Association of urinary biomarkers of tobacco exposure with lung cancer risk in African American and White cigarette smokers in the Southern Community Cohort Study

BACKGROUND

After accounting for smoking history lung cancer incidence is greater in African Americans than Whites. In the Multiethnic Cohort, total nicotine equivalents (TNE) are higher in African Americans than Whites at similar reported cigarettes per day (CPD). Greater toxicant uptake per cigarette may contribute to the greater lung cancer risk of African Americans.

METHODS

In a nested case-control lung cancer study within the Southern Community Cohort, smoking-related biomarkers were measured in 259 cases and 503 controls (40% White, 56% African American). TNE, the trans-3-hydroxycotinine:cotinine ratio, 4-(methylnitrosamino)-1-3-(pyridyl)-1-butanol (NNAL), mercapturic acid metabolites of volatile organic compounds, phenanthrene metabolites, cadmium, and (Z)-7-(1R,2R,3R,5S)-3,5-dihydroxy-2-[(E,3S)-3-hydroxyoct-1-enyl]cyclopenyl]hept-5-enoic acid (8-iso-PGF2α) were quantified in urine. Unconditional logistic regression was used to estimate the odds ratios and 95% confidence intervals for each biomarker and lung cancer risk.

RESULTS

TNE, NNAL and cadmium were higher in cases than controls (adjusted for age, race, sex, body mass index (BMI) and CPD). Among cases, these levels were higher in African Americans compared to Whites. After accounting for age, sex, BMI and pack-years, a one-SD increase in log-TNE (OR=1.30; 95% CI: 1.10-1.54) and log-NNAL (OR=1.27; 95% CI: 1.03-1.58 with TNE adjustment) were associated with lung cancer risk. In this study, where NNAL concentration is relatively high, the association for log-TNE was attenuated after adjustment for log-NNAL.

CONCLUSION

Smoking-related biomarkers provide additional information for lung cancer risk in smokers beyond smoking pack-years.

IMPACT

Urinary NNAL, TNE and cadmium concentrations in current smokers, particularly African American smokers, may be useful for predicting lung cancer risk.

Genome-wide association study of abdominal MRI-measured visceral fat: The multiethnic cohort adiposity phenotype study

Few studies have explored the genetic underpinnings of intra-abdominal visceral fat deposition, which varies substantially by sex and race/ethnicity. Among 1,787 participants in the Multiethnic Cohort (MEC)-Adiposity Phenotype Study (MEC-APS), we conducted a genome-wide association study (GWAS) of the percent visceral adiposity tissue (VAT) area out of the overall abdominal area, averaged across L1-L5 (%VAT), measured by abdominal magnetic resonance imaging (MRI). A genome-wide significant signal was found on chromosome 2q14.3 in the sex-combined GWAS (lead variant rs79837492: Beta per effect allele = -4.76; P = 2.62 × 10-8) and in the male-only GWAS (lead variant rs2968545: (Beta = -6.50; P = 1.09 × 10-9), and one suggestive variant was found at 13q12.11 in the female-only GWAS (rs79926925: Beta = 6.95; P = 8.15 × 10-8). The negatively associated variants were most common in European Americans (T allele of rs79837492; 5%) and African Americans (C allele of rs2968545; 5%) and not observed in Japanese Americans, whereas the positively associated variant was most common in Japanese Americans (C allele of rs79926925, 5%), which was all consistent with the racial/ethnic %VAT differences. In a validation step among UK Biobank participants (N = 23,699 of mainly British and Irish ancestry) with MRI-based VAT volume, both rs79837492 (Beta = -0.026, P = 0.019) and rs2968545 (Beta = -0.028, P = 0.010) were significantly associated in men only (n = 11,524). In the MEC-APS, the association between rs79926925 and plasma sex hormone binding globulin levels reached statistical significance in females, but not in males, with adjustment for total adiposity (Beta = -0.24; P = 0.028), on the log scale. Rs79837492 and rs2968545 are located in intron 5 of CNTNAP5, and rs79926925, in an intergenic region between GJB6 and CRYL1. These novel findings differing by sex and racial/ethnic group warrant replication in additional diverse studies with direct visceral fat measurements.

Genetic diversity fuels gene discovery for tobacco and alcohol use

Tobacco and alcohol use are heritable behaviours associated with 15% and 5.3% of worldwide deaths, respectively, due largely to broad increased risk for disease and injury1-4. These substances are used across the globe, yet genome-wide association studies have focused largely on individuals of European ancestries5. Here we leveraged global genetic diversity across 3.4 million individuals from four major clines of global ancestry (approximately 21% non-European) to power the discovery and fine-mapping of genomic loci associated with tobacco and alcohol use, to inform function of these loci via ancestry-aware transcriptome-wide association studies, and to evaluate the genetic architecture and predictive power of polygenic risk within and across populations. We found that increases in sample size and genetic diversity improved locus identification and fine-mapping resolution, and that a large majority of the 3,823 associated variants (from 2,143 loci) showed consistent effect sizes across ancestry dimensions. However, polygenic risk scores developed in one ancestry performed poorly in others, highlighting the continued need to increase sample sizes of diverse ancestries to realize any potential benefit of polygenic prediction.

