An intestinal organoid-based platform that recreates susceptibility to T-cell-mediated tissue injury.

A goal in precision medicine is to use patient-derived material to predict disease course and intervention outcomes. Here, we use mechanistic observations in a preclinical animal model to design an ex vivo platform that recreates genetic susceptibility to T-cell-mediated damage. Intestinal graft-versus-host disease (GVHD) is a life-threatening complication of allogeneic hematopoietic cell transplantation. We found that intestinal GVHD in mice deficient in Atg16L1, an autophagy gene that is polymorphic in humans, is reversed by inhibiting necroptosis. We further show that cocultured allogeneic T cells kill Atg16L1-mutant intestinal organoids from mice, which was associated with an aberrant epithelial interferon signature. Using this information, we demonstrate that pharmacologically inhibiting necroptosis or interferon signaling protects human organoids derived from individuals harboring a common ATG16L1 variant from allogeneic T-cell attack. Our study provides a roadmap for applying findings in animal models to individualized therapy that targets affected tissues.

Caspase-8 Collaborates with Caspase-11 to Drive Tissue Damage and Execution of Endotoxic Shock.

The execution of shock following high dose E. coli lipopolysaccharide (LPS) or bacterial sepsis in mice required pro-apoptotic caspase-8 in addition to pro-pyroptotic caspase-11 and gasdermin D. Hematopoietic cells produced MyD88- and TRIF-dependent inflammatory cytokines sufficient to initiate shock without any contribution from caspase-8 or caspase-11. Both proteases had to be present to support tumor necrosis factor- and interferon-ß-dependent tissue injury first observed in the small intestine and later in spleen and thymus. Caspase-11 enhanced the activation of caspase-8 and extrinsic cell death machinery within the lower small intestine. Neither caspase-8 nor caspase-11 was individually sufficient for shock. Both caspases collaborated to amplify inflammatory signals associated with tissue damage. Therefore, combined pyroptotic and apoptotic signaling mediated endotoxemia independently of RIPK1 kinase activity and RIPK3 function. These observations bring to light the relevance of tissue compartmentalization to disease processes in vivo where cytokines act in parallel to execute diverse cell death pathways.

Discovery of a First-in-Class Receptor Interacting Protein 1 (RIP1) Kinase Specific Clinical Candidate (GSK2982772) for the Treatment of Inflammatory Diseases.

RIP1 regulates necroptosis and inflammation and may play an important role in contributing to a variety of human pathologies, including immune-mediated inflammatory diseases. Small-molecule inhibitors of RIP1 kinase that are suitable for advancement into the clinic have yet to be described. Herein, we report our lead optimization of a benzoxazepinone hit from a DNA-encoded library and the discovery and profile of clinical candidate GSK2982772 (compound 5), currently in phase 2a clinical studies for psoriasis, rheumatoid arthritis, and ulcerative colitis. Compound 5 potently binds to RIP1 with exquisite kinase specificity and has excellent activity in blocking many TNF-dependent cellular responses. Highlighting its potential as a novel anti-inflammatory agent, the inhibitor was also able to reduce spontaneous production of cytokines from human ulcerative colitis explants. The highly favorable physicochemical and ADMET properties of 5, combined with high potency, led to a predicted low oral dose in humans.

DNA-Encoded Library Screening Identifies Benzo[b][1,4]oxazepin-4-ones as Highly Potent and Monoselective Receptor Interacting Protein 1 Kinase Inhibitors.

The recent discovery of the role of receptor interacting protein 1 (RIP1) kinase in tumor necrosis factor (TNF)-mediated inflammation has led to its emergence as a highly promising target for the treatment of multiple inflammatory diseases. We screened RIP1 against GSK's DNA-encoded small-molecule libraries and identified a novel highly potent benzoxazepinone inhibitor series. We demonstrate that this template possesses complete monokinase selectivity for RIP1 plus unique species selectivity for primate versus nonprimate RIP1. We elucidate the conformation of RIP1 bound to this benzoxazepinone inhibitor driving its high kinase selectivity and design specific mutations in murine RIP1 to restore potency to levels similar to primate RIP1. This series differentiates itself from known RIP1 inhibitors in combining high potency and kinase selectivity with good pharmacokinetic profiles in rodents. The favorable developability profile of this benzoxazepinone template, as exemplified by compound 14 (GSK'481), makes it an excellent starting point for further optimization into a RIP1 clinical candidate.

