The associations at two SNPs
remained genome-wide significant after mutual adjustment. Haplotype and
coalescence analyses indicated that rs2647012 arose on an evolutionarily
distinct lineage from that of rs10484561 and tags a novel allele with an
opposite, protective effect on FL risk. Moreover, in an analysis of the top 6
FL–associated SNPs in 4,449 cases of other NHL subtypes, rs10484561 was
associated with risk of diffuse large B-cell lymphoma. Our results reveal the
presence of allelic heterogeneity at 6p21.32 in FL risk and suggest a shared
genetic etiology with the common diffuse large B-cell lymphoma subtype.
To identify susceptibility loci for non-Hodgkin lymphoma (NHL) subtypes, we conducted a three-stage genome-wide association study. We identified two variants associated with follicular lymphoma (FL) in 1,465 FL cases/6,958 controls at 6p21.32 (rs10484561, rs7755224, r2=1.0; combined p-values=1.12×10-29, 2.00×10-19), providing further support that MHC genetic variation influences FL susceptibility. Confirmatory evidence of a previously reported association was also found between chronic lymphocytic leukemia/small lymphocytic lymphoma and rs735665 (combined p-value=4.24×10-9).
In an International Lymphoma Epidemiology Consortium pooled analysis, polymorphisms in 2 immune-system-related genes, tumor necrosis factor (TNF) and interleukin-10 (IL10), were associated with non-Hodgkin lymphoma (NHL) risk. Here, 8,847 participants were added to previous data (patients diagnosed from 1989 to 2005 in 14 case-control studies; 7,999 cases, 8,452 controls) for testing of polymorphisms in the TNF –308G>A (rs1800629), lymphotoxin-α (LTA) 252A>G (rs909253), IL10 –3575T>A (rs1800890, rs1800896), and nucleotide-binding oligomerization domain containing 2 (NOD2) 3020insC (rs2066847) genes. Odds ratios were estimated for non-Hispanic whites and several ethnic subgroups using 2-sided tests. Consistent with previous findings, odds ratios were increased for “new” participant TNF –308A carriers (NHL: per-allele odds ratio (ORallelic) = 1.10, Ptrend = 0.001; diffuse large B-cell lymphoma (DLBCL): ORallelic = 1.23, Ptrend = 0.004). In the combined population, odds ratios were increased for TNF –308A carriers (NHL: ORallelic = 1.13, Ptrend = 0.0001; DLBCL: ORallelic = 1.25, Ptrend = 3.7 × 10−6; marginal zone lymphoma: ORallelic = 1.35, Ptrend = 0.004) and LTA 252G carriers (DLBCL: ORallelic = 1.12, Ptrend = 0.006; mycosis fungoides: ORallelic = 1.44, Ptrend = 0.015). The LTA 252A>G/TNF –308G>A haplotype containing the LTA/TNF variant alleles was strongly associated with DLBCL (P = 2.9 × 10−8). Results suggested associations between IL10 –3575T>A and DLBCL (Ptrend = 0.02) and IL10 –1082A>G and mantle cell lymphoma (Ptrend = 0.04). These findings strengthen previous results for DLBCL and the LTA 252A>G/TNF –308A locus and provide robust evidence that these TNF/LTA gene variants, or others in linkage disequilibrium, are involved in NHL etiology.
lymphoma; lymphoma, non-Hodgkin; lymphotoxin-alpha; meta-analysis; polymorphism, genetic; polymorphism, single nucleotide; tumor necrosis factor-alpha
Elevated incidence of lymphoma has been observed among carriers of rare high-penetrance mutations in DNA repair genes (e.g., Nijmegen breakage syndrome, Ataxia-telangectasia syndrome, etc.). Common gene variants in DNA repair genes may also influence lymphomagenesis.
Study subjects were pooled from three population-based case-control studies of non-Hodgkin lymphoma (NHL) in the US and Australia. A total of 1,946 cases and 1,808 controls were analyzed. A total of 319 tag single nucleotide polymorphisms (SNPs) in 27 DNA repair gene regions were genotyped. Unconditional logistic regression models were used to estimate the relative risk of NHL and NHL subtypes in relation to SNPs. Tail-strength statistics were used to test for the association between DNA repair pathways and NHL or NHL subtypes. The statistical significance of the smallest P-trend within each gene region was estimated by permutation-based resampling methods.