Abstract PO-258: Disparities in eligibility for low-dose CT (LDCT) lung cancer screening among a multiethnic population

Introduction: African Americans and Native Hawaiians have a higher risk of lung cancer and greater mortality rate than other racial/ethnic groups in the US. The guidelines for lung cancer screening by low-dose CT scan were derived from clinical trial data conducted primarily in white men. In 2021, to address the underlying ethnic/racial disparities in eligibility for lung cancer screening the United States Preventive Services Task Force (USPSTF) updated the 2013 guidelines from 55-80 years of age, current or former smokers (quit ≤15 years) with a 30 pack-year smoking history to include ever smokers ≥50 years of age and with a ≥20 pack-year history. We hypothesize that the disparities in eligibility across race/ethnicity will remain due to the greater age-specific risk and lower pack-years among African Americans and Native Hawaiians. Methods: We used the Multiethnic Cohort study (MEC) data to examine ineligibility to both USPSTF guidelines by sex and race/ethnicity among 1,761 incident lung cancer cases diagnosed within 7 years of study entry. This analysis included African and Japanese Americans, Latino, Native Hawaiians and whites. Smoking history was collected by a self-administered questionnaire at cohort entry. The difference in proportion of ineligible for each group compared to whites were assessed. Results: Among the 1,042 men and 719 women with incident lung cancer, under the 2013 guidelines, 54% of men and 70% of women would have been ineligible for lung cancer screening. Under the 2021 guidelines, 41% of men and 59% of women would have been eligible. For the 2013 guidelines, in men, the disparity was highest in Latinos (19% difference compared to whites), followed by Native Hawaiians (18%), and African (17%) and Japanese (9%) Americans. In women, the disparity was highest in African Americans (33%), followed by Latinas (25%), Japanese Americans (25%), and Native Hawaiians (13%). While an additional ~12% of overall lung cancer cases would have been eligible for screening using the updated guidelines, the disparity in eligibility compared to whites for each racial/ethnic group remained similar (range: 9% in Japanese American men to 33% in African American women). Eleven percent of men and 28% of women would have been ineligible for never smoking. Among ineligible ever smokers, more non-whites than whites were ineligible due to the 20 pack-year threshold (men: 77% vs 64% and women: 90% vs 76%). Also, while an overall 8% of both men and women would have been ineligible due to the age threshold, >20% of Native Hawaiian cases were ineligible due to age. Conclusions: Our findings demonstrate that despite the lower thresholds in the smoking history and age criteria in the updated USPSTF guidelines, racial/ethnic disparities in lung cancer screening eligibility remains. Reasons for these differences include a lower smoking pack-year history and greater age-specific risk among ever smokers, and a higher proportion of never smoker lung cancer cases. Additional analyses with cumulative smoking history are in progress.

Citation Format: S. Lani Park, Kyla Yamashita, Lenora Loo, Daniel Stram, Yurii Shvetsov, Loic Le Marchand. Disparities in eligibility for low-dose CT (LDCT) lung cancer screening among a multiethnic population [abstract]. In: Proceedings of the AACR Virtual Conference: 14th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2021 Oct 6-8. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2022;31(1 Suppl):Abstract nr PO-258.

The Genomics of Young Lung Cancer: Comprehensive Tissue Genomic Analysis in Patients Under 40 With Lung Cancer

Introduction

Lung adenocarcinomas in young patients (<40 y) are more likely to harbor targetable genomic alterations. This study aimed to determine whether the prevalence of targetable alterations is greater in young adults with lung carcinoma than in the overall lung cancer population. To reach this rare patient population, a web-based platform was used to recruit and enroll patients remotely.

Methods

In this prospective study, patients less than 40 years old at the time of primary lung cancer diagnosis with confirmed lung carcinoma were recruited from four global sites and remotely by means of a website. Genotyping data were collected, if available, or obtained by means of next-generation sequencing using the FoundationOne platform. The prevalence of targetable alterations was quantified across patients with advanced adenocarcinoma.

Results

Overall, 133 patients across five continents were included, 41% of whom enrolled online. The mean (SD) age at diagnosis was 34 (5.2) years; 79% had stage IV disease at diagnosis. Among patients with adenocarcinoma (n = 115), 112 entered the study with previous genomic testing results and 86 (77%) had targetable alterations in EGFR, ALK, ROS1, MET, ERBB2, or RET. Among those without targetable alterations, 14 received further testing and a targetable alteration was identified in eight (57%).

Conclusions

This study revealed the feasibility of using a web-based platform to recruit young patients with lung cancer and revealed that 94 of 112 (84%) with adenocarcinoma at any stage had targetable genomic alterations. Among patients with stage IV adenocarcinoma, 85% had a targetable alteration, which is higher than historical expectations for the general population.

Genome-wide association study of pancreatic fat: The Multiethnic Cohort Adiposity Phenotype Study

Several studies have found associations between higher pancreatic fat content and adverse health outcomes, such as diabetes and the metabolic syndrome, but investigations into the genetic contributions to pancreatic fat are limited. This genome-wide association study, comprised of 804 participants with MRI-assessed pancreatic fat measurements, was conducted in the ethnically diverse Multiethnic Cohort-Adiposity Phenotype Study (MEC-APS). Two genetic variants reaching genome-wide significance, rs73449607 on chromosome 13q21.2 (Beta = -0.67, P = 4.50x10-8) and rs7996760 on chromosome 6q14 (Beta = -0.90, P = 4.91x10-8) were associated with percent pancreatic fat on the log scale. Rs73449607 was most common in the African American population (13%) and rs79967607 was most common in the European American population (6%). Rs73449607 was also associated with lower risk of type 2 diabetes (OR = 0.95, 95% CI = 0.89-1.00, P = 0.047) in the Population Architecture Genomics and Epidemiology (PAGE) Study and the DIAbetes Genetics Replication and Meta-analysis (DIAGRAM), which included substantial numbers of non-European ancestry participants (53,102 cases and 193,679 controls). Rs73449607 is located in an intergenic region between GSX1 and PLUTO, and rs79967607 is in intron 1 of EPM2A. PLUTO, a lncRNA, regulates transcription of an adjacent gene, PDX1, that controls beta-cell function in the mature pancreas, and EPM2A encodes the protein laforin, which plays a critical role in regulating glycogen production. If validated, these variants may suggest a genetic component for pancreatic fat and a common etiologic link between pancreatic fat and type 2 diabetes.