High throughput screening identifies ATP-competitive inhibitors of the NLRP1 inflammasome.

Nod-like receptors (NLRs) are cytoplasmic pattern recognition receptors that are promising targets for the development of anti-inflammatory therapeutics. Drug discovery efforts targeting NLRs have been hampered by their inherent tendency to form aggregates making protein generation and the development of screening assays very challenging. Herein we report the results of an HTS screen of NLR family member NLRP1 (NLR family, pyrin domain-containing 1) which was achieved through the large scale generation of recombinant GST-His-Thrombin-NLRP1 protein. The screen led to the identification of a diverse set of ATP competitive inhibitors with micromolar potencies. Activity of these hits was confirmed in a FP binding assay, and two homology models were employed to predict the possible binding mode of the leading series and facilitate further lead-optimization. These results highlight a promising strategy for the identification of inhibitors of NLR family members which are rapidly emerging as key drivers of inflammation in human disease.

Genetic polymorphisms of estrogen receptors alpha and beta and the risk of developing prostate cancer.

Estrogen may be involved in the development of prostate cancer. The association between genetic polymorphisms of estrogen receptors alpha (ESR1) and beta (ESR2) and prostate cancer risk was examined in a nested case-control study in Washington County, Maryland. Incident prostate cancer cases (n = 269) were matched to one or two controls (n = 440) by age, sex, race, and date of blood donation. Associations between estrogen receptor genotypes or dietary intake and the development of prostate cancer were examined in conditional logistic regression models. Results from this study showed that six single base-pair polymorphisms (SNPs) of ESR1 (rs1801132, rs2077647, rs746432, rs2273206, rs851982, rs2228480) and four SNPs of ESR2 (rs4986938, rs928554, rs8018687, rs number not available for ESR2 5696 bp 3' of STP A>G) were not significantly associated with prostate cancer risk, either by allelic or genotypic frequencies. However, an interactive association with BMI was observed in the relationship between prostate cancer risk and genotypes of ESR2 38 bp 3' of STP G>A (rs4986938) (p = 0.031). An interaction between intake level of phytoestrogen and genotypes of ESR1 Ex1-192G>C (rs746432) and between intake level of phytoestrogen and genotypes of ESR1 Ex8+229G>A (rs2228480) and risk of prostate cancer was observed (p = 0.0009 and p = 0.044, respectively). In conclusion, selected genetic polymorphisms of ESR1 and ESR2, overall, were not associated with prostate cancer risk. However, a variation in risk by BMI and phytoestrogen intake was implicated.

Leucocyte cathepsin K affects atherosclerotic lesion composition and bone mineral density in low-density lipoprotein receptor deficient mice.

AIMS: Cathepsin K (CatK), an established drug target for osteoporosis, has been reported to be upregulated in atherosclerotic lesions. Due to its proteolytic activity, CatK may influence the atherosclerotic lesion composition and stability. In this study, we investigated the potential role of leucocyte CatK in atherosclerotic plaque remodelling. METHODS AND RESULTS: To assess the biological role of leucocyte CatK, we used the technique of bone marrow transplantation to selectively disrupt CatK in the haematopoietic system. Total bone marrow progenitor cells from CatK(+/+), CatK(+/-), and CatK(-/-) mice were transplanted into X-ray irradiated low-density lipoprotein receptor knockout (LDLr(-/-)) mice. The selective silencing of leucocyte CatK resulted in phenotypic changes in bone formation with an increased total bone mineral density in the CatK(-/-) chimeras and an effect of gene dosage. The absence of leucocyte CatK resulted in dramatically decreased collagen and increased macrophage content of the atherosclerotic lesions while lesion size was not affected. The atherosclerotic lesions also demonstrated less elastic lamina fragmentation and a significant increase in the apoptotic and necrotic area in plaques of mice transplanted with CatK(-/-) bone marrow. CONCLUSION: Leucocyte CatK is an important determinant of atherosclerotic plaque composition, vulnerability, and bone remodelling, rendering CatK an attractive target for pharmaceutical modulation in atherosclerosis and osteoporosis.

The risk of developing lung cancer associated with antioxidants in the blood: ascorbic acids, carotenoids, alpha-tocopherol, selenium, and total peroxyl radical absorbing capacity.