Overall, DNA repair genetic polymorphisms were associated with NHL (P = 0.005). Tests for the double strand break repair (P = 0.02) and nucleotide excision repair (P = 0.04) pathways were also significant. Four gene regions were significantly associated with NHL or NHL subtypes at the 0.05 level: RAD50, BLM, RAD51/FAM82C, and ERCC3/MAP3K2. Specifically, BLM rs441399 (P trend = 0.004) and FAM82C rs2304583 (P trend = 0.001) were associated with follicular lymphoma, and XRCC4 rs13178127 was associated with NHL overall (P trend = 0.006) significantly. In addition, the ERCC3 rs4150506 was associated with reduced risk for marginal zone lymphoma (P trend = 0.002).
These results support the hypothesis that common genetic polymorphisms in human DNA repair genes may modify the risk of NHL.
non-Hodgkin lymphoma; DNA repair; single nucleotide polymorphism; pooled analysis
Chromosomal translocations are the hallmark genetic aberration in non-Hodgkin lymphoma (NHL), with specific translocations often selectively associated with specific NHL subtypes. Because many NHL-associated translocations involve cell cycle, apoptosis, and lymphocyte development regulatory genes, we evaluated NHL risk associated with common genetic variation in 20 candidate genes in these pathways. Genotyping of 203 tag single nucleotide polymorphisms (SNPs) was conducted in 1946 NHL cases and 1808 controls pooled from three independent population-based case-control studies. We used logistic regression to compute odds ratios (OR) and 95% confidence intervals (CI) for NHL and four major NHL subtypes in relation to tag SNP genotypes and haplotypes. We observed the most striking associations for tag SNPs in the pro-apoptotic gene BCL2L11 (BIM) and BCL7A, which is involved in a rare NHL-associated translocation. Variants in BCL2L11 were strongly related to follicular lymphoma only, particularly rs3789068 (ORAG=1.41, 95%CI 1.10–1.81; ORGG=1.65, 95%CI 1.25–2.19; p-trend=0.0004). Variants in BCL7A were strongly related to diffuse large B-cell lymphoma only, particularly rs1880030 (ORAG=1.34, 95%CI 1.08–1.68; ORAA=1.60, 95%CI 1.22–2.08; p-trend=0.0004). The associations for both variants were similar in all three studies and supported by haplotype analyses. We also observed notable associations for variants in BCL6, CCND1, and MYC. Our results support the role of common genetic variation in cell cycle, apoptosis, and lymphocyte development regulatory genes in lymphomagenesis, and suggest that effects may vary by NHL subtype. Replication of our findings and further study to identify functional SNPs are warranted.
lymphoma; non-Hodgkin; polymorphism; single nucleotide; apoptosis; cell cycle
Toll-like receptors (TLRs) may influence the development of non-Hodgkin lymphoma (NHL) given their important roles in recognizing microbial pathogens and stimulating multiple immune pathways. We conducted an investigation of TLR gene variants in a pooled analysis including three population-based case–control studies of NHL (1946 cases and 1808 controls). Thirty-six tag single-nucleotide polymorphisms (SNPs) in TLR2, TLR4 and the TLR10–TLR1–TLR6 gene cluster were genotyped. Two TLR10–TLR1–TLR6 variants in moderate linkage disequilibrium were significantly associated with NHL: rs10008492 [odds ratio for CT genotype (ORCT) 1.12, 95% confidence interval (CI) 0.97–1.30; ORTT 1.40, 95% CI 1.15–1.71; Ptrend = 0.001] and rs4833103 (ORAC 0.75, 95% CI 0.64–0.88; ORAA 0.74, 95% CI 0.62–0.90; Ptrend = 0.002; Pdominant = 0.0002). Associations with these SNPs were consistent across all the three studies and did not appreciably differ by histologic subtype. We found little evidence of association between TLR2 variation and all NHL, although the rare variant rs3804100 was significantly associated with marginal zone lymphoma (MZL), both overall (ORCT/CC 1.89, 95% CI 1.27–2.81; Pdominant = 0.002) and in two of the three studies. No associations with TLR4 variants were observed. This pooled analysis provides strong evidence that variation in the TLR10–TLR1–TLR6 region is associated with NHL risk and suggests that TLR2 variants may influence susceptibility to MZL.