Ethnic differences in excretion of butadiene-DNA adducts by current smokers

1,3-Butadiene (BD) is a known human carcinogen used in the synthetic polymer industry and also found in cigarette smoke, automobile exhaust and wood burning smoke. BD is metabolically activated by cytochrome P450 monooxygenases (CYP) 2E1 and 2A6 to 3,4-epoxy-1-butene (EB), which can be detoxified by GST-catalyzed glutathione conjugation or hydrolysis. We have previously observed ethnic differences in urinary levels of EB-mercapturic acids in white, Japanese American and Native Hawaiian smokers. In the present study, similar analyses were extended to urinary BD-DNA adducts. BD-induced N7-(1-hydroxy-3-buten-2-yl) guanine (EB-GII) adducts were quantified in urine samples obtained from smokers and non-smokers belonging to three racial/ethnic groups: white, Japanese American and Native Hawaiian. After adjusting for sex, age, nicotine equivalents, body mass index and batch, we found that Japanese American smokers excreted significantly higher amounts of urinary EB-GII than whites [1.45 (95% confidence interval: 1.12-1.87) versus 0.68 (95% confidence interval: 0.52-0.85) fmol/ml urine, P = 4 × 10-5]. Levels of urinary EB-GII in Native Hawaiian smokers were not different from those in whites [0.67 (95% confidence interval: 0.51-0.84) fmol/ml urine, P = 0.938]. There were no racial/ethnic differences in urinary EB-GII adduct levels in non-smokers. Racial/ethnic differences in urinary EB-GII adduct levels in smokers could not be explained by GSTT1 gene deletion or CYP2A6 enzymatic activity. Urinary EB-GII adduct levels in smokers were significantly associated with concentrations of BD metabolite dihyroxybutyl mercapturic acid. Overall, our results reveal that urinary EB-GII adducts in smokers differ across racial/ethnic groups. Future studies are required to understand genetic and epigenetic factors that may be responsible for these differences.

Genome-Wide Association Study of Liver Fat: The Multiethnic Cohort Adiposity Phenotype Study

The global rise in fatty liver is a major public health problem. Thus, it is critical to identify both global and population-specific genetic variants associated with liver fat. We conducted a genome-wide association study (GWAS) of percent liver fat and nonalcoholic fatty liver disease (NAFLD) assessed by magnetic resonance imaging in 1,709 participants from the population-based Multiethnic Cohort Adiposity Phenotype Study. Our participants comprised older adults of five U.S. racial/ethnic groups: African Americans (n = 277), Japanese Americans (n = 424), Latinos (n = 348), Native Hawaiians (n = 274), and European Americans (n = 386). The established missense risk variant rs738409 located in patatin-like phospholipase domain containing 3 (PNPLA3) at 22q13 was confirmed to be associated with percent liver fat (P = 3.52 × 10-15) but more strongly in women than men (P heterogeneity = 0.002). Its frequency correlated with the prevalence of NAFLD across the five ethnic/racial groups. Rs738409 was also associated with homeostasis model assessment of insulin resistance (HOMA-IR) (beta = 0.028; P = 0.009) and circulating levels of insulin (beta = 0.022; P = 0.020) and alanine aminotransferase (beta = 0.016; P = 0.030). A novel association of percent liver fat with rs77249491 (located at 6q13 between limb region 1 domain containing 1 [LMBRD1] and collagen type XIX alpha 1 chain [COL19A1] (P = 1.42 × 10-8) was also observed. Rs7724941 was associated with HOMA-IR (beta = 0.12; P = 0.0005), insulin (beta = 0.11; P = 0.0003), triglycerides (beta = 0.059; P = 0.01), high-density lipoprotein (beta = -0.046; P = 0.04), and sex hormone binding globulin (beta = -0.084; P = 0.0012). This variant was present in Japanese Americans (minor allele frequency [MAF], 8%) and Native Hawaiians (MAF, 2%). Conclusion: We replicated the PNPLA3 rs738409 association in a multiethnic population and identified a novel liver fat risk variant in Japanese Americans and Native Hawaiians. GWASes of percent liver fat in East Asian and Oceanic populations are needed to replicate the rs77249491 association.

Racial/Ethnic Differences in Lung Cancer Incidence in the Multiethnic Cohort Study: An Update

BACKGROUND

We previously found that African Americans and Native Hawaiians were at highest lung cancer risk compared with Japanese Americans and Latinos; whites were midway in risk. These differences were more evident at relatively low levels of smoking intensity, fewer than 20 cigarettes per day (CPD), than at higher intensity.

METHODS

We apportioned lung cancer risk into three parts: age-specific background risk (among never smokers), an excess relative risk term for cumulative smoking, and modifiers of the smoking effect: race and years-quit smoking. We also explored the effect of replacing self-reports of CPD with a urinary biomarker-total nicotine equivalents-using data from a urinary biomarker substudy.

RESULTS

Total lung cancers increased from 1979 to 4993 compared to earlier analysis. Estimated excess relative risks for lung cancer due to smoking for 50 years at 10 CPD (25 pack-years) ranged from 21.9 (95% CI = 18.0 to 25.8) for Native Hawaiians to 8.0 (95% CI = 6.6 to 9.4) for Latinos over the five groups. The risk from smoking was higher for squamous cell carcinomas and small cell cancers than for adenocarcinomas. Racial differences consistent with earlier patterns were seen for overall cancer and for cancer subtypes. Adjusting for predicted total nicotine equivalents, Japanese Americans no longer exhibit a lower risk, and African Americans are no longer at higher risk, compared to whites. Striking risk differences between Native Hawaiians and Latinos persist.

