Divergence in Cigarette Discontinuation Rates by Use of Electronic Nicotine Delivery Systems (ENDS): Longitudinal Findings From the United States PATH Study Waves 1-6

INTRODUCTION

We compare real-world trends in population-level cigarette discontinuation rates among adults (ages ≥21) who smoked cigarettes, by electronic nicotine delivery systems (ENDS) use.

AIMS AND METHODS

U.S nationally representative data from adults in the Population Assessment of Tobacco and Health (PATH) Study (2013/14-2021, Waves 1-6) who smoked cigarettes in the past 30 days (P30D) were analyzed (n = 13 640). The exposure was P30D ENDS use. The outcome was P30D cigarette discontinuation at biennial follow-up. Weighted trend analyses were conducted to test for differences in cigarette discontinuation trends by ENDS use.

RESULTS

Between 2013/14 and 2015/16, cigarette discontinuation rates were both 16% for those who used ENDS and for those who did not; between 2018/19 and 2021, rates were ~30% for those who used ENDS and ~20% for those who did not; the time by ENDS use interaction was significant.

CONCLUSIONS

The relationship between adults' ENDS use and cigarette discontinuation in the context of an expanded ENDS marketplace, new tobacco regulatory actions, and COVID-19 differs from the relationship in earlier years.

IMPLICATIONS

It is important for public health decisions to be informed by research based on the contemporary ENDS marketplace and circumstances.

Cigar Cessation Prevalence and Trends by Demographic Characteristics Among US Adults, TUS-CPS, 2010-2019

INTRODUCTION

Disproportionate rates of cigar smoking across demographic groups can contribute to tobacco-related health disparities in the United States. We assessed overall and demographic-specific cigar cessation rates from 2010 to 2019.

AIMS AND METHODS

To characterize cessation prevalence among selected demographic groups over time, we analyzed data from the 2010-2011, 2014-2015, and 2018-2019 Tobacco Use Supplement to the Current Population Survey (TUS-CPS). Individuals who reported either (1) current cigar smoking for at least 2 years or (2) quitting cigar smoking within the past 12 months were included in the study (n = 5262 in 2010-2011; n = 4741 in 2014-2015; n = 3741 in 2018-2019). Among this group, individuals who reported not smoking a cigar within the past 6 months were considered cigar quitters. Chi-square tests were used to test differences in cessation prevalence between the two survey waves within demographic groups as well as between different groups within survey waves.

RESULTS

The prevalence of cigar cessation decreased from 2010-2011 to 2018-2019 for non-Hispanic (NH) White individuals, Hispanic individuals, and both males and females. (p < .05 for all groups). NH White individuals had significantly higher cessation prevalence than individuals who identified as NH Black (33.8% vs. 25.0%, respectively, in 2010-2011; 33.4% vs. 20.4% in 2014-2015; 31.1% vs. 22.3% in 2018-2019; p < .05 for all differences).

CONCLUSIONS

Overall cigar cessation prevalence significantly decreased from 2010-2011 to 2018-2019. Findings from the study could provide an opportunity to implement strategies that promote cessation strategies targeting certain subpopulations.

IMPLICATIONS

Cigar cessation patterns are starkly different across different demographic groups, which leads to a disproportionate burden of health-related effects of continued use of these products. These results can inform policy actions around cigar cessation efforts. Future research to close this disparity should be focused on populations that have lower cessation prevalence.

Use patterns of flavored non-cigarette tobacco products among US adults, 2010-2019

OBJECTIVE

Flavored non-cigarette tobacco product (NCTP) use is common among US adult tobacco users. To update the estimates of use patterns of flavored NCTPs, this study assessed current NCTP use among adults by flavor use and flavor categories from 2010 to 2019.

METHODS

We analyzed data from the 2010-2019 Tobacco Use Supplement to the Current Population Survey to estimate the weighted proportion of adult NCTP users by flavor use across survey waves. Flavor use was defined as past 30-day use of any menthol/mint or fruit/other flavors. We used the 2018-2019 data to examine the differences in demographic characteristics and tobacco use patterns among users of menthol/mint or fruit/other flavors compared to exclusive users of tobacco flavor, by product type.

RESULTS

Compared to 2014-2015, electronic nicotine delivery system (ENDS) users were more likely (79.0% vs. 66.6%, p < 0.001) to report flavor use in 2018-2019, whereas cigar (26.9% vs. 31.2%, p = 0.030) and pipe (56.3% vs. 65.5%, p = 0.015) smokers were less likely to report flavor use in 2018-2019. In 2018-2019, the most prevalent flavor categories were exclusive use of tobacco flavor among cigar (73.1%) and smokeless tobacco (48.3%) users, and use of fruit/other flavors among ENDS (64.9%) and pipe (48.4%) users. Flavored users were more likely to be young adults aged 18-24 years (cigars, ENDS, smokeless tobacco) and Non-Hispanic Black or Hispanic persons (cigars, ENDS, pipes) compared to tobacco-flavored users.

CONCLUSIONS

Flavored product use increased among adult ENDS users but decreased among cigar and pipe smokers. These findings could inform tobacco regulatory efforts concerning flavored NCTPs.

Smoking cessation prevalence by menthol cigarette use and select demographics among adults in the United States, TUS-CPS, 2003-2019

People who smoke menthol cigarettes, particularly those who are non-Hispanic Black/African American, are less likely to achieve successful smoking cessation compared with people who smoke non-menthol cigarettes. This study examined the 2003-2019 Tobacco Use Supplement to the Current Population Survey (TUS-CPS) harmonized data to estimate cross-sectional trends in cigarette smoking cessation among U.S. adults, stratified by menthol cigarette use, race/ethnicity, sex, and age. The analytic sample included respondents who smoked for ≥ 2 years (current users and former users who reported quitting during the past year). We tested cessation trends using orthogonal polynomial contrasts for overall, menthol, and non-menthol smoking cessation prevalence and stratified by race/ethnicity, sex, and age in logistic regression models. We also analyzed the 2018-2019 non-harmonized TUS-CPS data among recent quitters to examine differences in characteristics (e.g., demographic characteristics, smoking frequency, use of smoking cessation aids, switching to other tobacco products) by menthol cigarette use. We observed significant linear changes in prevalence trends for overall cigarette smoking cessation, menthol smoking cessation, and non-menthol smoking cessation (p < 0.0001 for all linear trends), and changes in menthol cessation among non-Hispanic White and non-Hispanic Other race/ethnicity categories during 2003-2019. In the 2018-2019 wave, we observed differences in menthol status for sex, race/ethnicity, age, and educational attainment. We did not observe differences for other characteristics. We observed changes in overall cigarette smoking cessation, menthol, and non-menthol smoking cessation prevalence during the study period; however, gains in cigarette smoking cessation were not experienced among non-Hispanic Black/African American adults who smoke.

Characteristics and Patterns of Cigarette Smoking and Vaping By Past-Year Smokers Who Reported Using Electronic Nicotine Delivery System to Help Quit Smoking in the Past Year: Findings From the 2018-2019 Tobacco Use Supplement to the Current Population Survey

INTRODUCTION

Cigarette smoking has declined, while electronic nicotine delivery system (ENDS) use has increased in the United States. Understanding the role of ENDS in adult smoking quit attempts and cessation is important for estimating their population health impact.

AIMS AND METHODS

We used data from 2018 to 2019 tobacco use supplement to the current population survey to examine demographic characteristics and ENDS use patterns among adult ENDS users who reported quitting smoking in the past year by trying to switch to ENDS ("switchers") and smokers who did or did not make a quit attempt in the past year. χ2 tests of proportions and t-tests were used to compare characteristics between groups.

RESULTS

In 2018-2019, about three-quarters of switchers reported daily use of ENDS compared to only one-third of dual users with a recent quit attempt by trying to switch to ENDS. Compared to dual users who made a quit attempt by trying to switch to ENDS, switchers were more likely to use menthol/mint-flavored ENDS exclusively (5.6% vs. 13.1%; p = .004) but less likely to use tobacco-flavored ENDS exclusively (21.2% vs. 13.7%; p = .01).

CONCLUSIONS

ENDS users who quit smoking in the past year and reported trying to quit by switching to ENDS were more likely to use menthol/mint flavors exclusively and use ENDS daily compared to dual users who made a quit attempt by trying to switch to ENDS. Longer-term prospective data may better clarify the role of ENDS in smoking quit attempts and cessation.

IMPLICATIONS

This study provides information on patterns of ENDS use in former smokers and current smokers who tried to quit smoking by switching to ENDS in a national sample of U.S. adults. These results can inform policy actions concerning ENDS products.

Menthol Cigarette Smoking Trends Among United States Adults, 2003-2019

BACKGROUND

Smoking is declining, except among current menthol cigarette smokers. This study examines menthol cigarette smoking in the United States.

METHODS

Cross-sectional data from 35,279 self-respondent current adult smokers who selected menthol cigarettes as their usual type, across the 2003, 2006-2007, 2010-2011, 2014-2015, and 2018-2019 waves of the nationally-representative Tobacco Use Supplement to the Current Population Survey, were analyzed in SAS/SUDAAN. Menthol cigarette smoking among current smokers was assessed by sex, age, race/ethnicity, employment, geography, and educational attainment. Linear contrasts were used to assess trends.

RESULTS

Overall cigarette smoking (12.6% in 2018-2019 from 17.3% in 2003) and menthol cigarette smoking (4.0% in 2018-2019 from 4.7% in 2003) in the population decreased in 2018-2019 from 2003 (both p<0.001). Using predicted marginals, adjusted by demographics, menthol smoking among current smokers increased to 33.8% in 2018-2019 from 27.9% in 2003 (p<0.001). Among current smoking adults, increases in menthol smoking were observed among non-Hispanic Black persons (76.8% in 2018-2019 from 73.0% in 2003), young adults (37.7% in 2018-2019 from 31.7% in 2003), and females (39.6% in 2018-2019 from 32.1% in 2003).

CONCLUSIONS

Smoking and menthol smoking in the population has decreased, yet menthol smoking among current smokers increased from 2003 to 2018-2019. Young adult, female, and non-Hispanic Black current smokers were more likely to use menthol cigarettes than their counterparts; these differences have persisted.

IMPACT

Increased menthol smoking among current smokers, notably young adults, women, and non-Hispanic Black individuals, highlights the need for targeted tobacco control interventions for these health disparity populations.

Smokeless Tobacco Use and Prevalence of Cardiovascular Disease Among Males in the Population Assessment of Tobacco and Health (PATH) Study, Waves 1–4

•

Oral smokeless tobacco (SLT) products are non-combusted forms of tobacco that can be dependence producing.

•

SLT use may pose health risks to users such as cardiovascular disease (CVD) through various pathways including influencing hemodynamics, endothelial dysfunction, inflammation, insulin resistance, hyperlipidemia, and arrhythmogenesis.

•

Past studies have suggested a small, elevated risk of CVD among SLT users compared to never tobacco users.

•

This study advances the literature by exploring how the duration of regular SLT use relates to CVD prevalence.