Lung cancer cases diagnosed during the period 1975 through 1993 and matched controls were identified in the rosters of Washington County, Maryland residents who had donated blood for a serum bank in 1974 or 1989. Plasma from participants in the 1989 project was assayed for ascorbic acid; serum or plasma was assayed for participants in either project for alpha- and beta-carotene, cryptoxanthin, lutein/zeaxanthin, lycopene, alpha-tocopherol, selenium, and peroxyl radical absorption capacity. Among the total group of 258 cases and 515 controls, serum/plasma concentrations were significantly lower among cases than controls for cryptoxanthin, beta-carotene, and lutein/zeaxanthin with case-control differences of -25.5, -17.1, and -10.1%, respectively. Modest nonsignificant case-control differences in a protective direction were noted for alpha-carotene and ascorbic acid. There were only trivial differences for lycopene, alpha-tocopherol, selenium, and peroxyl radical absorption capacity. Findings are reported for males and females and for persons who had never smoked cigarettes, former smokers, and current smokers at baseline. These results and those from previous studies suggest that beta-carotene is a marker for some protective factor(s) against lung cancer; that cryptoxanthin, alpha-carotene, and ascorbic acid need to be investigated further as potentially protective factors or associates of a protective factor; and that lycopene, alpha-tocopherol, selenium, and peroxyl radical absorption capacity are unlikely to be associated with lung cancer risk. Until specific preventive factors are identified, the best protection against lung cancer is still the avoidance of airborne carcinogens, especially tobacco smoke; second best is the consumption of a diet rich in fruits and vegetables.

Nonmelanoma skin cancer and risk for subsequent malignancy.

BACKGROUND: Individuals with a personal history of nonmelanoma skin cancer (NMSC) may have an increased risk of subsequent noncutaneous malignancies. To test this hypothesis, we carried out a community-based, prospective cohort study. METHODS: In the CLUE (Give Us a Clue to Cancer and Heart Disease) II cohort, which was established in Washington County, MD, in 1989, the risk of new malignancies was compared among individuals with (n = 769) and without (n = 18,405) a personal history of NMSC (total n = 19,174) during a 16-year follow-up period. Pathologically confirmed NMSC (and other malignancies) were ascertained from the Washington County Cancer Registry. Cox regression analysis with time-dependent covariates was used to determine the hazard ratios (presented as multivariable-adjusted relative risks [RRs]) and 95% confidence intervals (CIs) of second primary malignancies associated with a previously confirmed NMSC diagnosis. All statistical tests were two-sided. RESULTS: The crude incidence rate (per 10,000 person-years) of subsequent cancers other than NMSC among participants with a positive personal history of NMSC was 293.5 and with a negative history was 77.8. Compared with persons with no personal history of NMSC, those with such a history had a statistically significantly increased risk of being diagnosed with a subsequent cancer other than NMSC (RR = 1.99, 95% CI = 1.70 to 2.33) after adjusting for age, sex, body mass index, smoking status, and educational level. The association was observed for both basal cell carcinoma (multivariable-adjusted RR = 2.03, 95% CI = 1.70 to 2.42) and squamous cell carcinoma (multivariable-adjusted RR = 1.97, 95% CI = 1.50 to 2.59) of the skin. NMSC was a statistically significantly stronger cancer risk factor in younger age groups than in older age groups (P for interaction = .022). CONCLUSIONS: This community-based, prospective cohort study provides evidence for an association between an NMSC diagnosis and an increased risk of subsequent cancer, even after adjusting for individual-level risk factors.

Non-cancer adverse health conditions and perceived health and function among cancer survivors participating in a community-based cohort study in Washington County, Maryland.