CONCLUSIONS

Racial differences in lung cancer risk persist in the Multiethnic Cohort study that are not easily explained by variations in self-reported or urinary biomarker-measured smoking intensities.

Abstract C048: Multiethnic polygenic risk scores and smoking interactions for chronic obstructive lung disease

Background: Chronic obstructive pulmonary disease (COPD) is the third leading cause of death in the US with differential risk across race/ethnicity groups and increases lung cancer risk. In the Multiethnic Cohort (MEC), an ethnically diverse prospective cohort (&gt;215,000) established in the early 1990’s in California and Hawaii, we found COPD prevalence was highest in African Americans, followed by European Americans, Native Hawaiians, Latinos and Japanese Americans. Family history and smoking are strong risk factors for COPD with heritability estimates ranging from 20-40%. However, large scale genomic studies (GWAS) have primarily focused on Europeans. Thus, ethnic-specific calibration of polygenic risk scores (PRS) for predicting COPD has the potential to identify those with greatest need for recommended screening and targeted prevention. Methods: Incident COPD case status was identified from linkage to Medicare claims files which followed a total of 17,291 for PRS analyses from 1998-2014. We performed Cox regression accounting for pack-years smoked and duration quit at two time points of 3,917 COPD cases with genetic data. Genotyped data from MEC individuals from multiple SNP arrays were imputed to the Haplotype Reference Consortium panel (~39 million SNPs). From this repository, we extracted 82 independent risk loci identified from the largest (250,000 European individuals) lung function/COPD GWAS to date from the UK Biobank. To calculate the COPD PRS, we matched imputed dosages to the 82 reported UK Biobank risk allele by locus and summed MEC genotypes under a standard additive general linear model. We compared two Cox regression models 1) not including PRS and 2) including PRS. Results: From epidemiologic analysis, we find that smoking is highly predictive of COPD risk (as expected) and that even after adjusting for pack-years of smoking and years quit racial disparities are evident, with African Americans (Hazard Ratio (HR): 1.25, p=3.7 × 10−6) and Japanese Americans (HR: 1.14, p=0.017) having slightly increased risk of disease compared to European Americans; whereas, Native Hawaiians have similar risk as European Americans (HR=0.95, p=0.48) and Latinos have decreased risk (HR: 0.75, p=2.43 × 10−8). Testing the PRS, we found an 8% increase risk per standard deviation (HR:1.08, p=5.41 × 10−6) while ethnic group differences in risk remained quite similar after adjustment for the PRS. Testing for interaction between pack-years and PRS, we found a suggestive increase of the smoking effect for those with the highest levels of PRS (p=0.09). Conclusion: Based on the racial disparities present from our COPD findings, particularly the increased risks among African Americans and Japanese Americans, we will examine the excess relative risk over a lifetime and within 5-year age intervals. We are currently expanding our MEC genotyped repository which should double our sample size, improve ability to detect PRS-smoking interactions, as well as test PRS for lung cancer.

Citation Format: Linda M. Polfus, Meng Lin, S. Lani Park, David Conti, Jackie Porcel, Veronica W. Setiawan, Lynne Wilkens, Christopher A. Haiman, Loïc Le Marchand, Daniel O. Stram. Multiethnic polygenic risk scores and smoking interactions for chronic obstructive lung disease [abstract]. In: Proceedings of the Twelfth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2019 Sep 20-23; San Francisco, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl_2):Abstract nr C048.

Abstract C052: Association between benzene, a hazardous air pollutant, and lung cancer risk: The Multiethnic Cohort Study

Background: Benzene is classified as a Group 1 carcinogen in humans. A major pathway of benzene exposure is through inhalation of ambient air contaminated by emissions from motor vehicle exhaust, gas stations, industry, tobacco smoke, and other consumer products. Prior studies of benzene and lung cancer have been limited largely to occupational studies. We examined the association between outdoor air exposure to benzene and lung cancer risk in the large population-based Multiethnic Cohort Study (MEC), including four major U.S. racial/ethnic groups—African Americans, Latinos, Japanese Americans, and Whites. Methods: Ambient benzene exposure was estimated from EPA data from air monitoring stations that were within 20 km of residences of 97,288 MEC participants, largely from Los Angeles County, from the time-period of recruitment (1993-1996) through 12/31/2013. Cox proportional hazards models were used to examine the associations between time-varying benzene exposure and lung cancer risk (cases=2796), adjusting for age, sex, race/ethnicity, smoking, family history of lung cancer, marital status, education, occupation, use of nonsteroidal anti-inflammatory drugs, body mass index, alcohol consumption, physical activity, intake of total calorie, red and processed meats, and neighborhood (block group) socioeconomic status. Stratified analyses were conducted by sex, race/ethnicity, and smoking status. In addition, subgroup analysis was conducted by histologic cell-type (adenocarcinoma, squamous cell carcinoma, small cell carcinoma, large cell, and not otherwise specified carcinoma). Results: Ambient benzene exposure was associated with increased risk of lung cancer (per 1 ppb hazard ratio (HR)=1.18; 95% CI: 1.03-1.35). Slightly higher hazard ratios were observed in females (HR=1.28; 95% CI: 1.05-1.56) in comparison to males (HR=1.12; 95% CI: 0.92-1.35). There was evidence of heterogeneity in associations by race/ethnicity (p heterogeneity=0.02). Specifically, benzene exposure was associated with increased lung cancer risk among African Americans, Japanese Americans, and Latinos (HR ranged 1.18 to 1.42 per 1 ppb), but was inversely associated with risk among Whites. Also, similar associations were seen among ever smokers (HR=1.19; 95% CI: 1.03-1.37) and never smokers (HR=1.25; 95% CI: 0.82-1.89). Across histologic-cell types, a borderline statistically significant association was seen with adenocarcinoma, the most common cell type (HR=1.25, 95% CI: 0.99-1.58). A smaller hazard ratio was observed for squamous cell carcinoma, the stronger smoking-related cell type (HR=1.09, 95% CI: 0.81-1.47). Conclusions: Benzene exposure adversely impacts the risk of lung cancer in the general population but particularly in non-Whites after adjusting for smoking, occupational and other exposures. Additional large population-based studies are needed to confirm this finding and reinforce the need for stringent clear air laws.