•

In this study of ≥ 40-year-old men only, we did not find a consistent dose–response trend for years of SLT use and prevalence of CVD.

The purpose of this period prevalence study is to compare the prevalence of cardiovascular disease (CVD) in current/former established smokeless tobacco (SLT) users (ever SLT users who have used the product fairly regularly) to those who were: 1) never established cigarette smokers and SLT users, and 2) current/former established exclusive cigarette smokers (have smoked at least a 100 or more cigarettes in lifetime) only, adjusting for known risk factors for CVD. Analyses included 4,703 men ≥ 40 years of age who participated in the Population Assessment of Tobacco and Health (PATH) Study, Waves: 1–4, conducted between 2013 and 2017. Current users were those using SLT products daily or on some days, whereas former users had not used SLT and/or cigarettes in the past 12 months. CVD prevalence was defined as a self-reported diagnosis of congestive heart failure, stroke, or myocardial infarction. Among current/former established SLT users, years of use defined exposure history, while pack-years defined exposure history for smokers. Adjusted odds ratios (AOR) and 95% confidence intervals (CI) were reported with trend tests to examine dose–response associations. Current/former established exclusive SLT users were not significantly more likely to have had any CVD compared to never established cigarette and SLT users (OR = 1.7 [0.8–3.7]), or current/former established exclusive cigarette smokers (OR = 0.9 [0.5–1.8]). Current/former established exclusive cigarette smokers were more likely to have had any CVD compared to those who were never established cigarette and SLT users (OR = 1.6 [1.1–2.3]).

Biomarkers of Inflammation and Oxidative Stress among Adult Former Smoker, Current E-Cigarette Users-Results from Wave 1 PATH Study

BACKGROUND

Former smokers who currently use e-cigarettes have lower concentrations of biomarkers of tobacco toxicant exposure than current smokers. It is unclear whether tobacco toxicant exposure reductions may lead to health risk reductions.

METHODS

We compared inflammatory biomarkers (high-sensitivity C-reactive protein, IL6, fibrinogen, soluble intercellular adhesion molecule-1) and an oxidative stress marker (F2-isoprostane) among 3,712 adult participants in Wave 1 (2013-2014) of the Population Assessment of Tobacco and Health Study by tobacco user groups: dual users of cigarettes and e-cigarettes; former smokers who currently use e-cigarettes-only; current cigarette-only smokers; former smokers who do not currently use any tobacco; and never tobacco users. We calculated geometric means (GM) and estimated adjusted GM ratios (GMR).

RESULTS

Dual users experienced greater concentration of F2-isoprostane than current cigarette-only smokers [GMR 1.09 (95% confidence interval, CI, 1.03-1.15)]. Biomarkers were similar between former smokers who currently use e-cigarettes and both former smokers who do not use any tobacco and never tobacco users, but among these groups most biomarkers were lower than those of current cigarette-only smokers. The concentration of F2-isoprostane decreased by time since smoking cessation among both exclusive e-cigarette users (P _trend = 0.03) and former smokers who do not currently use any tobacco (P _trend = 0.0001).

CONCLUSIONS

Dual users have greater concentration of F2-isoprostane than smokers. Exclusive e-cigarette users have biomarker concentrations that are similar to those of former smokers who do not currently use tobacco, and lower than those of exclusive cigarette smokers.

IMPACT

This study contributes to an understanding of the health effects of e-cigarettes.

Associations between Biomarkers of Exposure and Lung Cancer Risk among Exclusive Cigarette Smokers in the Golestan Cohort Study

Biomarkers of tobacco exposure are known to be associated with disease risk but previous studies are limited in number and restricted to certain regions. We conducted a nested case-control study examining baseline levels and subsequent lung cancer incidence among current male exclusive cigarette smokers in the Golestan Cohort Study in Iran. We calculated geometric mean biomarker concentrations for 28 matched cases and 52 controls for the correlation of biomarker levels among controls and for adjusted odds' ratios (ORs) for lung cancer incidence by biomarker concentration, accounting for demographic characteristics, smoking quantity and duration, and opium use. Lung cancer cases had higher average levels of most biomarkers including total nicotine equivalents (TNE-2), 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), and 3-hydroxyfluorene (3-FLU). Many biomarkers correlated highly with one another including TNE-2 with NNAL and N-Acetyl-S-(2-cyanoethyl)-L-cysteine (2CYEMA), and N-Acetyl-S-(4-hydroxy-2-buten-1-yl)-L-cysteine (t4HBEMA) with N-Acetyl-S-(3-hydroxypropyl-1-methyl)-L-cysteine (3HMPMA) and N-Acetyl-S-(4-hydroxy-2-methyl-2-buten-1-yl)-L-cysteine (4HMBEMA). Lung cancer risk increased with concentration for several biomarkers, including TNE-2 (OR = 2.22, 95% CI = 1.03, 4.78) and NNN (OR = 2.44, 95% CI = 1.13, 5.27), and estimates were significant after further adjustment for demographic and smoking characteristics for 2CYEMA (OR = 2.17, 95% CI = 1.03, 4.55), N-Acetyl-S-(2-carbamoylethyl)-L-cysteine (2CAEMA) (OR = 2.14, 95% CI = 1.01, 4.55), and N-Acetyl-S-(2-hydroxypropyl)-L-cysteine (2HPMA) (OR = 2.85, 95% CI = 1.04, 7.81). Estimates were not significant with adjustment for opium use. Concentrations of many biomarkers were higher at the baseline for participants who subsequently developed lung cancer than among the matched controls. Odds of lung cancer were higher for several biomarkers including with adjustment for smoking exposure for some but not with adjustment for opium use.

Biomarkers of Potential Harm among Adult Cigarette and Smokeless Tobacco Users in the PATH Study Wave 1 (2013-2014): A Cross-sectional Analysis

BACKGROUND

While smokeless tobacco (ST) causes oral cancer and is associated with cardiovascular diseases, less is known about how its effects differ from other tobacco use. Biomarkers of potential harm (BOPH) can measure short-term health effects such as inflammation and oxidative stress.

METHODS

We compared BOPH concentrations [IL6, high-sensitivity C-reactive protein, fibrinogen, soluble intercellular adhesion molecule-1 (sICAM-1), and F2-isoprostane] across 3,460 adults in wave 1 of the Population Assessment of Tobacco and Health study (2013-2014) by tobacco use groups: primary ST users (current exclusive ST use among never smokers), secondary ST users (current exclusive ST use among former smokers), exclusive cigarette smokers, dual users of ST and cigarettes, former smokers, and never tobacco users. We estimated geometric mean ratios using never tobacco users, cigarette smokers, and former smokers as referents, adjusting for demographic and health conditions, creatinine (for F2-isoprostane), and pack-years in smoker referent models.

RESULTS

BOPH levels among primary ST users were similar to both never tobacco users and former smokers. Most BOPH levels were lower among ST users compared with current smokers. Compared with never tobacco users, dual users had significantly higher sICAM-1, IL6, and F2-isoprostane. However, compared with smokers, dual users had similar biomarker levels. Former smokers and secondary ST users had similar levels of all five biomarkers.

CONCLUSIONS

ST users have lower levels of inflammatory and oxidative stress biomarkers than smokers.

IMPACT

ST use alone and in combination with smoking may result in different levels of inflammatory and oxidative stress levels.

High tumor mutation burden fails to predict immune checkpoint blockade response across all cancer types

BACKGROUND

High tumor mutation burden (TMB-H) has been proposed as a predictive biomarker for response to immune checkpoint blockade (ICB), largely due to the potential for tumor mutations to generate immunogenic neoantigens. Despite recent pan-cancer approval of ICB treatment for any TMB-H tumor, as assessed by the targeted FoundationOne CDx assay in nine tumor types, the utility of this biomarker has not been fully demonstrated across all cancers.

PATIENTS AND METHODS

Data from over 10 000 patient tumors included in The Cancer Genome Atlas were used to compare approaches to determine TMB and identify the correlation between predicted neoantigen load and CD8 T cells. Association of TMB with ICB treatment outcomes was analyzed by both objective response rates (ORRs, N = 1551) and overall survival (OS, N = 1936).

RESULTS

In cancer types where CD8 T-cell levels positively correlated with neoantigen load, such as melanoma, lung, and bladder cancers, TMB-H tumors exhibited a 39.8% ORR to ICB [95% confidence interval (CI) 34.9-44.8], which was significantly higher than that observed in low TMB (TMB-L) tumors [odds ratio (OR) = 4.1, 95% CI 2.9-5.8, P < 2 × 10^-16]. In cancer types that showed no relationship between CD8 T-cell levels and neoantigen load, such as breast cancer, prostate cancer, and glioma, TMB-H tumors failed to achieve a 20% ORR (ORR = 15.3%, 95% CI 9.2-23.4, P = 0.95), and exhibited a significantly lower ORR relative to TMB-L tumors (OR = 0.46, 95% CI 0.24-0.88, P = 0.02). Bulk ORRs were not significantly different between the two categories of tumors (P = 0.10) for patient cohorts assessed. Equivalent results were obtained by analyzing OS and by treating TMB as a continuous variable.

CONCLUSIONS

Our analysis failed to support application of TMB-H as a biomarker for treatment with ICB in all solid cancer types. Further tumor type-specific studies are warranted.

Prediction of COPD risk accounting for time-varying smoking exposures

RATIONALE

Chronic Obstructive Pulmonary Disease (COPD) is the fourth leading cause of death in the United States. Studies have primarily assessed the relationship between smoking on COPD risk focusing on summary measures, like smoking status.

OBJECTIVE

Develop a COPD risk prediction model incorporating individual time-varying smoking exposures.

METHODS

The Nurses' Health Study (N = 86,711) and the Health Professionals Follow-up Study (N = 39,817) data was used to develop a COPD risk prediction model. Data was randomly split in 50-50 samples for model building and validation. Cox regression with time-varying covariates was used to assess the association between smoking duration, intensity and year-since-quit and self-reported COPD diagnosis incidence. We evaluated the model calibration as well as discriminatory accuracy via the Area Under the receiver operating characteristic Curve (AUC). We computed 6-year risk of COPD incidence given various individual smoking scenarios.

RESULTS

Smoking duration, year-since-quit (if former smokers), sex, and interaction of sex and smoking duration are significantly associated with the incidence of diagnosed COPD. The model that incorporated time-varying smoking variables yielded higher AUCs compared to models using only pack-years. The AUCs for the model were 0.80 (95% CI: 0.74-0.86) and 0.73 (95% CI: 0.70-0.77) for males and females, respectively.

CONCLUSIONS

Utilizing detailed smoking pattern information, the model predicts COPD risk with better accuracy than models based on only smoking summary measures. It might serve as a tool for early detection programs by identifying individuals at high-risk for COPD.