INTRODUCTION: This study was conducted in an ongoing community-based cohort study to examine the prevalence of non-cancer adverse health conditions among cancer survivors and the association of these conditions with self-rated health and functional status. METHODS: Data were analyzed from CLUE II, a community-based cohort study in Washington County, Maryland that began in 1989. Cross-sectional comparisons were made between 1,261 cancer survivors and 1,261 age- and gender-matched individuals without a history of cancer. Information on non-cancer adverse health conditions, self-rated health, and activities of daily living was based on self-report. RESULTS: Compared to individuals without a history of cancer, cancer survivors were significantly more likely to report a diagnosis of cardiovascular disease (33.8% versus 29.8%; p = 0.009) and endocrine disease (other than diabetes) (17.0% versus 14.3%; p = 0.02). Further, cancer survivors reporting two or more non-cancer adverse health conditions had a greater likelihood of reporting fair or poor self-rated health (odds ratio (OR) 4.11; 95% confidence interval (95% CI) 3.06, 5.54), and difficulty with at least one activity of daily living (OR 6.03; 95% CI 4.01, 9.05) compared to cancer survivors who did not report other adverse health conditions. DISCUSSIONS/CONCLUSIONS: Findings from this cross-sectional data analysis indicate that cancer survivors are at increased risk for non-cancer adverse health conditions, which are associated with poorer self-rated health, more interference with normal activities, and functional limitations. IMPLICATIONS FOR CANCER SURVIVORS: Increased attention must be given to the preventive care and treatment of non-cancer adverse health conditions among cancer survivors to decrease non-cancer morbidity and mortality and to maintain and improve quality of life.

A community-based study of cigarette smoking behavior in relation to variation in three genes involved in dopamine metabolism: Catechol-O-methyltransferase (COMT), dopamine beta-hydroxylase (DBH) and monoamine oxidase-A (MAO-A).

OBJECTIVE: Cigarette smoking behavior may be influenced by catechol-O-methlyltransferase (COMT), dopamine beta-hydroxylase (DBH), and monamine oxidase-A (MAO-A), genes that play roles in dopamine metabolism. The association between common polymorphisms of these genes and smoking behavior was assessed among 10,059 Caucasian volunteers in Washington County, MD in 1989. METHODS: Age-adjusted logistic regression was used to measure the association between variants of these single nucleotide polymorphisms and smoking initiation and persistent smoking. RESULTS: Overall, no association was seen between each genotype and smoking behavior. However, among younger (<54 years) women, the COMT GG genotype was positively associated with smoking initiation (OR=1.3; 95% CI: 1.0 1.5), and the MAO-A TT genotype was inversely associated with persistent smoking (OR=0.7; 95% CI: 0.4, 1.0). Men who smoked fewer than 10 cigarettes per day were more likely to be persistent smokers if they had the COMT GG (OR=1.7; 95% CI: 1.0, 2.9) or the DBH GG (OR=1.6; 95% CI: 1.0, 2.5) genotypes. CONCLUSION: Overall the results of this large community-based study do not provide evidence to support the presence of important associations between variants of COMT, DBH, or MAO-A and smoking initiation or persistent smoking.

Single nucleotide polymorphisms in inflammation-related genes and mortality in a community-based cohort in Washington County, Maryland.

The purpose of this study was to examine the associations between single nucleotide polymorphisms (SNPs) in genes controlling inflammatory processes and mortality. Data were analyzed from 9,933 individuals who participated in two large community-based cohort studies conducted in Washington County, Maryland, in 1974 and 1989, designated "CLUE I" and "CLUE II," respectively. DNA from blood collected in 1989 was genotyped for 47 SNPs in 23 inflammation-related genes, including interferon-gamma (IFNgamma), lymphotoxin-alpha (LTalpha), tumor necrosis factor-alpha (TNFalpha), C-reactive protein (CRP), peroxisome proliferator-activated receptor (PPAR), and the human endothelial nitric oxide synthase (eNOS). All participants were followed from 1989 to the date of death or to June 20, 2005. The results showed no observable patterns of association for the SNPs and the all-cause and cause-specific mortality outcomes, although statistically significant associations were observed between at least one mortality outcome and SNPs in eNOS (reference SNP (rs) 1799983), PPARG (rs4684847), CRP (rs2794521), IFNgamma (rs2069705), TNFalpha (rs1799964), and LTalpha (rs2229094). Additionally, three of the four examined CRP SNPs were strongly associated with CRP serum concentration among those with CRP measurements. The authors' findings from this community-based prospective cohort study suggest that the selected SNPs are not associated with overall or cause-specific death, although CRP genotypes may be associated with systemic inflammation.

Body mass, polymorphisms in obesity-related genes, and the risk of developing breast cancer among women with benign breast disease.