Citation Format: Iona Cheng, Chiuchen Tseng, Jun Wu, Juan Yang, Salma Shariff-Marco, Jennifer Jain, S. Lani Park, Scott Fruin, Timothy Larson, Scarlett Lin Gomez, Lynne Wilkens, Daniel Stram, Loic Le Marchand, Beate Ritz, Anna H Wu. Association between benzene, a hazardous air pollutant, and lung cancer risk: The Multiethnic Cohort Study [abstract]. In: Proceedings of the Twelfth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2019 Sep 20-23; San Francisco, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl_2):Abstract nr C052.

Genetics of Chronic Kidney Disease Stages Across Ancestries: The PAGE Study

Background

Chronic kidney disease (CKD) is common and disproportionally burdens United States ethnic minorities. Its genetic determinants may differ by disease severity and clinical stages. To uncover genetic factors associated CKD severity among high-risk ethnic groups, we performed genome-wide association studies (GWAS) in diverse populations within the Population Architecture using Genomics and Epidemiology (PAGE) study.

Methods

We assembled multi-ethnic genome-wide imputed data on CKD non-overlapping cases [4,150 mild to moderate CKD, 1,105 end-stage kidney disease (ESKD)] and non-CKD controls for up to 41,041 PAGE participants (African Americans, Hispanics/Latinos, East Asian, Native Hawaiian, and American Indians). We implemented a generalized estimating equation approach for GWAS using ancestry combined data while adjusting for age, sex, principal components, study, and ethnicity.

Results

The GWAS identified a novel genome-wide associated locus for mild to moderate CKD nearby NMT2 (rs10906850, p = 3.7 × 10^-8) that replicated in the United Kingdom Biobank white British (p = 0.008). Several variants at the APOL1 locus were associated with ESKD including the APOL1 G1 rs73885319 (p = 1.2 × 10^-9). There was no overlap among associated loci for CKD and ESKD traits, even at the previously reported APOL1 locus (p = 0.76 for CKD). Several additional loci were associated with CKD or ESKD at p-values below the genome-wide threshold. These loci were often driven by variants more common in non-European ancestry.

Conclusion

Our genetic study identified a novel association at NMT2 for CKD and showed for the first time strong associations of the APOL1 variants with ESKD across multi-ethnic populations. Our findings suggest differences in genetic effects across CKD severity and provide information for study design of genetic studies of CKD in diverse populations.

Abstract 232: Genome-wide association study (GWAS) of total nicotine equivalents: A composite biomarker of nicotine uptake

The primary risk factor for lung cancer (second most common cancer in men and women in the U.S.) is tobacco smoking. Prior GWAS have identified variants in the CHRNA5-CHRNA3-CHRNB4 cluster (chr 15q25) to be associated with smoking. Total nicotine equivalents (TNE) measured from urine represents the sum of nicotine, cotinine, and trans-3′-hydroxycotinine and its glucuronides, as well as nicotine N-oxide, and is a biomarker of nicotine uptake and, when adjusted for cigarettes smoked per day (CPD), a biomarker of smoking intensity. In addition to smoking status, genetic variation is likely to influence smoking behavior (e.g., number of cigarettes, number of puffs, depth of inhalation) and, thus, one's internal exposure to nicotine and tobacco carcinogens. We conducted a genome-wide association study of TNE (i.e. smoking dose) among 2,239 cancer-free, current smokers from the Multiethnic Cohort, comprised of 5 ethnic groups. TNE was measured using liquid chromatography-tandem mass spectrometry analysis in overnight or first morning urine samples. Genotyping was conducted utilizing the Illumina 1M array and the data were imputed to the 1000 Genomes reference panel, for a total of 11.9 million SNPs and indels. Linear regression models were conducted in all subjects combined and each ethnic group using the log transformed TNE measurement, adjusted for age, BMI, sex, and the first ten principle components (Model 1). A separate model additionally adjusted for log transformed cigarettes per day (Model 2). Genome-wide significant associations with TNE for Model 1 included the chr 15q25 region, specifically, intronic common SNPs in CHRNB4 (rs17487223) and CHRNA3 (rs55676755) with P=7.37x10-9 (Beta (SE) = 0.21 (0.04)) and P=2.22x10-8 (Beta (SE) = 0.19 (0.03)), respectively. Ethnic specific analyses pointed to European American, African American, and Hispanic individuals mainly contributing to the signal. Nicotinic receptors, as ligand-gated channels consist of five subunits and are the primary targets for nicotine and initiate the brain responses to smoking. Our findings with nicotine uptake confirm previous reports that these biologically plausible genes influence smoking behavior. For Model 2 in all pooled ethnicities combined, three intronic SNPs were near genome-wide significance (with lowest P=7.13x10-8 for rs55934265) in the beta-1,3-galactosyltransferase (B3GALT1) gene, Beta (SE) = -0.57 (0.10). The B3GALT1 signal was primarily driven by the African American data (N=364) with ethnic specific results at P=5.3x10-4, Beta (SE) = -0.47 (0.13). B3GALT1 is expressed exclusively in the brain and is involved in the biosynthesis of glycolipids. Next steps include constructing a genetic risk score (GRS) of TNE, and evaluating the GRS in association with lung cancer risk independent of self-reported levels of smoking.