Few studies have evaluated the reliability of lifetime sun exposure estimated from inquiring about the number of hours people spent outdoors in a given period on a typical weekday or weekend day (the time-based approach). Some investigations have suggested that women have a particularly difficult task in estimating time outdoors in adulthood due to their family and occupational roles. We hypothesized that people might gain additional memory cues and estimate lifetime hours spent outdoors more reliably if asked about time spent outdoors according to specific activities (an activity-based approach). Using self-administered, mailed questionnaires, test-retest responses to time-based and to activity-based approaches were evaluated in 124 volunteer U.S. radiologic technologist participants: 64 females and 60 males 48 to 80 years of age. Intraclass correlation coefficients (ICCs) were used to evaluate the test-retest reliability of average numbers of hours spent outdoors in summer estimated for each approach. We tested the differences between the two ICCs, corresponding to each approach, using a t-test with the variance of the difference estimated by the Jackknife method. During childhood and adolescence, the two approaches gave similar ICCs for average numbers of hours spent outdoors in summer. By contrast, compared with the time-based approach, the activity-based approach showed significantly higher ICCs during adult ages (0.69 vs. 0.43, P=0.003) and over the lifetime (0.69 vs. 0.52, P=0.05); the higher ICCs for the activity-based questionnaire were primarily derived from the results for females. Research is needed to further improve the activity-based questionnaire approach for long-term sun exposure assessment.
Ultraviolet (UV) radiation; epidemiologic methods; gender; sun exposure; occupational cohort
A promoter polymorphism in the pro-inflammatory cytokine tumor necrosis factor (TNF) (TNF G-308A) is associated with increased non-Hodgkin lymphoma (NHL) risk. The protein product, TNF-α, activates the nuclear factor kappa beta (NF-κB) transcription factor, and is critical for inflammatory and apoptotic responses in cancer progression. We hypothesized that the TNF and NF-κB pathways are important for NHL and that gene variations across the pathways may alter NHL risk.
We genotyped 500 tag single nucleotide polymorphisms (SNPs) from 48 candidate gene regions (defined as 20 kb 5′, 10 kb 3′) in the TNF and TNF receptor superfamilies and the NF-κB and related transcription factors, in 1946 NHL cases and 1808 controls pooled from three independent population-based case-control studies. We obtaineded a gene region-level summary of association by computing the minimum p-value (“minP test”). We used logistic regression to compute odds ratios and 95% confidence intervals for NHL and four major NHL subtypes in relation to SNP genotypes and haplotypes. For NHL, the tail strength statistic supported an overall relationship between the TNF/NF-κB pathway and NHL (p = 0.02). We confirmed the association between TNF/LTA on chromosome 6p21.3 with NHL and found the LTA rs2844484 SNP most significantly and specifically associated with the major subtype, diffuse large B-cell lymphoma (DLBCL) (p-trend = 0.001). We also implicated for the first time, variants in NFKBIL1 on chromosome 6p21.3, associated with NHL. Other gene regions identified as statistically significantly associated with NHL included FAS, IRF4, TNFSF13B, TANK, TNFSF7 and TNFRSF13C. Accordingly, the single most significant SNPs associated with NHL were FAS rs4934436 (p-trend = 0.0024), IRF4 rs12211228 (p-trend = 0.0026), TNFSF13B rs2582869 (p-trend = 0.0055), TANK rs1921310 (p-trend = 0.0025), TNFSF7 rs16994592 (p-trend = 0.0024), and TNFRSF13C rs6002551 (p-trend = 0.0074). All associations were consistent in each study with no apparent specificity for NHL subtype.
Our results provide consistent evidence that variation in the TNF superfamily of genes and specifically within chromosome 6p21.3 impacts lymphomagenesis. Further characterization of these susceptibility loci and identification of functional variants are warranted.