BACKGROUND: A cohort study was conducted among post-menopausal women to determine whether genetic polymorphisms in selected obesity-related genes (PPARG, LPL, LEPR, PON1, PON2, TNF-alpha) were associated with the progression of benign breast disease (BBD) to breast cancer and whether the selected polymorphisms modified the association between body mass and breast cancer among women with BBD. METHODS: Among participants in an ongoing cohort study, 994 Caucasian post-menopausal women had a breast biopsy for BBD. Of these women, 61 subsequently developed breast cancer. A short questionnaire was administered at baseline in 1989. Genotypes were determined using DNA extracted from blood collected in 1989. RESULTS: In this cohort, body mass index (BMI) was positively associated with the risk of developing breast cancer. In contrast, polymorphisms in PON1 (Gln192Arg) and LEPR (IVS2+6920) were associated with a decreased risk of developing invasive breast cancer. No statistically significant associations were observed for polymorphisms in PPARG, PON2, LPL, or TNF and breast cancer risk or for interactions between the polymorphisms and BMI and breast cancer risk. CONCLUSIONS: The findings suggest that specific polymorphisms in the PON1 and LEPR genes may play a role in progression of BBD to breast cancer among post-menopausal Caucasian women.

Frequencies of single nucleotide polymorphisms in genes regulating inflammatory responses in a community-based population.

BACKGROUND: Allele frequencies reported from public databases or articles are mostly based on small sample sizes. Differences in genotype frequencies by age, race and sex have implications for studies designed to examine genetic susceptibility to disease. In a community-based cohort of 9,960 individuals, we compared the allele frequencies of 49 single nucleotide polymorphisms (SNPs) of genes involved in inflammatory pathways to the frequencies reported on public databases, and examined the genotypes frequencies by age and sex. The genes in which SNPs were analyzed include CCR2, CCR5, COX1, COX2, CRP, CSF1, CSF2, IFNG, IL1A, IL1B, IL2, IL4, IL6, IL8, IL10, IL13, IL18, LTA, MPO, NOS2A, NOS3, PPARD, PPARG, PPARGC1 and TNF. RESULTS: Mean(SD) age was 53.2(15.5); 98% were Caucasians and 62% were women. Only 1 out of 33 SNPs differed from the SNP500Cancer database in allele frequency by >10% in Caucasians (n = 9,831), whereas 12 SNPs differed by >10% (up to 50%) in African Americans (n = 105). Two out of 15 SNPs differed from the dbSNP database in allele frequencies by >10% in Caucasians, and 5 out of 15 SNPs differed by >10% in African Americans. Age was similar across most genotype groups. Genotype frequencies did not differ by sex except for TNF(rs1799724), IL2(rs2069762), IL10(rs1800890), PPARG(rs1801282), and CRP(rs1800947) with differences of less than 4%. CONCLUSION: When estimating the size of samples needed for a study, particularly if a reference sample is used, one should take into consideration the size and ethnicity of the reference sample. Larger sample size is needed for public databases that report allele frequencies in non-Caucasian populations.

Nonsteroidal anti-inflammatory drugs and the risk of developing breast cancer in a population-based prospective cohort study in Washington County, MD.

The objective of this study was to examine the association between nonsteroidal anti-inflammatory drug (NSAID) use and the development of breast cancer, and to assess whether this association differed by estrogen receptor (ER) subtype. Data were analyzed from 15,651 women participating in CLUE II, a cohort study initiated in 1989 in Washington County, MD. Medication data were collected at baseline in 1989 and in 1996. Incident cases of invasive breast cancer occurring from baseline to March 27, 2006 were identified through linkage of cohort participants with the Washington County Cancer Registry and the Maryland State Cancer Registry. Cox proportional hazards modeling was used to calculate the risk ratios (RR) and 95% confidence intervals (95% CI) for breast cancer associated with medication use. Among women in the CLUE II cohort, 418 invasive breast cancer cases were identified during the follow-up period. The results showed that self-reported use of NSAIDs in both 1989 and in 1996 was associated with a 50% reduction in the risk of developing invasive breast cancer compared with no NSAID use in either 1989 or 1996 (RR = 0.50; 95% CI 0.28, 0.91). The protective association between NSAID use and the risk of developing breast cancer was consistent among ER-positive and ER-negative breast cancers, although only the RR for ER-positive breast cancer was statistically significant. Overall, findings from this study indicate that NSAID use is associated with a decrease in breast cancer risk and that the reduction in risk is similar for ER-positive and ER-negative tumors.