Characterization of acrylonitrile exposure in the United States based on urinary n-acetyl-S-(2-cyanoethyl)-L-cysteine (2CYEMA): NHANES 2011-2016

BACKGROUND

Acrylonitrile is a possible human carcinogen that is used in polymers and formed in tobacco smoke. We assessed acrylonitrile exposure in the US population by measuring its urinary metabolites N-acetyl-S-(4-hydroxy-2-methyl-2-buten-1-yl)-L-cysteine (2CYEMA) and N-acetyl-S-(1-cyano-2-hydroxyethyl)-L-cysteine (1CYHEMA) in participants from the 2011-2016 National Health and Nutrition Examination Survey.

OBJECTIVE

To assessed acrylonitrile exposure using population-based biomonitoring data of the US civilian, non-institutionalized population.

METHODS

Laboratory data for 8057 participants were reported for 2CYEMA and 1CYHEMA using ultrahigh-performance liquid chromatography/tandem mass spectrometry. Exclusive tobacco smokers were distinguished from non-users using a combination of self-reporting and serum cotinine data. We used multiple linear regression models to fit 2CYEMA concentrations with sex, age, race/Hispanic origin, and tobacco user group as predictor variables.

RESULTS

The median 2CYEMA level was higher for exclusive cigarette smokers (145 µg/g creatinine) than for non-users (1.38 µg/g creatinine). Compared to unexposed individuals (serum cotinine ≤0.015 ng/ml) and controlling for confounders, presumptive second-hand tobacco smoke exposure (serum cotinine >0.015 to ≤10 ng/ml and 0 cigarettes per day, CPD) was significantly associated with 36% higher 2CYEMA levels (p < 0.0001). Smoking 1-10 CPD was significantly associated with 6720% higher 2CYEMA levels (p < 0.0001).

SIGNIFICANCE

We show that tobacco smoke is an important source of acrylonitrile exposure in the US population and provide important biomonitoring data on acrylonitrile exposure.

Abstract SP012: Convergent evolution of resistance pathways during early stage breast cancer treatment with combination cell cycle (CDK) and endocrine signaling inhibitors

Combining cyclin-dependent kinase (CDK) inhibitors with endocrine therapy improves outcomes for metastatic estrogen receptor positive (ER+), HER2 negative, breast cancer patients. However, the value of this combination in potentially curable earlier stage patients is not clear. Using single cell transcriptomic profiling, we examined the evolutionary trajectories of early stage breast cancer tumors using serial tumor biopsies from a clinical trial of preoperative endocrine therapy alone (letrozole) or in combination with the cell cycle inhibitor ribociclib. Applying hierarchical regression and Gaussian process mathematical modelling, we classified each tumor by whether it shrinks or persists with therapy and determined cancer phenotypes related to evolution of resistance and cell cycle transcriptional rewiring. We found that all patients’ tumors undergo subclonal evolution during therapy, irrespective of the clinical response. However, tumors subjected to endocrine therapy alone showed reduced diversity over time, those facing combination therapy exhibited increased diversity. Despite different diversity, single nuclei RNA sequencing uncovered common phenotypic changes in tumor cells that persist following treatment. In these tumors, accelerated loss of estrogen signaling is convergent with up-regulation of the JNK pathway, while persistent tumors that maintain estrogen signaling during therapy show potentiation of CDK4/6 activation consistent with ERBB4 and ERK signaling up-regulation. Cell cycle reconstruction identified that these tumors can rebound during combination therapy treatment, indicating stronger selection and promotion of a proliferative state. These results indicate that combination therapy in early stage ER+ breast cancers with ER and CDK inhibition drives rapid evolution of resistance via a shift from estrogen signaling to alternative growth factor receptor mediated proliferation and JNK signaling activation, concordant with a bypass in the G1 checkpoint.

Citation Format: JI Griffiths, J Chen, PA Cosgrove, A O'Dea, P Sharma, CX Ma, M Trivedi, K Kalinsky, KB Wisinski, R O'Reagan, I Makhoul, LM Spring, A Bardia, FR Adler, AL Cohen, JT Chang, QJ Khan, AH Bild. Convergent evolution of resistance pathways during early stage breast cancer treatment with combination cell cycle (CDK) and endocrine signaling inhibitors [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr SP012.

ENDS Flavor Preference by Menthol Cigarette Smoking Status among US Adults, 2018-2019

E-cigarette flavor preference may differ among smokers using e-cigarettes, but little information is available on preferences by menthol cigarette status. Using nationally representative data for US adults from the 2018-2019 Tobacco Use Supplement to the Current Population Survey, we analyzed e-cigarette flavor preference by menthol cigarette status and e-cigarette device type for dual-cigarette and e-cigarette users and e-cigarette users who had recently quit smoking by trying to switch to e-cigarettes ("switchers"). Approximately half (52.2%) of dual users of menthol cigarettes and e-cigarettes reported using menthol/mint-flavored e-cigarettes as did 41.4% of "switchers" who had smoked menthol cigarettes; exclusive menthol/mint flavor use was 13.1% for dual users and 21.3% for "switchers." A similar proportion (45.1%) of dual users who smoked nonmenthol cigarettes used tobacco-flavored e-cigarettes, but only 26.7% of "switchers" who had smoked nonmenthol cigarettes used tobacco-flavored e-cigarettes. Approximately 60% of dual users and "switchers" used fruit/other flavors, regardless of menthol cigarette use. By device type, 63.9% of dual users of cartridge-based e-cigarettes and menthol cigarettes used menthol/mint-flavored e-cigarettes. Approximately 75% of dual users and 85% of "switchers" who used tank or mod systems used fruit/other flavors. Menthol cigarette smokers may be particularly likely to use menthol/mint e-cigarettes, and a majority of dual users and "switchers" used fruit/other flavors. These results can inform policy measures concerning flavored electronic nicotine delivery system products.

National Estimates of ENDS Liquid Nicotine Exposures, U.S., 2013-2017

INTRODUCTION

Increased use of ENDS in the U.S. is related to acute adverse events from liquid nicotine exposure. This paper provides national estimates of U.S. hospital emergency department visits for exposures from liquid nicotine exposure in individuals aged ≥5 years.

METHODS

In 2018-2019, data from the 2013-2017 National Electronic Injury Surveillance System All Injury Program were used to identify cases of liquid nicotine-related exposures in individuals aged ≥5 years. National estimates of exposures related to liquid nicotine exposure in ENDS for those aged ≥5 years by demographic characteristics, symptoms, diagnoses, and treatment dispositions were calculated.

RESULTS

From 2013 to 2017, an estimated 2,718 cases related to liquid nicotine among those aged ≥5 years were treated in U.S. hospital emergency departments. Most exposures occurred among those who were aged ≥25 years (51.7%), white (74.1%), and male (51.9%). Most case patients were treated and released from the hospitals, and 7.5% were admitted. Poisoning was the most common diagnosis of these exposures (82.7%). The most common symptoms were cardiovascular (29.7%).

CONCLUSIONS

This study provides national estimates of emergency department visits for injury and poisoning cases related to nicotine exposure from ENDS among individuals aged ≥5 years. Although long-term health outcome studies of liquid nicotine exposure are not available, these estimates provide some insight into the acute health effects. Findings from this study may inform education programs aimed at preventing exposures related to ENDS products.

Trends and Associations of Menthol Cigarette Smoking Among US Middle and High School Students-National Youth Tobacco Survey, 2011-2018

INTRODUCTION

Youth cigarette smoking decreased significantly over the last two decades in the United States. This study provides estimates and trends from 2011 to 2018 and factors associated with youth menthol and non-menthol smoking from 2016 to 2018.

METHODS

Using data from the 2011-2018 National Youth Tobacco Surveys, past 30-day (current) menthol and non-menthol cigarette smoking were estimated for all youth (prevalence) and youth smokers (proportions). Trends were examined using Joinpoint regression, calculating the annual percent change (APC). Multivariate logistic regression analyses identified factors associated with menthol smoking.

RESULTS

From 2011 to 2018, menthol cigarette smoking among current youth cigarette smokers significantly decreased from 57.3% to 45.7% (APC: -3.0%), while non-menthol (38.2% to 47.3% [APC: 2.9%]) and unknown menthol status (not sure\missing) (4.5% to 7.0% [APC: 7.1%]) significantly increased. Menthol cigarette smoking among high school, male, female, and non-Hispanic white current cigarette smokers decreased, but remained unchanged among middle school, non-Hispanic black, and Hispanic smokers. Significantly higher proportions of menthol cigarette smokers smoked on ≥20 days, ≥2 cigarettes per day, and ≥100 cigarettes in their lifetime compared to non-menthol smokers. Among current cigarette smokers, non-Hispanic blacks, Hispanics, flavored non-cigarette tobacco users, frequent smokers (≥20 days), those smoking 2-5 cigarettes per day, and those living with someone who uses tobacco had higher odds of menthol cigarette smoking.

CONCLUSIONS

In 2018, nearly half of current youth cigarette smokers smoked menthol cigarettes. While menthol cigarette smoking declined from 2011 to 2018 among all youth and among youth smokers, there was no change in menthol cigarette smoking among non-Hispanic black, Hispanic, and middle school cigarette smokers.

IMPLICATIONS

This study finds that overall cigarette and menthol cigarette smoking declined in youth from 2011 to 2018. However, menthol cigarette smoking among non-Hispanic black, Hispanic, and middle school youth cigarette smokers did not change. Information from this study can help inform efforts to reduce menthol cigarette smoking among US youth, particularly racial/ethnic minority populations.

Changes in Cigarettes per Day and Biomarkers of Exposure Among US Adult Smokers in the Population Assessment of Tobacco and Health Study Waves 1 and 2 (2013-2015)

INTRODUCTION

Some studies have found some reduction in tobacco exposure and tobacco-related disease risk with decreased numbers of cigarettes smoked per day (CPD), but biomarker of exposure estimates by change in CPD are generally unavailable for the US population.

METHODS

We analyzed biomarker of exposure data by smoking status from over 1100 adult exclusive daily cigarette smokers in Wave 1 of the Population Assessment of Tobacco and Health (PATH) Study who were either exclusive daily smokers or had quit tobacco use entirely at Wave 2. Wave 1 smoking categories consisted of "very light" (1-4 CPD), "light" (5-9 CPD), "moderate" (10-19 CPD), and "heavy" (20+ CPD), and Wave 2 categories were "quitters" (stopped smoking entirely), exclusive cigarette "reducers" (CPD decreased ≥ 50%), "maintainers" (CPD within 50%-150% of Wave 1 value), and "increasers" (CPD increased ≥ 50%).

RESULTS

Complete quitters had significantly lower levels of TNE-2, NNAL, NNN, 2-Fluorene, HPMA, CYMA, and MHB3 at Wave 2 for all Wave 1 CPD categories, and decreases were often large. Moderate "reducers" had lower levels of NNAL and 1-Hydroxypyrene at Wave 2, and heavy "reducers" had lower levels of NNAL, 2-Fluorene, and MHB3. Light "increasers" had higher levels of TNE-2, NNAL, 2-Fluorene, CYMA, and cadmium at Wave 2, and heavy "increasers" had higher levels of NNAL and HPMA.

