Ryan, Bríd M.

Abstract Background: Somatic EGFR mutations define a subset of non–small cell lung cancers (NSCLC) that have clinical impact on NSCLC risk and outcome. However, EGFR-mutation-status is often missing in epidemiologic datasets. We developed and tested pragmatic approaches to account for EGFR-mutation-status based on variables commonly included in epidemiologic datasets and evaluated the clinical utility of these approaches. Methods: Through analysis of the International Lung Cancer Consortium (ILCCO) epidemiologic datasets, we developed a regression model for EGFR-status; we then applied a clinical-restriction approach using the optimal cut-point, and a second epidemiologic, multiple imputation approach to ILCCO survival analyses that did and did not account for EGFR-status. Results: Of 35,356 ILCCO patients with NSCLC, EGFR-mutation-status was available in 4,231 patients. A model regressing known EGFR-mutation-status on clinical and demographic variables achieved a concordance index of 0.75 (95% CI, 0.74–0.77) in the training and 0.77 (95% CI, 0.74–0.79) in the testing dataset. At an optimal cut-point of probability-score = 0.335, sensitivity = 69% and specificity = 72.5% for determining EGFR-wildtype status. In both restriction-based and imputation-based regression analyses of the individual roles of BMI on overall survival of patients with NSCLC, similar results were observed between overall and EGFR-mutation-negative cohort analyses of patients of all ancestries. However, our approach identified some differences: EGFR-mutated Asian patients did not incur a survival benefit from being obese, as observed in EGFR-wildtype Asian patients. Conclusions: We introduce a pragmatic method to evaluate the potential impact of EGFR-status on epidemiological analyses of NSCLC. Impact: The proposed method is generalizable in the common occurrence in which EGFR-status data are missing.

1512 Background: Tobacco smoking profoundly impacts LC risk; however, data are limited as to what extent SC prior to diagnosis impacts LC overall survival (OS) and lung cancer specific survival (LCSS). LC screening offers a possible teachable moment, but there is uncertainty of SC benefits after a lifetime of smoking. We use the ILCCO database to answer if SC prior to LC dx is associated with better OS and LCSS, considering time since smoking cessation (TSSC). Methods: Using individual data, analysis was performed on 17 ILCCO studies with available TSSC to estimate survival using univariable analysis and models of stage-adjusted and cumulative smoking-adjusted multivariable analysis. Adjusted Hazard Ratios (aHR) from Cox models, cubic spline smooth curves and Kaplan-Meier curves were created. Sensitivity analysis was performed for TSSC and LCSS on 13 studies. Results: Of 34649 patients, 14322 (41%) were current smokers 14273 (41%) ex-smokers and 6054 (18%) never smokers at diagnosis. We confirmed that ex-smokers (aHR 0.88 CI 0.86-0.91) and never smokers (aHR 0.76 CI 0.73-0.8) improved OS compared to current smokers. Amongst ex-smokers, < 2y TSSC (aHR 0.88 CI 0.82-0.94), 2-5y TSSC (aHR 0.83 CI 0.77-0.90) and > 5y TSSC (aHR 0.8 CI 0.76-0.84) had improved OS compared to CS. Sensitivity analysis showed a trend towards improved LCSS survival for < 2y TSSC (aHR 0.95 CI 0.86-1.05) and 2-5y TSSC (aHR 0.93 CI 0.83-1.04), whereas > 5y TSSC significantly improved LCSS by 15% (aHR 0.85 CI 0.78-0.92). To mimic the LC screening participants, in analysis of > 30 pack-years individuals, associations were strikingly strong: < 2y TSSC had improved OS by 14% (aHR 0.86 CI 0.80-0.93); 2-5y TSSC by 17% (aHR 0.83 CI 0.76-0.90); and > 5 TSSC by 22% (aHR 0.78 CI 0.74-0.83), compared to current smokers; for < 30 packs-years, a trend towards better OS was observed for < 2y TSSC (aHR 0.95 CI 0.92-1.02) and 2-5y TSSC (aHR 0.86 CI 0.74-1.01), whereas > 5y TSSC improved OS by 23% (aHR 0.77 CI 0.72-0.82). Conclusions: Among ex-smokers, the risk of overall death was reduced by 12% on < 2y TSSC, 17% on 2-5y TSSC and 20% > 5y TSSC, whereas for LCSS, the benefit was significant only for > 5y TSCC, compared to current smokers at time of diagnosis. Here we demonstrate that convincing screening participants to quit smoking at any point of their trajectory, even just prior to dx such as < 2y TSSC, improved OS, and LCSS benefit was present beyond 5y of quitting. These relationships are independent of pack-years, age, across all stages and other prognostic variables.