Meat and dairy consumption and subsequent risk of prostate cancer in a US cohort study.

OBJECTIVE: To evaluate the association of meat and dairy food consumption with subsequent risk of prostate cancer. METHODS: In 1989, 3,892 men 35+ years old, who participated in CLUE II study of Washington County, MD, completed an abbreviated Block food frequency questionnaire. Intake of meat and dairy related foods was calculated using consumption frequency and portion size. Incident prostate cancer cases (n = 199) were ascertained through October 2004. Cox proportional hazards regression was used to calculate hazard ratios (HR) of total and advanced (SEER states three and four; n = 54) prostate cancer and 95% confidence intervals (CI) adjusted for age, BMI at age 21, and intake of energy, saturated fat, and tomato products. RESULTS: Intakes of total mean (HR = 0.90, 95% CI 0.60-1.33, comparing highest to lowest tertile) and red meat (HR = 0.87, 95% CI 0.59-1.32) were not statistically significantly associated with prostate cancer. However, processed meat consumption was associated with a non-statistically significant higher risk of total (5+ vs. < or =1 servings/week: HR = 2.24; 95% CI 0.90-5.59) prostate cancer. There was no association across tertiles of dairy or calcium with total prostate cancer, although compared tp < or =1 servings/week consumption of 5+ servings/week of dairy foods was associated with an increased risk of prostate cancer (HR = 1.65, 98% CI 1.02-2.66). CONCLUSION: Overall, consumption of processed meat, but not total meat or red meat, was associated with a possible increased risk of total prostate cancer in this prospective study. Higher intake of dairy foods but not calcium was positively associated with prostate cancer. Further investigation into the mechanisms by which processed meat and dairy consumption might increase the risk of prostate cancer is suggested.

Alcohol dehydrogenase genetic polymorphisms, low-to-moderate alcohol consumption, and risk of breast cancer.

BACKGROUND: In vitro, human isoenzymes encoded by genes homozygous for the ADH1C*1 or ADH1B*2 alleles metabolize ethanol to acetaldehyde at a faster rate than those homozygous for the ADH1C*2 or ADH1B*1 allele. Because alcohol is a known risk factor for breast cancer, we evaluated the joint association of genetic variants in ADH and alcohol consumption in relation to breast cancer. METHODS: A nested case-control study of 321 cases and matched controls was conducted. Five single nucleotide polymorphisms (SNPs) in the ADH1C and ADH1B genes were genotyped. Logistic regression was used to assess odds ratios (ORs) and 95% confidence limits (CIs) for each SNP. Haplotype analysis of all 5 SNPs was also undertaken. RESULTS: Among drinkers, the median intake of total alcohol was 13 g/wk (10th-90th percentiles; 4.5-135.9) in cases and 18 g/wk (10th-90th percentiles; 4.5-104.1) in controls. Women who drank alcohol tended to be at an increased risk of developing breast cancer compared with those who did not drink (OR=1.40%, 95% CI 0.97-2.03), particularly those who were premenopausal at the time of breast cancer diagnosis (OR=2.69%, 95% CI: 1.00-7.26). Of the known functional alleles, breast cancer risk was not significantly increased among carriers of at least 1 ADH1C*1 or ADH1B*2 allele, when compared with those homozygous for the genotype at each locus. However, breast cancer risk tended to be lower among women who inherited the G allele at ADH1B IVS1+896A>G (OR=0.62, 95% CI 0.37-1.04). Overall haplotype frequencies were not significantly different between cases and controls. CONCLUSIONS: In this study low levels of alcohol are associated with a modest increase in breast cancer risk that is not altered by known functional allelic variants of the ADH1B and 1C gene. The protective association conferred by the G allele at ADH1B IVS1+896A>G needs further evaluation.

A prospective cohort study of bladder cancer risk in relation to active cigarette smoking and household exposure to secondhand cigarette smoke.