Citation Format: Linda M. Polfus, S. Lani Park, Yesha M. Patel, Sharon E. Murphy, David Conti, Christopher Haiman, Daniel O. Stram, Loïc Le Marchand. Genome-wide association study (GWAS) of total nicotine equivalents: A composite biomarker of nicotine uptake [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 232.

Atopic allergic conditions and colorectal cancer risk in the Multiethnic Cohort Study

Studies have provided evidence of an inverse association between atopic allergic conditions (AACs) and invasive colorectal cancer (CRC) incidence and mortality in predominantly white populations. We examined the association between AACs (asthma, hay fever, or allergy) and CRC among white, African-American, Native Hawaiian, Japanese-American, and Latino men and women in the Multiethnic Cohort Study within Hawaii and Los Angeles, California. The prospective analysis included 4,834 incident CRC cases and 1,363 CRC-related deaths ascertained between 1993 and 2010. We examined associations by ethnicity, location, stage, and potential effect modification by CRC risk factors. AACs were associated with a reduced risk of CRC incidence among both men and women (relative risk (RR) = 0.86, 95% confidence interval (CI): 0.80, 0.92). The reduction in risk was noted in all populations except Latinos and was significant in whites (RR = 0.85, 95% CI: 0.73, 0.98), African Americans (RR = 0.81, 95% CI: 0.70, 0.95), Native Hawaiians (RR = 0.72, 95% CI: 0.54, 0.96), and Japanese Americans (RR = 0.87, 95% CI: 0.78, 0.98). Individuals with AACs also had a 20% reduction in CRC-related mortality (P = 0.001). These findings provide evidence for the potential protective role of the reactive immune system in colorectal cancer.

Pleiotropic and sex-specific effects of cancer GWAS SNPs on melanoma risk in the population architecture using genomics and epidemiology (PAGE) study

Background

Several regions of the genome show pleiotropic associations with multiple cancers. We sought to evaluate whether 181 single-nucleotide polymorphisms previously associated with various cancers in genome-wide association studies were also associated with melanoma risk.

Methods

We evaluated 2,131 melanoma cases and 20,353 controls from three studies in the Population Architecture using Genomics and Epidemiology (PAGE) study (EAGLE-BioVU, MEC, WHI) and two collaborating studies (HPFS, NHS). Overall and sex-stratified analyses were performed across studies.

Results

We observed statistically significant associations with melanoma for two lung cancer SNPs in the TERT-CLPTM1L locus (Bonferroni-corrected p<2.8x10^-4), replicating known pleiotropic effects at this locus. In sex-stratified analyses, we also observed a potential male-specific association between prostate cancer risk variant rs12418451 and melanoma risk (OR=1.22, p=8.0x10^-4). No other variants in our study were associated with melanoma after multiple comparisons adjustment (p>2.8e^-4).

Conclusions

We provide confirmatory evidence of pleiotropic associations with melanoma for two SNPs previously associated with lung cancer, and provide suggestive evidence for a male-specific association with melanoma for prostate cancer variant rs12418451. This SNP is located near TPCN2, an ion transport gene containing SNPs which have been previously associated with hair pigmentation but not melanoma risk. Previous evidence provides biological plausibility for this association, and suggests a complex interplay between ion transport, pigmentation, and melanoma risk that may vary by sex. If confirmed, these pleiotropic relationships may help elucidate shared molecular pathways between cancers and related phenotypes.

Abstract 5064: Pleiotropy analysis identifies a novel prostate cancer variant at 6p21.33: The PAGE, PRACTICAL, and BPC3 Consortia

Background: Genome-wide association studies have identified hundreds of susceptibility loci for various cancer sites including prostate cancer. Several of the risk loci have demonstrated pleiotropic effects with multiple cancers, suggesting shared biological pathways in carcinogenesis. In the present study, we systematically investigated the effects of other cancer-associated variants on prostate cancer risk.

Methods: We examined 196 genetic risk variants identified for 18 cancer and cancer-related traits in a total of 28,135 prostate cancer cases and 37,218 controls. This large meta-analysis of multiethnic samples was assembled from three consortia: Population Architecture using Genetics and Epidemiology (PAGE), Prostate Cancer Association Group to Investigate Cancer Associated Alterations in the Genome (PRACTICAL) and Breast and Prostate Cancer Cohort Consortium (BPC3). Study- and ethnic-specific logistic regressions results were combined through fixed-effect meta-analysis to evaluate the association between each variant and prostate cancer risk, applying a Bonferroni-corrected significance threshold of 2.6×10-4. We also assessed the cumulative effect of other cancer risk variants on prostate cancer susceptibility via risk score analysis.

Results: Three variants, RTEL rs6010620, TERT rs2853676 and HLA rs6457327, demonstrated statistically significant associations with prostate cancer risk after correcting for multiple comparisons. Originally reported as a follicular lymphoma risk variant, rs6457327 was associated with prostate cancer at the genome-wide significant level (meta-analysis OR=0.93, 95% CI: 0.91-0.96; p=4.5×10-8). The cumulative genetic risk score for risk variants of other cancers demonstrated a significant effect on prostate cancer risk (p=0.021).