CONCLUSIONS

Smoking "reducers" and "increasers" had changes in some biomarker of tobacco exposure levels, but reductions were much greater and more consistent for complete quitters.

IMPLICATIONS

PATH longitudinal cohort study data show that some exclusive daily cigarette smokers increase or decrease CPD over time. These differences may result in moderate changes in the levels of some biomarkers such as NNAL. Even so, however, reductions in biomarker levels are much greater with complete smoking cessation.

Cigarette Smoking Reduction and Health Risks: A Systematic Review and Meta-analysis

Introduction

Studies have shown the health benefits of cigarette smoking cessation. However, the literature remains unclear about the relationship between smoking reduction and health risks. This comprehensive review and meta-analysis updates previous reviews with the newest estimates.

Aims and Methods

We conducted a systematic review and meta-analysis evaluating the association between smoking reduction and some health risks in observational studies. We defined the following smoking categories: heavy smokers smoked ≥15–20 cigarettes per day (CPD), moderate smokers smoked 10–19 CPD, and light smokers smoked &lt;10 CPD. The relative risks (RRs) and 95% confidence intervals (CIs) were estimated using random-effect models.

Results

We identified 19 studies including four case–control and 15 cohort studies. Compared with continuing heavy smokers, we found decreased lung cancer risk for those who reduced CPD by more than 50% (RR = 0.72, 95% CI: 0.52, 0.91), from heavy to moderate (RR = 0.66, 95% CI: 0.46, 0.85), and from heavy to light (RR = 0.60, 95% CI: 0.49, 0.72). We also found lower risk of cardiovascular disease (CVD) for those who reduced from heavy to light smoking (RR = 0.78, 95% CI: 0.67, 0.89) but not those who reduced by more than 50% and reduced smoking from heavy to moderate. We did not find any significant difference in all-cause mortality, all-cancer risks, and smoking-/tobacco-related cancer risk among those who reduced.

Conclusions

Substantial smoking reduction may decrease lung cancer risk but results on CVD (coronary heart disease and stroke combined) risk were mixed. The relationships between smoking reduction and other endpoints examined were not significant.

Implications

This meta-analysis helps clarify our understanding of various smoking reduction levels on some health risks. While smoking reduction may decrease risks of lung cancer, the relationships between smoking reduction and other endpoints, including all-cause mortality and cardiovascular disease, remain unclear. Although smoking reduction may decrease lung cancer risks, the magnitude of lung cancer risk remain high. Among smokers, complete cessation remains the most effective approach for cancer and CVD prevention.

National Estimates of hospital emergency department visits due to acute injuries associated with hookah smoking, United States, 2011-2019

INTRODUCTION

Hookah (also known as waterpipe) smoking is associated with acute adverse health effects such as vomiting and fainting, symptoms related to carbon monoxide poisoning, and decreased pulmonary function, however, national estimates of hookah-related acute injuries are not currently available in the scientific literature. This study provides national estimates of United States hospital emergency department visits due to hookah-related acute injuries.

METHODS

We analyzed 2011-2019 data from the National Electronic Injury Surveillance System to calculate national estimates of emergency department visits due to hookah-related acute injuries. National Electronic Injury Surveillance System data were gathered from approximately 100 United States hospitals selected as a probability sample of approximately 5000 hospitals with emergency departments. Each case contains information abstracted from all emergency department records involving injuries associated with consumer products. All individuals admitted to emergency departments who sustained hookah-related acute injuries were included in the study.

RESULTS

During 2011-2019, an estimated 1371 (95% confidence interval: 505-2283) United States hospital emergency department visits were related to hookah-related acute injuries. The most common injuries were sustained from dizziness/light-headedness and syncopal episodes (54.8%), followed by burns (41.5%). Young adults aged 18-24 years accounted for 66.8% of hookah-related acute injuries admitted to United States emergency departments.

CONCLUSIONS

This study provides national estimates of hospital emergency department visits due to hookah-related acute injuries. We found that hookah smoking related AIs mostly occurred among young adults. Study findings may inform public health policy and educational intervention efforts to prevent these events and complement other acute injury surveillance systems, such as the National Poison Data System.

Urinary Biomarkers of Exposure to Volatile Organic Compounds from the Population Assessment of Tobacco and Health Study Wave 1 (2013-2014)

Volatile organic compounds (VOCs) are ubiquitous in the environment. In the United States (U.S.), tobacco smoke is the major non-occupational source of exposure to many harmful VOCs. Exposure to VOCs can be assessed by measuring their urinary metabolites (VOCMs). The Population Assessment of Tobacco and Health (PATH) Study is a U.S. national longitudinal study of tobacco use in the adult and youth civilian non-institutionalized population. We measured 20 VOCMs in urine specimens from a subsample of adults in Wave 1 (W1) (2013-2014) to characterize VOC exposures among tobacco product users and non-users. We calculated weighted geometric means (GMs) and percentiles of each VOCM for exclusive combustible product users (smokers), exclusive electronic cigarette (e-cigarette) users, exclusive smokeless product users, and tobacco product never users. We produced linear regression models for six VOCMs with sex, age, race, and tobacco user group as predictor variables. Creatinine-ratioed levels of VOCMs from exposure to acrolein, crotonaldehyde, isoprene, acrylonitrile, and 1,3-butadiene were significantly higher in smokers than in never users. Small differences of VOCM levels among exclusive e-cigarette users and smokeless users were observed when compared to never users. Smokers showed higher VOCM concentrations than e-cigarette, smokeless, and never users. Urinary VOC metabolites are useful biomarkers of exposure to harmful VOCs.

Temporal Changes in Head and Neck Cancer Incidence in Thailand Suggest Changing Oropharyngeal Epidemiology in the Region

PURPOSE

Head and neck cancer is the sixth most common cancer in the world, and the largest burden occurs in developing countries. Although the primary risk factors have been well characterized, little is known about temporal trends in head and neck cancer across Thailand.

METHODS

Head and neck squamous cell carcinoma (HNSCC) occurrences diagnosed between 1990 and 2014 were selected by International Classification of Diseases (10th revision; ICD10) code from the Songkhla, Lampang, Chiang Mai, and Khon Kaen cancer registries and the US SEER program for oral cavity (ICD10 codes 00, 03-06), tongue (ICD10 codes 01-02), pharynx (ICD10 codes 09-10, 12-14), and larynx (ICD10 code 32). The data were analyzed using R and Joinpoint regression software to determine age-standardized incidence rates and trends of annual percent change (APC). Incidence rates were standardized using the Segi (1960) population. Stratified linear regression models were conducted to assess temporal trends in early-onset HNSCC across 20-year age groups.

RESULTS

Although overall HNSCC rates are decreasing across all registries, subsite analyses demonstrate consistent decreases in both larynx and oral cavity cancers but suggest increases in tongue cancers among both sexes in the United States (APC_men, 2.36; APC_women, 0.77) and in pharyngeal cancer in Khon Kaen and US men (APC, 2.1 and 2.23, respectively). Age-stratified APC analyses to assess young-onset (< 60 years old) trends demonstrated increased incidence in tongue cancer in Thailand and the United States as well as in pharyngeal cancers in Khon Kaen men age 40 to 59 years and US men age 50 to 59 years.

CONCLUSION

Although overall trends in HNSCC are decreasing across both Thailand and the United States, there is reason to believe that the etiologic shift to oropharyngeal cancers in the United States may be occurring in Thailand.

e-Cigarette Use Among Youth in the United States, 2019

IMPORTANCE

The prevalence of e-cigarette use among US youth increased from 2011 to 2018. Continued monitoring of the prevalence of e-cigarette and other tobacco product use among youth is important to inform public health policy, planning, and regulatory efforts.

OBJECTIVE

To estimate the prevalence of e-cigarette use among US high school and middle school students in 2019 including frequency of use, brands used, and use of flavored products.

DESIGN, SETTING, AND PARTICIPANTS

Cross-sectional analyses of a school-based nationally representative sample of 19 018 US students in grades 6 to 12 participating in the 2019 National Youth Tobacco Survey. The survey was conducted from February 15, 2019, to May 24, 2019.

MAIN OUTCOMES AND MEASURES

Self-reported current (past 30-day) e-cigarette use estimates among high school and middle school students; frequent use (≥20 days in the past 30 days) and usual e-cigarette brand among current e-cigarette users; and use of flavored e-cigarettes and flavor types among current exclusive e-cigarette users (no use of other tobacco products) by school level and usual brand. Prevalence estimates were weighted to account for the complex sampling design.

RESULTS

The survey included 10 097 high school students (mean [SD] age, 16.1 [3.0] years; 47.5% female) and 8837 middle school students (mean [SD] age, 12.7 [2.8] years; 48.7% female). The response rate was 66.3%. An estimated 27.5% (95% CI, 25.3%-29.7%) of high school students and 10.5% (95% CI, 9.4%-11.8%) of middle school students reported current e-cigarette use. Among current e-cigarette users, an estimated 34.2% (95% CI, 31.2%-37.3%) of high school students and 18.0% (95% CI, 15.2%-21.2%) of middle school students reported frequent use, and an estimated 63.6% (95% CI, 59.3%-67.8%) of high school students and 65.4% (95% CI, 60.6%-69.9%) of middle school students reported exclusive use of e-cigarettes. Among current e-cigarette users, an estimated 59.1% (95% CI, 54.8%-63.2%) of high school students and 54.1% (95% CI, 49.1%-59.0%) of middle school students reported JUUL as their usual e-cigarette brand in the past 30 days; among current e-cigarette users, 13.8% (95% CI, 12.0%-15.9%) of high school students and 16.8% (95% CI, 13.6%-20.7%) of middle school students reported not having a usual e-cigarette brand. Among current exclusive e-cigarette users, an estimated 72.2% (95% CI, 69.1%-75.1%) of high school students and 59.2% (95% CI, 54.8%-63.4%) of middle school students used flavored e-cigarettes, with fruit, menthol or mint, and candy, desserts, or other sweets being the most commonly reported flavors.

CONCLUSIONS AND RELEVANCE

In 2019, the prevalence of self-reported e-cigarette use was high among high school and middle school students, with many current e-cigarette users reporting frequent use and most of the exclusive e-cigarette users reporting use of flavored e-cigarettes.

Electronic nicotine delivery system (ENDS) liquid nicotine exposure in young children presenting to US emergency departments, 2018

Background

Increased use of electronic nicotine delivery systems (ENDS) in the United States (U.S.) has been related to acute adverse events from liquid nicotine exposure. Previous studies have reported on these events through 2017.

Findings

We used 2018 National Emergency Injury Surveillance System data to generate national estimates with 95% confidence intervals (CIs) of ENDS liquid nicotine-related poisonings among children under age 5 treated in U.S. hospital emergency departments (EDs). In 2018, an estimated 885 (95% CI: 397–1374) poisoning cases related to liquid nicotine among children under 5 were treated in U.S. EDs, which was a non-statistically signficant increase from 2017 (411 poisoning cases, 95% CI: 84–738). The most common route of exposure was through ingestion (99.4%). The majority of cases were treated and released from the hospital (90.0%), 8.9% of the cases left the hospital without being seen, and 1.1% of the cases were treated and admitted to the hospital.