Active cigarette smoking is a major risk factor for bladder cancer. Secondhand exposure to cigarette smoke may also contribute to bladder carcinogenesis. The authors conducted a prospective cohort study to examine the influence of both active smoking and household exposure to secondhand smoke (SHS) on subsequent bladder cancer risk. The study population included persons from two cohorts established from private censuses conducted in Washington County, Maryland, in 1963 (n = 45,749; 93 cases) and 1975 (n = 48,172; 172 cases). Poisson regression models were fitted to estimate the relative risk of bladder cancer associated with active and passive smoke exposure in the two cohorts (referent category: never smokers who did not live with any smokers). Current smokers had an elevated risk of bladder cancer in both the 1963 cohort (relative risk (RR) = 2.7, 95% confidence limits (CL): 1.6, 4.7) and the 1975 cohort (RR = 2.6, 95% CL: 1.7, 3.9) after adjustment for age, education, and marital status. Among nonsmoking women, current household SHS exposure was associated with bladder cancer risk in the 1963 cohort (RR = 2.3, 95% CL: 1.0, 5.4) but not in the 1975 cohort (RR = 0.9, 95% CL: 0.4, 2.3). This study further solidifies the evidence that active smoking is causally associated with bladder cancer. Additional studies are needed to determine whether passive smoking is a risk factor for bladder cancer.

Mismatch repair polymorphisms and the risk of colorectal cancer.

Rare germline variants in mismatch repair genes have been linked to hereditary nonpolyposis colorectal cancer; however, it is unknown whether common polymorphisms in these genes alter the risk of colorectal cancer. To examine the association between common variants in mismatch repair genes and colorectal cancer, we conducted a case-cohort study within the CLUE II cohort. Four single nucleotide polymorphisms in 3 mismatch repair genes (MSH3 R940Q, MSH3 T1036A, MSH6 G39E and MLH1 I219V) were genotyped in 237 colorectal cancer cases and a subcohort of 2,189 participants. Incidence rate ratios (RRs) and 95% confidence intervals (95% CIs) for each polymorphism were estimated. The MSH3 1036A variant was found to be associated with an increased risk of colorectal cancer (RR=1.28, 95% CI: 0.94-1.74 and RR=1.65, 95% CI: 1.01-2.70 for the AT and TT genotypes, respectively, with p(trend)=0.02), particularly proximal colon cancer. Although the MSH3 940Q variant was only weakly associated with colorectal cancer overall (p(trend)=0.07), it was associated with a significant increased risk of proximal colon cancer (RR=1.69, 95% CI: 1.10-2.61 and RR=2.68, 95% CI: 0.96-7.47 for the RQ and QQ genotypes, respectively with p(trend)=0.005). Processed meat intake appeared to modify the association between the MSH3 polymorphisms and colorectal cancer (p(interaction) < 0.10 for both). No association was observed with the MSH6 and MLH1 polymorphisms overall. This study suggests that common polymorphisms in the mismatch repair gene, MSH3, may increase the risk of colorectal cancer, especially proximal colon cancer.

Genetic variation in the nucleotide excision repair pathway and colorectal cancer risk.

Nucleotide excision repair (NER) enzymes are critical for the removal of bulky DNA adducts caused by environmental carcinogens, such as heterocyclic amines and polycyclic aromatic hydrocarbons, which are found in two putative risk factors for colorectal cancer, tobacco smoke and meat cooked at high temperature. To examine the association between common genetic variants in NER genes and the risk of colorectal cancer, we conducted a case-cohort study within the CLUE II cohort. Twenty-two single nucleotide polymorphisms in 11 NER genes were genotyped in 250 colorectal cancer cases and a subcohort of 2,224 participants. Incidence rate ratios (RR) and 95% confidence intervals (95% CI) were estimated using a modified Cox regression model and robust variance estimate. The ERCC6 1213G variant, which is thought to reduce NER capacity, was associated with an increased risk of colorectal cancer compared with the homozygous wild type (RR, 1.36; 95% CI, 1.00-1.86 and RR, 2.64; 95% CI, 1.53-4.58 for the RG and GG genotypes respectively with P(trend) = 0.0006). Having at least one XPC 492H allele was also associated with an increased risk of colorectal cancer (RR, 1.75; 95% CI, 1.20-2.57). When the combined effects of ERCC6 R1213G and XPC R492H were examined, the risk of colorectal cancer significantly increased with increasing number of variant alleles (P(trend) = 0.00003). Our study suggests that genetic polymorphisms in the NER genes, ERCC6 and XPC, may be associated with an increased risk of colorectal cancer.