Conclusions: This systematic pleiotropy analysis identified HLA as a novel susceptibility locus for prostate cancer in a large multiethnic population. The genetic variant with pleiotropic effects on both follicular lymphoma and prostate cancer provides evidence for shared etiologic mechanisms between prostate cancer and other cancer sites.

Citation Format: Ying Han, Shelly-Ann Love, William S. Bush, Daniele Campa, Anne M. Butler, Logan Dumitrescu, Konstantinos Tsilidis, Iona Cheng, Lynne R. Wilkens, Jay H. Fowke, Jose Luis Ambite, Steve Buyske, S. Lani Park, The PRACTICAL Consortium, The BPC3 Consortium, Christopher A. Haiman, Loic Le Marchand, Lucia A. Hindorff, Federico Canzian, Fredrick R. Schumacher. Pleiotropy analysis identifies a novel prostate cancer variant at 6p21.33: The PAGE, PRACTICAL, and BPC3 Consortia. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 5064. doi:10.1158/1538-7445.AM2014-5064

Association of cancer susceptibility variants with risk of multiple primary cancers: The population architecture using genomics and epidemiology study

BACKGROUND

Multiple primary cancers account for approximately 16% of all incident cancers in the United States. Although genome-wide association studies (GWAS) have identified many common genetic variants associated with various cancer sites, no study has examined the association of these genetic variants with risk of multiple primary cancers (MPC).

METHODS

As part of the National Human Genome Research Institute (NHGRI) Population Architecture using Genomics and Epidemiology (PAGE) study, we used data from the Multiethnic Cohort (MEC) and Women's Health Initiative (WHI). Incident MPC (IMPC) cases (n = 1,385) were defined as participants diagnosed with more than one incident cancer after cohort entry. Participants diagnosed with only one incident cancer after cohort entry with follow-up equal to or longer than IMPC cases served as controls (single-index cancer controls; n = 9,626). Fixed-effects meta-analyses of unconditional logistic regression analyses were used to evaluate the associations between 188 cancer risk variants and IMPC risk. To account for multiple comparisons, we used the false-positive report probability (FPRP) to determine statistical significance.

RESULTS

A nicotine dependence-associated and lung cancer variant, CHRNA3 rs578776 [OR, 1.16; 95% confidence interval (CI), 1.05-1.26; P = 0.004], and two breast cancer variants, EMBP1 rs11249433 and TOX3 rs3803662 (OR, 1.16; 95% CI, 1.04-1.28; P = 0.005 and OR, 1.13; 95% CI, 1.03-1.23; P = 0.006), were significantly associated with risk of IMPC. The associations for rs578776 and rs11249433 remained (P < 0.05) after removing subjects who had lung or breast cancers, respectively (P ≤ 0.046). These associations did not show significant heterogeneity by smoking status (Pheterogeneity ≥ 0.53).

CONCLUSIONS

Our study has identified rs578776 and rs11249433 as risk variants for IMPC.

IMPACT

These findings may help to identify genetic regions associated with IMPC risk.

Cross-cancer pleiotropic analysis of endometrial cancer: PAGE and E2C2 consortia

Genome-wide association studies (GWAS) have identified a large number of cancer-associated single nucleotide polymorphisms (SNPs), several of which have been associated with multiple cancer sites suggesting pleiotropic effects and shared biological mechanisms across some cancers. We hypothesized that SNPs associated with other cancers may be additionally associated with endometrial cancer. We examined 213 SNPs previously associated with 14 other cancers for their associations with endometrial cancer in 3758 endometrial cancer cases and 5966 controls of European ancestry from two consortia: Population Architecture Using Genomics and Epidemiology and the Epidemiology of Endometrial Cancer Consortium. Study-specific logistic regression estimates adjusted for age, body mass index and the most significant principal components of genetic ancestry were combined using fixed-effect meta-analysis to evaluate the association between each SNP and endometrial cancer risk. A Bonferroni-corrected P value of 2.35×10(-4) was used to determine statistical significance of the associations. SNP rs7679673, ~6.3kb upstream of TET2 and previously reported to be associated with prostate cancer risk, was associated with endometrial cancer risk in the direction opposite to that for prostate cancer [meta-analysis odds ratio = 0.87 (per copy of the C allele), 95% confidence interval = 0.81, 0.93; P = 7.37×10(-5)] with no evidence of heterogeneity across studies (P heterogeneity = 0.66). This pleiotropic analysis is the first to suggest TET2 as a susceptibility locus for endometrial cancer.

Pleiotropic associations of risk variants identified for other cancers with lung cancer risk: the PAGE and TRICL consortia

BACKGROUND

Genome-wide association studies have identified hundreds of genetic variants associated with specific cancers. A few of these risk regions have been associated with more than one cancer site; however, a systematic evaluation of the associations between risk variants for other cancers and lung cancer risk has yet to be performed.

METHODS

We included 18023 patients with lung cancer and 60543 control subjects from two consortia, Population Architecture using Genomics and Epidemiology (PAGE) and Transdisciplinary Research in Cancer of the Lung (TRICL). We examined 165 single-nucleotide polymorphisms (SNPs) that were previously associated with at least one of 16 non-lung cancer sites. Study-specific logistic regression results underwent meta-analysis, and associations were also examined by race/ethnicity, histological cell type, sex, and smoking status. A Bonferroni-corrected P value of 2.5×10(-5) was used to assign statistical significance.