Conclusions

This study provides updated national estimates of poisoning events related to liquid nicotine exposure that occurred in 2018 among children under age 5. Updated information from this study may complement public education efforts and prevent liquid nicotine exposure among children.

Temporal Trends and Geographic Patterns of Lung Cancer Incidence by Histology in Thailand, 1990 to 2014

Purpose

Lung cancer is one of the most common cancers worldwide and in Thailand. We characterize and forecast region-specific patterns of lung cancer incidence by histology and sex.

Methods

We analyzed lung cancer incidence trends in Thailand by histology (adenocarcinoma [AdC]; squamous cell carcinoma [SCC]; and large-cell, small-cell, and other carcinomas) from 1990 to 2014 in four cancer registries in three regions (north, Chiang Mai Province and Lampang Province; northeast: Khon Kaen Province; south: Songkhla Province). Annual percent change (APC) was calculated to quantify the incidence rate trends using joinpoint regression. Age-period-cohort models were used to examine the temporal trends of AdC and SCC by age, calendar year, and birth cohort. We projected the incidence of AdC and SCC up to 2030 using three independent approaches: joinpoint, age-period-cohort, and Nordpred models.

Results

AdC incidence significantly increased from 1990 to 2012 in Chiang Mai males (APC, 1.3%), Songkhla males from 2004 to 2014 (APC, 2.5%), Songkhla females from 1990 to 2014 (APC, 5.9%), and Khon Kaen females from 2005 to 2014 (APC, 3.1%). Conversely, SCC incidence significantly decreased from 1990 to 2012 in Chiang Mai males and females (APC, −1.2% and −4.8%, respectively), Lampang males and females from 1993 to 2014 (APC, −5.4% and −5.2%, respectively), and Songkhla females from 1990 to 2014 (APC, −2.1%). In general, trends of AdC and SCC correlated more with birth cohort than with calendar year. Three projection models suggested that incidence rates of AdC in Songkhla may continue to increase until 2030.

Conclusion

Temporal trends of lung cancer by histology varied among regions in Thailand. Reduction of lung cancer incidence in Thailand likely will require prevention strategies tailored to each specific region.

Examining the Transitions Between Cigarette and Smokeless Tobacco Product Use in the United States Using the 2002-2003 and 2010-2011 Longitudinal Cohorts

Introduction

Smokeless tobacco (SLT) use in the United States has remained constant or even increased slightly in recent years, whereas smoking has continuously decreased. Characterization of transitions between tobacco products is critical to understand the reasons behind the continuing use of smokeless tobacco.

Methods

Two longitudinal cohorts of Tobacco Use Supplement of the Current Population Survey (TUS-CPS), 2002-2003 (n = 14996) and 2010-2011 (n = 18226), were used to examine transitions between cigarette and SLT use over 1-year periods. Weighted population percentages of four use categories (exclusive cigarette use, exclusive SLT use, dual use, and neither) were calculated for different demographic groups. Transition between use categories and quit rates by product were calculated for each cohort.

Results

Relative to 2002-2003, smoking quit rates of male exclusive smokers significantly increased in 2010-2011 (11.6% vs. 24.4%, p < .0001), but the corresponding SLT use quit rates remained stable (41.3% vs. 40.0%, p = .87). Similar patterns were found in females with smoking quit rates increasing considerably (12.3% vs. 24.2%, p < .0001). Smoking quit rates increased in most sociodemographic groups analyzed. Male SLT use quit rates were significantly lower in SLT exclusive users than in dual users in the 2010-2011 cohort (40.0% vs. 62.2%; p = .04), but smoking quit rates in exclusive smokers and in dual users were roughly equivalent (24.4% vs. 29.5%, p = .68).

Conclusions

Although smoking quit rates doubled overall and increased in most sociodemographic groups, SLT quit rates remained constant with little transition between products. Longer-term prospective data examining polytobacco use are needed to better understand transitions between tobacco products.

Implications

This study uses two longitudinal surveys to investigate changes in switching behaviors between tobacco products. We found that quit rates of self-reported smoking doubled between 2002-2003 and 2010-2011 in most sociodemographic groups in the United States, whereas in contrast quit rates of self-reported Smokeless Tobacco (SLT) use remained roughly constant. This explains in part the opposing trends of tobacco use by product in the United States, with smoking continuing its decrease, whereas SLT use remains constant. Moreover, smokers were unlikely to switch to other forms of tobacco compared to SLT users. Lastly, smoking cessation for dual users was not significantly different from that of exclusive smokers. Understanding transitions between smoking and SLT use is critical to assess the potential long-term impact of SLT use, and potentially that of other alternative tobacco products, on tobacco-related health outcomes.

An Examination of Device Types and Features Used by Adult Electronic Nicotine Delivery System (ENDS) Users in the PATH Study, 2015-2016

To date no study has reported U.S. nationally representative estimates of current ENDS users by device category (“open” vs. “closed” systems) nor their detailed use behaviors. We examined the proportion of current adult ENDS users (unweighted n = 2671) using either “closed” or “open” systems during Wave 3 (2015–2016) of the Population Assessment of Tobacco and Health (PATH) Study. Demographic characteristics, use patterns, and device characteristics were examined overall and by device type. Among the 5.0% of current users at Wave 3, 43.9% used closed systems and 53.7% used open systems. Compared to closed system users, open system users were more likely to be male (60.7% vs. 48.4%), aged 18–24 (30.4% vs. 21.4%), and non-Hispanic White (76.2% vs. 65.4%), recent former (9.9% vs. 5.6%) or long-term former (20.2% vs. 10.9%) smokers, and use ENDS daily (44.1% vs. 22.5%); they were less likely to be to be current daily smokers (31.7% vs. 48.0%) or never smokers (15.2% vs. 19.5%). Adult ENDS users were nearly evenly split on their use of closed versus open systems; however, several group differences were observed. Disentangling the relationship between device selection and subsequent use patterns remains a public health priority.

Associations of Cigarettes Smoked Per Day with Biomarkers of Exposure Among U.S. Adult Cigarette Smokers in the Population Assessment of Tobacco and Health (PATH) Study Wave 1 (2013-2014)

BACKGROUND

The dose-response relationships between number of cigarettes smoked per day (CPD) and health outcomes, such as cancer and heart disease, are well established, but much less is known about the relationships between CPD and biomarkers of exposure.

METHODS

We analyzed biomarker data by CPD from more than 2,700 adult daily cigarette smokers in Wave 1 of the Population Assessment of Tobacco and Health Study. Tobacco use categories consisted of exclusive cigarette smokers, dual cigarette and e-cigarette users, and dual cigarette and smokeless tobacco users.

RESULTS

Biomarker concentrations consistently increased with CPD for each tobacco user group, although concentrations tended to level off at high smoking levels, such as those at and above 20 CPD. Dual cigarette and e-cigarette users had higher levels of some biomarkers such as Total Nicotine Equivalents-2 (P = 0.0036) than exclusive cigarette smokers, and dual cigarette and smokeless tobacco users had higher levels of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (P < 0.0001) and N'-nitrosonornicotine (P = 0.0236) than exclusive cigarette smokers.

CONCLUSIONS

Among daily smokers, exposure to tobacco toxicants and constituents exhibits a dose-response relationship by number of cigarettes smoked, but the relationship is not necessarily linear in form. Dual users of cigarettes with either e-cigarettes or smokeless tobacco are exposed to higher levels of certain toxicants and carcinogens than exclusive cigarette smokers.

IMPACT

Availability of biomarker data by CPD may aid in comparisons between cigarette smoking and use of new and potentially reduced exposure tobacco products, which may result in different levels of constituent and toxicant exposure.

National estimates of poisoning events related to liquid nicotine in young children treated in US hospital emergency departments, 2013-2017

Background

An estimated 2 million youth (in 2017) and 7.9 million adults (in 2015) reported currently using electronic nicotine delivery systems (ENDS). Reports of poisoning events related to liquid nicotine (e-liquids) in ENDS have been on the rise, but current, nationally-representative estimates of hospital-treated poisoning cases related to e-liquid nicotine exposure in the United States (US) are lacking.

Findings

We used National Electronic Injury Surveillance System (NEISS) data from 2013 to 2017 to calculate national estimates with 95% confidence intervals (CIs) of poisoning incidents related to e-liquid nicotine exposure. From 2013 to 2017, an estimated 4745 poisoning cases related to e-liquids among children under age five were treated in US hospital emergency departments; the number of cases increased from 181 (95% CI: 0-369) in 2013 to 1736 (95% CI, 871-2602) in 2015 and then decreased to 411 (95% CI, 84-738) in 2017. Most of the cases were treated and released; 4.1% were admitted to the hospital. The most common route of exposure was through ingestion (96.9%), and 2.6% of the cases were through dermal exposure. The highest amounts of e-liquids or nicotine ingested were 118.2mL, 1 bottle, and 100 mg, and the most common symptoms (63.6%) related to nicotine poisoning were nausea and vomiting.

Conclusions

This study provides national estimates of poisoning cases associated with nicotine exposure from e-liquids among children under age five. Findings on e-liquid volume or nicotine dose, when available, provide important insights into exposures associated with toxicity in children. Since NEISS data do not include product codes specific to ENDS or provide information on poisoning severity, we used general keywords to capture these events, which might underestimate the population burden. Information from this study may complement efforts, such as public education, to prevent unintended exposure to nicotine in e-liquids among children.

Abstract GS5-05: Resistance to neoadjuvant chemotherapy in triple negative breast cancer mediated by a reversible drug-tolerant state

Approximately 50% of patients with localized triple negative breast cancer (TNBC) have substantial residual cancer burden following treatment with neoadjuvant chemotherapy (NACT), resulting in distant metastasis and death for most of these patients. While genomic and phenotypic intra-tumor heterogeneity are pervasive features of TNBCs at the time of diagnosis, the functional contributions of heterogeneous tumor cell populations to chemoresistance have not been elucidated.

To investigate tumor evolution accompanying NACT, we employed orthotopic patient-derived xenograft (PDX) models of treatment-naïve TNBC, which retain intra-tumor heterogeneity characteristic of human TNBC. We discovered that some PDX models initially exhibited partial sensitivity to standard front-line NACT (Adriamycin plus Cytoxan, AC). Following AC, residual tumors were resistant to chemotherapy but repopulated tumors with chemo-sensitive cells if left untreated, indicating that tumor cells possessed inherent plasticity. To identify the tumor cell subpopulation(s) conferring chemoresistance, we conducted barcode-mediated clonal tracking in three independent PDX models by introducing a high-complexity pooled lentiviral barcode library into PDX tumor cells which were then orthotopically engrafted into recipient mice. Strikingly, residual tumors maintained the same heterogeneous clonal architecture as naïve tumors. Concordantly, whole-exome sequencing revealed conservation of genomic subclonal architecture throughout treatment. These results were corroborated by genomic sequencing of serial biopsies pre- and post-AC obtained directly from TNBC patients enrolled on an ongoing clinical trial at MD Anderson (ARTEMIS; NCT02276443). Together, these studies revealed that genomically distinct pre-treatment subclones were equally capable of surviving AC to reconstitute tumors after treatment.