1562 Background: In Caucasian-predominant populations, overweight or obese NSCLC pts (BMI≥25-kg/m2) have better prognosis while underweight (BMI≤18.5-kg/m2) pts have a worse prognosis. A large pooled sample allowed us to evaluate the role of ethnicity in this BMI-NSCLC OS relationship. Methods: Using individual data, survival analysis was performed on 15 ILCCO studies, assessing the interactions between ethnicity and BMI on overall survival (OS). Adjusted Hazard Ratios (aHR) from Cox models and adjusted penalized smoothing spline plots were generated. Results: Among 13416 (77%) Caucasian, 2975 (17%) Asian, and 935 (5%) Black NSCLC pts analyzed, we confirmed that for all pts, being underweight at NSCLC diagnosis was associated with worse OS (aHR=1.68, CI 1.5-1.8, p<0.001), while overweight/obese pts had improved survival (aHR 0.89, CI 0.8-0.9, p<0.001), when compared to pts with normal BMI. In general, Black pts had poorer OS than Caucasian pts (aHR 1.26 CI 1.1-1.4, p<0.001). However, the BMI-OS relationship differed according to ethnicity (BMI-ethnicity interaction, p=0.009): Caucasian underweight pts had poorer OS (aHR 1.67, CI 1.5-1.8, P<0.001) while overweight/obese pts had improved OS (aHR 0.89, CI 0.8-0.9, P<0.001). In Asian pts, these two associations were aHR 1.15, CI 0.8-1.5, P=0.33, and aHR 0.91, CI 0.7-1.1, P=0.32, respectively. In Black pts, these two associations were aHR 1.06, CI 0.7-1.5, p=0.73 and 0.75, CI 0.6-0.8 p<0.001, respectively. For overweight/obese patients, as BMI rises from 25-kg/m2 through 45-kg/m2, the prognosis worsens for Caucasian pts, remains stable for Asian pts, but improves for Black pts. Conclusions: InCaucasian pts, being underweight had a greater negative impact on OS than for Asian or Black pts, while being obese had a greater beneficial impact in Blacks than in other ethnic groups. These ethnic differences likely reflect genetically-informed muscle/adipose tissue distributions, where Black pts may have less sarcopenic obesity than other ethnicities. In future prognostic studies, BMI relationships must account for ethnic differences.

Abstract Lung cancer is the leading cancer diagnosis worldwide and the number one cause of cancer deaths. Exposure to cigarette smoke, the primary risk factor in lung cancer, reduces epithelial barrier function and increases susceptibility to infections. Herein, we hypothesized that somatic mutations together with cigarette smoke create a dysbiotic microbiota that is associated with lung carcinogenesis. Using lung tissue from controls (n=33) or cancer cases (n=143), we conducted 16S rRNA gene sequencing (MiSeq), with RNA-seq data from lung cancer cases in The Cancer Genome Atlas (n=1112) serving as the validation cohort. We demonstrate a lower alpha diversity in normal lung as compared to non-tumor adjacent or tumor tissue, indicating a shift in the overall microbial community in lung cancer patients as compared to those without cancer. Lung cancer cases were classified by the relative abundance of two taxa, Variovorax and Streptococcus, with an increase in Variovorax abundance in tumors as compared to non-tumor adjacent paired lung tissue (FDR corrected P=0.013). The species of Variovorax was identified histologically, and also by two additional 16S rRNA strategies (Resphera Insight analysis and PacBio sequencing). A group of taxa were associated with squamous cell carcinoma (SCC), of which Acidovorax were enriched in smokers (P =0.0013). Further, these taxa, including Acidovorax, exhibited higher abundance among the subset of SCC cases with TP53 mutations, an association not seen in adenocarcinomas (AD). Therefore, we observed a microbiome-gene and a microbiome-exposure interaction in SCC lung cancer tissue. Together, these results open the door for future biomarker research that could be used to improve screening and direct mechanistic studies of lung cancer therapy. Citation Format: Leigh Greathouse, James White, Valery Bliskovsky, Ashley Vargas, Eric Polley, Elise Bowman, Mohammed Khan, Ana Robles, Brid Ryan, Amiran Dzutsev, Giorgio Trinchieri, Marbin Pineda, Sven Bilke, Paul Meltzer, Marina Walther-Antonio, Garth Ehrlich, Joshua Mell, Joshua Earl, Sergey Balashov, Archana Bhat, Alex Valm, Clayton Deming, Sean Conlan, Julia Oh, Julie Segre, Curtis Harris. Microbiome-TP53 gene interaction in human lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4925. doi:10.1158/1538-7445.AM2017-4925