RESULTS

The breast cancer SNP LSP1 rs3817198 was associated with an increased risk of lung cancer (odds ratio [OR] = 1.10; 95% confidence interval [CI] = 1.05 to 1.14; P = 2.8×10(-6)). This association was strongest for women with adenocarcinoma (P = 1.2×10(-4)) and not statistically significant in men (P = .14) with this cell type (P het by sex = .10). Two glioma risk variants, TERT rs2853676 and CDKN2BAS1 rs4977756, which are located in regions previously associated with lung cancer, were associated with increased risk of adenocarcinoma (OR = 1.16; 95% CI = 1.10 to 1.22; P = 1.1×10(-8)) and squamous cell carcinoma (OR = 1.13; CI = 1.07 to 1.19; P = 2.5×10(-5)), respectively.

CONCLUSIONS

Our findings demonstrate a novel pleiotropic association between the breast cancer LSP1 risk region marked by variant rs3817198 and lung cancer risk.

Effect of DA-9701, a novel prokinetic agent, on stress-induced delayed gastric emptying and hormonal changes in rats

BACKGROUND

DA-9701 is a novel prokinetic agent formulated with Pharbitis Semen and Corydalis Tuber. This study aimed to evaluate the effect of DA-9701 on stress-induced delay in gastric emptying and changes in plasma adrenocorticotropic hormone and ghrelin levels in rats.

METHODS

Changes in gastric emptying in response to different durations of stress were evaluated. Gastric emptying was compared between the following groups: (i) nonstressed vehicle- or DA-9701-treated group, (ii) nonstressed vehicle- or mosapride-treated group, (iii) 2-h stressed vehicle- or DA-9701-treated group, and (iv) 2-h stressed vehicle- or mosapride-treated group. Water immersion restraint stress was used as the stressor. DA-9701 or mosapride at 3 mg kg(-1) was administered to the rats after subjecting them to 2-h stress, and then gastric emptying was measured using the phenol red method.

KEY RESULTS

Gastric emptying was significantly delayed in the 2-h stressed group compared with the nonstressed group. Mosapride administration resulted in significant recovery from the stress-induced delay in gastric emptying. Gastric emptying in the rats that underwent 2-h stress followed by DA-9701 administration was not significantly different from that in the nonstressed group. The plasma adrenocorticotropic hormone and active ghrelin levels in the 2-h stressed group were significantly higher than those in the nonstressed group. These increases were significantly inhibited by DA-9701.

CONCLUSIONS & INFERENCES

The administration of DA-9701 improved delayed gastric emptying and inhibited the hormonal changes induced by stress, suggesting that DA-9701 can be used as a gastroprokinetic agent for the treatment of delayed gastric emptying, particularly that associated with stress.

Phase I/II Study of Continuous-Infusion Troxacitabine in Refractory Acute Myeloid Leukemia

Purpose

Troxacitabine is a non-natural nucleoside analog with unique structural and metabolic features. Bolus intravenous (IV) troxacitabine regimens have shown significant activity in patients with refractory acute myeloid leukemia (AML) and preclinical data suggest that administration via continuous infusion may result in enhanced antitumor activity.

Patients and Methods

Patients with refractory AML initially received troxacitabine 10.1 mg/m2 by continuous IV infusion (CIVI) for 48 hours. Infusion duration and daily dose were increased in subsequent patient cohorts.

Results

Forty-eight patients, median age 58 years (range, 21 to 81 years), were treated. Dose-limiting toxicities were mucositis and hand-foot syndrome, and 12.0 mg/m2/d for 5 days was established as the maximum-tolerated dose. Seven patients (15%) achieved complete remission (CR) or CR with incomplete platelet recovery (CRp), with a median survival among responders of 12 months. Steady-state concentrations of troxacitabine were found to be linearly and inversely proportionally related to calculated creatinine clearance at doses of 10.1 and 12.0 mg/m2/d. All patients responding to troxacitabine had steady-state serum drug concentration of more than approximately 80 ng/mL. In 27 patients achieving target troxacitabine plasma concentrations (ie, approximately 80 ng/mL) the CR + CRp rate was 26%.

Conclusion

Troxacitabine administered as a CIVI allows a significant increase in dose-intensity in comparison to IV bolus regimens, has antileukemic activity, and warrants additional investigation in patients with refractory AML. The recommended phase II study dose is 12.0 mg/m2 daily CIVI for 5 days.

Bowenoid epidermotropic metastatic squamous cell carcinoma

Epidermotropic metastatic squamous cell carcinoma produced full-thickness cellular atypia of bowenoid carcinoma in situ or vulvar intraepithelial neoplasia, grade 3 (VIN 3), in a 73-year-old woman who had past history of uterine cervical carcinoma. The presence of intravascular tumor cell nests and areas showing smooth continuity of the malignant squamous cell nodules with the adjoining benign epidermis supported the possibility of the epidermotropic metastasis. To our knowledge, metastatic epidermotropic squamous carcinoma clinicopathologically simulating primary Bowen's disease has not been reported.

Purification and properties of Lactobacillus plantarum inducible malic enzyme

Inducible malic enzyme (l-malate:NAD oxidoreductase [decarboxylating], EC 1.1.1.39) was isolated from Lactobacillus plantarum and purified about 100-fold with 27% yield of the original activity. Kinetic studies with the purified malic enzyme yielded the following results: pH optimum, 7.6 to 8.0; K(m) for l-malate, 0.38 mM; K(m) for NAD, 0.072 mM; and K(m) for MnCl(2), 0.048 mM. It was shown that this enzyme was inhibited by high concentrations of substrate and nicotinamide adenine dinucleotide (NAD), indicating it may be regulated by substrate or NAD. Molecular weight of 130,000 +/- 10,000 was determined by Sephadex gel filtration and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The isoelectric point, determined by isoelectrofocusing, was 4.3 at 7 C. Isoelectrofocusing also resolved three active peaks which focused at pH 4.19, 4.31, and 4.40.