To identify functional addictions of residual tumor cells, we conducted histologic and transcriptomic profiling. Residual tumors following AC-treatment exhibited extensive fibrotic desmoplasia and tumor cell pleomorphism in both PDX models and in serial biopsies obtained from TNBC patients enrolled on the ARTEMIS trial. Strikingly, these AC-induced features were reverted upon regrowth of residual tumors in PDXs and in patients' tumors. Similarly, residual tumors exhibited unique transcriptomic features, many of which are also de-regulated in cohorts of human TNBCs undergoing chemotherapy treatment. These features were nearly completely reverted after tumors regrew, suggesting that the residual tumor state may be a unique and transient therapeutic window. Gene set enrichment analyses revealed that residual tumors had increased activation of oxidative phosphorylation and decreased glycolytic signaling. Pharmacologic targeting of oxidative phosphorylation with a small-molecule inhibitor of mitochondrial electron transport chain complex I (IACS-010759) significantly delayed the regrowth of AC-treated residual tumors in three independent PDX models. Collectively, these studies reveal that a reversible phenotypic state can confer chemoresistance in the absence of genomic selection and that the residual tumor state is a novel therapeutic window for chemo-refractory TNBC.

Citation Format: Echeverria GV, Ge Z, Seth S, Jeter-Jones SL, Zhang X, Zhou X, Cai S, Tu Y, McCoy A, Peoples M, Lau R, Shao J, Sun Y, Bristow C, Carugo A, Ma X, Harris A, Wu Y, Moulder S, Symmans WF, Marszalek JR, Heffernan TP, Chang JT, Piwnica-Worms H. Resistance to neoadjuvant chemotherapy in triple negative breast cancer mediated by a reversible drug-tolerant state [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr GS5-05.

Abstract P3-07-01: Towards a therapeutically relevant subtyping scheme for triple-negative breast cancer (TNBC), profiling results from A Randomized, TNBC Enrolling trial to confirm Molecular profiling Improves Survival (ARTEMIS)

Triple-negative breast cancer is a highly diverse group of cancers, with poor prognosis, and currently, there are no targeted drugs available in the clinic. In TNBC around 50% percent of the patients respond to chemotherapy, while, the other 50% percent relapse with poor prognosis. There is a need to understand better the targetable mechanisms driving TNBC via integrative analysis of gene-expression, copy-number, and mutational data.

Samples from 220 triple-negative breast cancer (TNBC) pts treated with NACT were prioritized for transcriptomic and genomic profiling. Non-negative matrix factorization was used on array-based profiling to identify six robust (ARTEMIS) subtypes. Comparing ARTEMIS subtypes with Vanderbilt subtypes, revealed significant overlap with 4/6 clusters while identifying two new clusters. Logistic regression on ssGSEA scores vs. subtypes revealed several pathways, selectively enriched specific subtypes. CL1/IM (Immune subtype), was enriched in INFg and INFa, while CL2 (MYC/mTOR), showed enrichment of several proliferation-related pathways. In addition, LAR and M (Mesenchymal) pts formed overlapping clusters, using either method.

Two new subtypes did not associate significantly with any of the previous subtypes. The majority of the tumors from the Vanderbilt BL2 and MSL were reclassified into a CL5 (ANGIO) cluster, which was enriched in angiogenesis geneset, including targetable genes like VEGF and FGFR. Also, an MYO (CL3) subtype was identified, with myogenesis-related genes. Of note, TIL (tumor infiltrating lymphocytes) and LAR quantification using IHC were associated with respective ARTEMIS subtypes. Finally, the IM subtype was significantly associated with higher rates of RCB 0-I and the M (CL4) subtype was associated with higher rates of RCB II-III, irrespective of the neoadjuvant treatment regimen.

ARTEMIS subtypes are a novel classification system for TNBC that is focused on therapeutic translation. Further, we show a possibility to classify previously un-classified (UNS) tumors, which will be validated using additional cohorts (TCGA/METABRIC).

Citation Format: Seth S, Huo L, Rauch G, Lau R, Gilcrease M, Adrada B, Piwnica-Worms H, Symmans WF, Draetta G, Futreal AP, Moulder S, Chang JT. Towards a therapeutically relevant subtyping scheme for triple-negative breast cancer (TNBC), profiling results from A Randomized, TNBC Enrolling trial to confirm Molecular profiling Improves Survival (ARTEMIS) [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P3-07-01.

Biomarkers of Exposure among U.S. Adult Cigar Smokers: Population Assessment of Tobacco and Health (PATH) Study Wave 1 (2013-2014)

BACKGROUND

Given the diverse cigar market and limited data on biomarker patterns by cigar type, we compared biomarkers of nicotine and tobacco toxicants among cigar smokers and other groups.

METHODS

Using Wave 1 urinary biomarker data from 5,604 adults in the Population Assessment of Tobacco and Health (PATH) Study, we compared geometric mean concentrations among cigar-only smokers (all cigars and separately for traditional, cigarillo, and filtered cigars), cigarette-only smokers, dual cigar/cigarette smokers, and never users of tobacco. We calculated geometric mean ratios comparing groups with never users adjusting for sex, age, race/ethnicity, education and creatinine.

RESULTS

Some day cigar-only smokers had lower biomarker concentrations than every day cigar-only smokers, but higher than never users. Every day cigar-only smokers (n = 61) had lower TNE-2 (cotinine+trans-3'-hydroxycotinine) compared to every day cigarette-only (n = 2217; P < 0.0001) and dual cigar/cigarette smokers (n = 601; P < 0.0001). Several biomarkers, including NNAL (NNK metabolite) and CYMA (metabolite of acrylonitrile), were comparable in these groups. In exploratory analyses, every day filtered cigar-only (n = 7) smokers had higher biomarker concentrations compared with every day traditional cigar-only smokers (n = 12) and cigarillo-only smokers (n = 24). Every day smokers of each cigar type were similar to exclusive cigarette smokers. For some biomarkers, particularly for every day filtered cigar-only smokers, concentrations were higher.

CONCLUSIONS

For some biomarkers, every day cigar-only smokers were comparable with every day cigarette-only smokers. Exploratory analyses suggest that biomarkers vary by cigar type with every day filtered cigar-only smokers having the highest concentrations.

IMPACT

High exposure to harmful constituents among cigar smokers is a continuing health issue.

Smokeless tobacco use and circulatory disease risk: a systematic review and meta-analysis

Objective

Smokeless tobacco use is a public health issue throughout the world, but reviews and analyses of circulatory disease risks associated with smokeless tobacco use may be outdated or incomplete. This study provides a thorough and comprehensive review and meta-analysis of circulatory disease risks in high-income countries, including recently published study estimates.

Methods

We conducted a systematic review of studies of circulatory disease risks associated with smokeless tobacco use in Europe and North America that were identified from electronic databases and reference lists. Study estimates were extracted by region, smokeless tobacco use status, cigarette smoking status, and circulatory condition and combined in meta-analysis using a random-effects model. We used the Newcastle-Ottawa scale to assess study quality and risk of bias.

Results

We identified 17 relevant cohort studies, two pooled analyses, five case-control studies and one cross-sectional analysis. We found increased risk of heart disease (relative risk (RR) 1.17, 95% CI 1.09 to 1.27) and stroke (RR 1.28, 95% CI 1.01 to 1.62) among US smokeless tobacco users compared with non-users. Increased circulatory disease risk was not observed among Swedish smokeless tobacco users.

Conclusion

US smokeless tobacco users were found to have increased risk of heart disease and stroke.

Electronic nicotine delivery system (ENDS) battery-related burns presenting to US emergency departments, 2016

BACKGROUND

Currently, an estimated 7.9 million US adults use electronic nicotine delivery systems (ENDS). Although published reports have identified fires and explosions related to use of ENDS since 2009, these reports do not provide national estimates of burn injuries associated with ENDS batteries in the US.

FINDINGS

We analyzed nationally representative data provided in the National Electronic Injury Surveillance System (NEISS) to estimate the number of US emergency department (ED) visits for burn injuries associated with ENDS batteries. We reviewed the case narrative field to gain additional insights into the circumstances of the burn injury. In 2016, 26 ENDS battery-related burn cases were captured by NEISS, which translates to a national estimate of 1007 (95%CI: 357-1657) injuries presenting in US EDs. Most of the burns were thermal burns (80.4%) and occurred to the upper leg/lower trunk (77.3%). Examination of the case narrative field indicated that at least 20 of the burn injuries occurred while ENDS batteries were in the user's pocket.

CONCLUSIONS

Our study provides valuable information for understanding the current burden of ENDS battery-related burn injuries treated in US EDs. The nature and circumstances of the injuries suggest these incidents were unintentional and would potentially be prevented through battery design requirements, battery testing standards and public education related to ENDS battery safety.

Abstract P5-05-01: A molecularly annotated collection of breast cancer patient-derived xenograft models aligned with ongoing clinical trials built from fine needle aspiration samples throughout neoadjuvant treatment

BACKGROUND: Patient-derived xenograft (PDX) models of breast cancer replicate the diverse histologic and molecular features of patient tumors and provide a renewable source of human tumor tissue. However, collection of tissue by core needle biopsy is problematic due to patient discomfort, bleeding risk and the limited number of passes a patient can tolerate. Several studies have catalogued the maintenance of molecular features of patient tumors in PDX models of breast cancer.

METHODS: To support the neoadjuvant molecular diagnostic and drug development program in triple negative breast cancer (TNBC), a pilot study was conducted to determine if fine needle aspiration (FNA) could be used for building PDX models. Subsequently, PDX models are being established in alignment with ongoing clinical trials at MDACC. The molecular evolution of patient's tumors, matched with PDXs engrafted from their tumors, is under study throughout the neoadjuvant treatment of TNBC using RNA sequencing, whole-exome sequencing, deep sequencing of cancer genes, and histologic analyses.

RESULTS: To date, 20 established PDX models have been developed and stable PDX models continue to be generated at a rate of 2-3 per month. Several of these models are derived from serial FNAs derived from patients throughout neoadjuvant treatment. These models retain histologic and molecular features of the original patient tumors. Serial patient biopsies, matched with PDX models, have enabled measurement of the mutational and transcriptomic evolution in vivo of TNBC undergoing neoadjuvant treatment.

We have standardized the use of FNAs to generate PDX models both pre- and post-neoadjuvant therapy in the following ongoing neoadjuvant clinical trials:

1. MDACC 2014-0185 (PI Stacy Moulder, 360 patients), 'ARTEMIS: A Randomized TNBC-Enrolling trial to confirm Molecular profiling Improves Survival'

2. MDACC 2014-0045 (PI Jennifer Litton, 20+ patients), 'A pilot study of BMN673 as a neoadjuvant study in patients with a diagnosis of invasive breast cancer and a deleterious BRCA mutation'

CONCLUSION: We demonstrated that PDX models from tissue collected by FNA recapitulate the biology and clinical course of the patient's tumor. Sequencing analyses revealed that neoadjuvant chemotherapy and PDX engraftment enrich for cancer gene mutations. We observe association of the rate of successful PDX engraftment with clinical parameters such as the patient's residual cancer burden (RCB) status at the time of surgery (upon completion of neoadjuvant treatment). In addition, we observe that PDX models derived from serial patient biopsies throughout treatment are more resistant to chemotherapy treatment. These models recapitulate the variety of chemotherapy responses observed in patients with TNBC and serve as powerful tools for preclinical biomarker and discovery studies.

Citation Format: Echeverria GV, Cai S, Tu Y, McCoy A, Lau R, Redwood A, Rauch G, Adrada B, Candelaria R, Santiago L, Thompson A, Litton J, Moulder S, Symmans F, Chang JT, Piwnica-Worms H. A molecularly annotated collection of breast cancer patient-derived xenograft models aligned with ongoing clinical trials built from fine needle aspiration samples throughout neoadjuvant treatment [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P5-05-01.

Abstract P4-03-02: Characterizing and targeting chemoresistant subclones in patient-derived xenograft models of triple negative breast cancer

Fifty percent of all triple negative breast cancer (TNBC) patients harbor significant residual tumor burden following treatment with standard neoadjuvant chemotherapy (NACT), resulting in poor prognosis. Recent studies in TNBC have revealed extensive intra-tumoral heterogeneity at the time of diagnosis and throughout disease progression, but the relative contributions of these heterogeneous populations of tumor cells to chemoresistance are not well understood.

The primary tumor, dermal metastasis, and germline reference were obtained from a patient with untreated metastatic TNBC. Tumor cells were engrafted into the humanized mammary fat pads of NOD/SCID mice to establish PDX models of the primary (PIM001-P) and metastatic (PIM001-M) tumors. RNA sequencing and whole-exome sequencing (WES), performed on the patient's primary and metastatic tumors and the first- and third- passage PDX models revealed transcriptomic profiles and subclonal heterogeneity of the patient's tumors were recapitulated in the PDX models.

Treatment of mice engrafted with PIM001-P tumors with NACT (Adriamycin plus cyclophosphamide, AC) resulted in partial response, the magnitude of which was diminished in mice bearing PIM001-M tumors. Tumor subclones were tracked during chemotherapy treatment in mice engrafted with PIM001-P tumors using lentiviral non-targeting DNA barcodes. Residual tumors maintained the clonal architecture of untreated tumors, and deep WES revealed stable maintenance of somatic mutant allele frequencies throughout treatment. Therefore, selection of pre-existing resistant clones did not lead to AC resistance in this model. Interestingly, only 25% of residual tumor clones contributed to primary relapse once treatment was halted, suggesting only a subpopulation of tumor cells was able to reconstitute the tumor.

RNA sequencing and reverse phase protein array revealed that while vehicle-treated and regrown tumors were highly similar, residual tumors harbored a unique profile characterized by numerous significant alterations in RNA and protein levels. Together, these results suggest that residual tumors enter into a transient drug-resistant state that is reversible. Residual tumors were enriched for alterations in pathways such as metabolism, extracellular matrix remodeling, and cell-cell communication. Pharmacologic targeting of the residual tumor state with an inhibitor of mitochondrial oxidative phosphorylation led to significant inhibition of tumor regrowth following AC treatment. Additional vulnerabilities identified in residual tumors are being targeted therapeutically with the goal of eradicating residual tumor cells.

Citation Format: Echeverria GV, Seth S, Ge Z, Sun Y, DiFrancesco E, Lau R, Marszalek J, Moulder S, Symmans F, Heffernan TP, Chang JT, Piwnica-Worms H. Characterizing and targeting chemoresistant subclones in patient-derived xenograft models of triple negative breast cancer [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P4-03-02.

Molecular detection and genotyping of Anaplasma spp. and Theileria spp. infections in sheep and cattle from the northeast region of China

Anaplasmosis and theileriosis are significant tick-borne diseases threatening the livestock industry worldwide. In the present study, we screened 127 cattle and 115 sheep blood DNA samples from northeastern China for Theileria and Anaplasma pathogens by polymerase chain reaction (PCR) using species-specific primers. The result showed that only Theileria orientalis and Anaplasma ovis were detected, with a prevalence of 2.9% for T. orientalis in cattle and 57.4% for A. ovis in sheep. Fragments of Anaplasma ovis major surface protein 4 (AoMSP4) and Theileria orientalis major piroplasm surface protein (ToMPSP) genes were sequenced for phylogenetic analysis. Sequence analysis showed that the AoMSP4 gene was conserved, with 100% sequence identity value among sheep samples. However, the ToMPSP gene was relatively diverse, with sequence identity ranging from 87.6%-99l.0% among cattle samples. Phylogenetic analysis showed that the ToMPSP gene sequences isolated from 4 cattle samples were classified into type 1, type 2 and type 7, while the AoMSP4 gene sequences obtained from 66 sheep were classified into genotype I, according to the neighbour-joining distance method. This study provides important data for understanding the epidemiology of tick-borne diseases and genetic diversity of these pathogens in the northeast region of China.

CATTLE (CAncer treatment treasury with linked evidence): An integrated knowledge base for personalized oncology research and practice

Despite the existence of various databases cataloging cancer drugs, there is an emerging need to support the development and application of personalized therapies, where an integrated understanding of the clinical factors and drug mechanism of action and its gene targets is necessary. We have developed CATTLE (CAncer Treatment Treasury with Linked Evidence), a comprehensive cancer drug knowledge base providing information across the complete spectrum of the drug life cycle. The CATTLE system collects relevant data from 22 heterogeneous databases, integrates them into a unified model centralized on drugs, and presents comprehensive drug information via an interactive web portal with a download function. A total of 2,323 unique cancer drugs are currently linked to rich information from these databases in CATTLE. Through two use cases, we demonstrate that CATTLE can be used in supporting both research and practice in personalized oncology.

Abstract P4-06-03: An annotated collection of pre- and post-therapy breast cancer patient-derived xenograft models built from fine needle aspiration samples aligned with ongoing clinical trials documenting response to treatment

BACKGROUND: Patient-derived xenograft (PDX) models of breast cancer replicate the diverse histologic and molecular features of patient tumors and provide a renewable source of human tumor tissue; however collection of tissue by core needle biopsy is problematic due to patient discomfort, bleeding risk and the limited number of passes a patient can tolerate. In addition, FDA guidelines caution that multiple core needle biopsies could lead to an overestimation of the true pCR rate in neoadjuvant trials.

METHODS: To support the neoadjuvant molecular diagnostic and drug development program in TNBC, a pilot study was conducted to determine if fine needle aspiration (FNA) could be used for building PDX models. Prior to engraftment, FNA samples were analysed for cell number and viability.

RESULTS: Six PDX models were successfully generated from eight individual tumor samples. These models retain histologic and molecular features of the original patient tumors as determined by immunohistochemistry, RNA expression profiling, and deep whole-exome and targeted gene sequencing. In addition, the tested PDX models recapitulate the responses to therapies across multiple chemotherapeutic agents.

Based on this success, we have standardized the use of FNAs to generate PDX models both pre- and post-therapy in two ongoing neoadjuvant clinical trials:

1. MDACC 2014-0185 (PI Stacy Moulder, 360 patients), 'Improving outcomes in TNBC using molecular triaging and diagnostic imaging to guide neoadjuvant therapy'

2. MDACC 2014-0045 (PI Jennifer Litton, 20+ patients), 'A pilot study of BMN673 as a neoadjuvant study in patients with a diagnosis of invasive breast cancer and a deleterious BRCA mutation'

 FNA cells (x10^4)Cell viability (%)Total viable cells (x10^4)Study entry biopsy (n=67)144.5050.6544.14Post treatment biopsy (n=16)47.0732.5428.38

To date, treatment-naïve primary tumor samples from 67 patients enrolled onto these neoadjuvant trials, and 16 matched non-responsive post treatment tumor samples have been analysed for cell count and viability (table below) prior to being engrafted into the humanized mammary fat pads of NOD/SCID mice.

CONCLUSION: We have demonstrated success in using FNAs to build PDX models that recapitulate the biology and clinical course of the original tumor. In our pilot study, we successfully generated six PDX models using FNA for TNBC, including some harboring deleterious BRCA1/2 mutations. Because of the high concordance in histologic, genomic, and clinical attributes, we are now using this approach to develop a rich resource of pre- and post-treatment PDX models for the investigation of therapeutic resistance.

Citation Format: Echeverria GV, Chang JT, Cai S, Tu Y, McCoy A, Lau R, Redwood A, Kaffiabasabadi S, Rauch GM, Adrada BE, Jennifer L, Moulder SL, Symmans WF, Piwnica-Worms H. An annotated collection of pre- and post-therapy breast cancer patient-derived xenograft models built from fine needle aspiration samples aligned with ongoing clinical trials documenting response to treatment [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P4-06-03.

Phosphorylation of serine 367 of FOXC2 by p38 regulates ZEB1 and breast cancer metastasis, without impacting primary tumor growth

Metastatic competence is contingent upon the aberrant activation of a latent embryonic program, known as the epithelial-mesenchymal transition (EMT), which bestows stem cell properties as well as migratory and invasive capabilities upon differentiated tumor cells. We recently identified the transcription factor FOXC2 as a downstream effector of multiple EMT programs, independent of the EMT-inducing stimulus, and as a key player linking EMT, stem cell traits and metastatic competence in breast cancer. As such, FOXC2 could serve as a potential therapeutic target to attenuate metastasis. However, as FOXC2 is a transcription factor, it is difficult to target by conventional means such as small-molecule inhibitors. Herein, we identify the serine/threonine-specific kinase p38 as a druggable upstream regulator of FOXC2 stability and function that elicits phosphorylation of FOXC2 at serine 367 (S367). Using an orthotopic syngeneic mouse tumor model, we make the striking observation that inhibition of p38-FOXC2 signaling selectively attenuates metastasis without impacting primary tumor growth. In this model, circulating tumor cell numbers are significantly reduced in mice treated with the p38 inhibitor SB203580, relative to vehicle-treated counterparts. Accordingly, genetic or pharmacological inhibition of p38 decreases FOXC2 protein levels, reverts the EMT phenotype and compromises stem cell attributes in vitro. We also identify the EMT-regulator ZEB1-known to directly repress E-cadherin/CDH1-as a downstream target of FOXC2, critically dependent on its activation by p38. Consistent with the notion that activation of the p38-FOXC2 signaling axis represents a critical juncture in the acquisition of metastatic competence, the phosphomimetic FOXC2(S367E) mutant is refractory to p38 inhibition both in vitro and in vivo, whereas the non-phosphorylatable FOXC2(S367A) mutant fails to elicit EMT and upregulate ZEB1. Collectively, our data demonstrate that FOXC2 regulates EMT, stem cell traits, ZEB1 expression and metastasis in a p38-dependent manner, and attest to the potential utility of p38 inhibitors as antimetastatic agents.

Trends and Factors Related to Smokeless Tobacco Use in the United States

BACKGROUND

While declines in smoking prevalence in the United States have been well documented, trends in smokeless tobacco (SLT) use are less clear. This study updates previous analyses of US SLT use prevalence to better understand trends and factors related to SLT use.

METHODS

We used the Tobacco Use Supplement of the Current Population Survey (TUS-CPS) to examine trends and factors related to SLT use using joinpoint and logistic regression models. SLT consumption from 1985 to 2011 was obtained from the 2011 Federal Trade Commission Smokeless Tobacco Report. Sensitivity analyses were conducted for assessing the impact of varying frequency definitions of SLT use.

RESULTS

Decreasing trends in smoking and SLT prevalence overall were observed from 1992 to 2003 independently of use definition. SLT prevalence in the total adult population significantly decreased at an annual percent change (APC) of 4.5% per year from 1992 to 2003, but has been approximately constant ever since. Similar patterns were also found in adult males (APC = -4.4%) and young males (APC = -9.5%). SLT per capita consumption decreased significantly from 1991 to 1999 (APC = -2.2%), but has since decreased at only 0.35% per year (1999-2011). SLT use was found to be associated with former smoker status, younger age, white race, living in rural areas, residence in the South, lower education and unemployment, adjusting for other factors.

CONCLUSIONS

Declines in SLT use were found in the United States, suggesting tobacco control has had positive impacts, but these have slowed since 2003. Targeting tobacco control policies to at-risk demographic groups is needed to further reduce SLT use in the United States.

IMPLICATIONS

This study confirms that the declines in SLT use prevalence stopped in 2003 across different demographic groups, consistent with trends in SLT consumption. In addition, the longer period of analysis in comparison with earlier studies allows for quantitative characterization of SLT use trends using joinpoint regression. The study also shows the impact of different SLT use definitions in determining tobacco product use prevalence and trends.

The ERK-ZEB1 pathway mediates epithelial-mesenchymal transition in pemetrexed resistant lung cancer cells with suppression by vinca alkaloids

High thymidylate synthase (TS) level in cancer tissue is considered to result in resistance to pemetrexed therapy for advanced stages of nonsquamous non-small cell lung cancers. To further investigate the mechanism of pemetrexed resistance and potential prognostic outcomes in lung cancer, we established pemetrexed-resistant lung adenocarcinoma cell sublines from CL1 harboring a mutated TP53 gene (R248W) and A549 harboring wild-type TP53. We found the TS expression is upregulated in both pemetrexed-resistant sublines and the reduced TS level achieved through shRNA inhibition resulted in higher pemetrexed sensitivity. We also demonstrated that the acquisitions of pemetrexed resistance enhances epithelial–mesenchymal transition (EMT) in vivo with a mice animal model and in vitro with CL1 and A549 sublines, which was associated with upregulation of ZEB1 which, in turn, downregulates E-cadherin and upregulates fibronectin. When ERK1/2 phosphorylation was reduced by an inhibitor (U0126) or siRNA inhibition, both pemetrexed-resistant sublines reduced their migration and invasion abilities. Therefore, the ERK-mediated pathways induce apoptosis with pemetrexed treatment, and may in turn mediate EMT when cancer cells are resistant to pemetrexed. We further demonstrated that the growth of pemetrexed-resistant tumors could be inhibited by vinblastine in vivo and vincristine in vitro. Our data indicate that pemetrexed resistance could be relieved by non-cross-resistant chemotherapeutic drugs such as vinca alkaloids and might be independent to TP53 status. Furthermore, the phosphorylation of ERK was reduced by vincristine. This finding provides a new insight for overcoming pemetrexed resistance and metastasis by application of vinca alkaloids.

Multistage carcinogenesis and the incidence of thyroid cancer in the US by sex, race, stage and histology

Background

Thyroid cancer has the fastest growing incidence in the US. However, the underlying causes are still under debate.

Methods

We analyzed thyroid cancer incidence in the SEER-9 registry from 1973-2010 using multistage carcinogenesis and age-period-cohort models. Multistage models were used to investigate differences in initiation, promotion and malignant conversion rates of thyroid tumors by sex, race, stage, and histology. Models were adjusted for period and cohort trends to investigate the contributions of each factor, and determine whether birth- or diagnosis-year better correlate with observed incidence patterns.

Results

Significant increases in thyroid cancer incidence by period or calendar-year were found for all sex, race, stage and histology combinations, particularly for localized cases (a 3- and 4-fold increase from 1973-2010 for females and males, respectively). Multistage analyses suggest that the 3-fold higher incidence in women could be explained by 1.5-fold higher initiation and promotion rates. Analyses by race suggest that the lower incidence in blacks can be attributed to lower promotion rates versus whites. Analysis by histology showed considerable decreases in follicular cancer incidence by birth-cohort since the early 1900s.

Conclusions

Multistage modeling suggests that variations in thyroid cancer initiation and promotion can explain the observed differences in incidence by sex, race and histology. The consistent increases in incidence by calendar-year for all sex-race-histology-stage combinations suggest that the rise may be predominantly due to more intensive screening-diagnostics, although an environmental factor may be also at play. Our analyses constitute a first step towards the development of thyroid cancer natural history models.

Electronic supplementary material

The online version of this article (doi:10.1186/s12889-015-2108-4) contains supplementary material, which is available to authorized users.

Site-specific factors for cancer of the corpus uteri from SEER registries: collaborative stage data collection system, version 1 and version 2

BACKGROUND

Uterine cancer is the fourth leading cancer among US women. Changes in uterine cancer staging were made from the American Joint Committee on Cancer (AJCC) 6th to 7th edition staging manuals, and 8 site-specific factors (SSFs) and 3 histologic schemas were introduced. Carcinomas account for 95% of cases and are the focus of this report.

METHODS

Distributions of SSF values were examined for 11,601 cases of malignant cancer of the corpus uteri and uterus, NOS (not otherwise specified) diagnosed in Surveillance, Epidemiology, and End Results (SEER) Program registries during 2010. AJCC 6th and 7th edition staging distributions were compared for 11,176 cases using data in both staging systems. AJCC 6th edition staging distributions during 2004-2010 were examined. AJCC 7th edition SSFs required by SEER were International Federation of Gynecology and Obstetrics stage (SSF1), peritoneal cytology (SSF2), number of positive pelvic lymph nodes (SSF3), number of pelvic lymph nodes examined (SSF4), number of positive para-aortic lymph nodes (SSF5), and number of para-aortic lymph nodes examined (SSF6).

RESULTS

For SSFs related to lymph nodes, a third of cases were classified as "not applicable," reflecting that lymph node dissection is not indicated for cases with stage1A and stage 4 diagnoses. AJCC 7th edition criteria assigned more cases to stage I (72.9%) than AJCC 6th edition criteria (68.7%). Annual counts significantly increased during 2004-2010, as did counts for AJCC 6th edition stages INOS, IA, IB, IC, IIIA, IIIB, IIIC, and IVB. The proportion of cases diagnosed with stage I cancer was stable, whereas stages II and IV decreased and stage III increased.

CONCLUSIONS

Five SSFs were suitable for analysis: peritoneal cytology results (SSF2), numbers of positive pelvic lymph nodes (SSF3), pelvic lymph nodes examined (SSF4), positive para-aortic lymph nodes (SSF5), and para-aortic lymph nodes examined (SSF6).

Tree-based model for thyroid cancer prognostication

BACKGROUND

Death is uncommon in thyroid cancer patients, and the factors important in predicting survival remain inadequately studied. The objective of this study was to assess prognostic effects of patient, tumor, and treatment factors and to determine prognostic groups for thyroid cancer survival.

METHODS

Using data from the Surveillance, Epidemiology, and End Results Program (SEER), we evaluated overall and disease-specific survival (DSS) in 43 392 well-differentiated thyroid cancer patients diagnosed from 1998 through 2005. Multivariable analyses were performed using Cox proportional hazards regression, survival trees, and random survival forest. Similar analyses were performed using National Cancer Data Base data, with overall survival (OS) evaluated in 131 484 thyroid cancer patients diagnosed from 1998 through 2005. Relative importance of factors important to survival was assessed based on the random survival forest analyses.

RESULTS

Using survival tree analyses, we identified 4 distinct prognostic groups based on DSS (P < .0001). The 5-year DSS of these prognostic groups was 100%, 98%, 91%, 64%, whereas the 10-year survival was 100%, 96%, 85%, and 50%. Based on random survival forest analyses, the most important factors for DSS were SEER stage and age at diagnosis. For OS, important prognostic factors were similar, except age at diagnosis demonstrated marked importance relative to SEER stage. Similar results for OS were found using National Cancer Data Base data.

CONCLUSION

This study identifies distinct prognostic groups for thyroid cancer and illustrates the importance of patient age to both disease-specific and OS. These findings have implications for patient education and thyroid cancer treatment.

GD3 synthase regulates epithelial-mesenchymal transition and metastasis in breast cancer

The epithelial-mesenchymal transition (EMT) bestows cancer cells with increased stem cell properties and metastatic potential. To date, multiple extracellular stimuli and transcription factors have been shown to regulate EMT. Many of them are not druggable and therefore it is necessary to identify targets, which can be inhibited using small molecules to prevent metastasis. Recently, we identified the ganglioside GD2 as a novel breast cancer stem cell marker. Moreover, we found that GD3 synthase (GD3S)--an enzyme involved in GD2 biosynthesis--is critical for GD2 production and could serve as a potential druggable target for inhibiting tumor initiation and metastasis. Indeed, there is a small molecule known as triptolide that has been shown to inhibit GD3S function. Accordingly, in this manuscript, we demonstrate that the inhibition of GD3S using small hairpin RNA or triptolide compromises the initiation and maintenance of EMT instigated by various signaling pathways, including Snail, Twist and transforming growth factor-β1 as well as the mesenchymal characteristics of claudin-low breast cancer cell lines (SUM159 and MDA-MB-231). Moreover, GD3S is necessary for wound healing, migration, invasion and stem cell properties in vitro. Most importantly, inhibition of GD3S in vivo prevents metastasis in experimental as well as in spontaneous syngeneic wild-type mouse models. We also demonstrate that the transcription factor FOXC2, a central downstream effector of several EMT pathways, directly regulates GD3S expression by binding to its promoter. In clinical specimens, the expression of GD3S correlates with poor prognosis in triple-negative human breast tumors. Moreover, GD3S expression correlates with activation of the c-Met signaling pathway leading to increased stem cell properties and metastatic competence. Collectively, these findings suggest that the GD3S-c-Met axis could serve as an effective target for the treatment of metastatic breast cancers.