Abstract Children who are exposed to secondhand smoke (SHS) are faced with an increased risk of nicotine dependence later in life. We have previously shown that children exposed to SHS have an increased risk of lung cancer as adults. Furthermore, genetic variation plays a role in the susceptibility of individuals to lung cancer. The gene DRD1 mediates dopamine signaling following nicotine exposure, thus we reasoned that DRD1 may be related to lung cancer via modulation of the nicotine reward pathway. Our previous studies identified 4 SNPs (rs4809294, rs2292975, rs4861327, rs686) that were predicted to modulate a microRNA binding site and we assessed the association of these SNPs with lung cancer risk. Our current study investigated whether these SNPs were associated with nicotine dependence and whether this had a subsequent effect on lung cancer risk. We used the National Cancer Institute-Maryland lung cancer case-control study. Cases and controls were recruited from the greater Baltimore metropolitan area. We used ordinal logistic regression to examine the association between SNPs and nicotine dependence. Logistic regression adjusted for age, gender and smoking was used to assess the association between SNPs and lung cancer risk. No significant associations were found between genotypes in the 4 SNPs and nicotine dependence levels (n=1,450). Individuals with the heterozygous allele (AG) exposed to SHS during childhood had increased odds of lung cancer compared to those with the homozygous wild type allele (AA) for rs686 (OR=1.52, CI= 1.12, 2.07). Individuals with the homozygous variant allele (GG) exposed to childhood SHS had increased odds of lung cancer compared to individuals with the homozygous wild type allele (AA) (OR=2.11, CI= 1.45, 3.10). Individuals with the heterozygous allele (GA) and the highest levels of nicotine dependence who were also exposed to childhood SHS, had higher odds of lung cancer than those with the homozygous recessive allele (AA) (OR=3.50, CI=1.37, 8.96). Consistent with earlier findings, heterozygotes (AG) had increased odds of lung cancer but this was not statistically significant (OR=1.90, CI= 0.82, 4.40). To further explore this association, we examined the effect of race on this relationship. Caucasians with the heterozygous allele (AG), the highest levels of nicotine dependence and childhood SHS, had increased odds of lung cancer compared to those with the homozygous recessive allele (AA) for rs686 (OR=1.47, CI=1.06, 2.05). Caucasians with the homozygous allele (GG) who were exposed to childhood SHS, had higher odds of lung cancer compared to individuals with the homozygous recessive allele (AA) for rs686 (OR=1.84, CI=1.15, 2.98). No association was found among African Americans. Although none of the SNPs examined were found to be associated with nicotine dependence, it appears that variations in rs686 may modify an individual's susceptibility to lung cancer due to SHS exposure. Citation Format: Victoria A. Zigmont, Brid M. Ryan, Jin Jen, Ana I. Robles, Cain McClary, Kara Calhoun, Elise D. Bowman, Kirsi Vähäkangas, K. Leigh Greathouse, Wang Yi, Angela S. Wenzlaff, Bo Deng, Ping Yang, Ann G. Schwartz, Curtis C. Harris, Susan Olivo Marston. Childhood exposure to secondhand smoke, nicotine dependence, and DRD1 are associated with lung cancer risk. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2156. doi:10.1158/1538-7445.AM2014-2156

Abstract Lung cancer has a familial component which suggests a genetic contribution to its etiology. Given the strong evidence linking smoking with lung cancer, we studied miRNA-related loci in genes associated with smoking behavior. CHRNA, CHRNB gene families, CYP2A6, and DRD1 (dopamine receptor D1) were mined for SNPs that fell within the seed region of miRNA binding sites and then tested for associations with risk in a three-stage validation approach. A 3′UTR (untranslated region) SNP in DRD1 was associated with a lower risk of lung cancer among individuals exposed to secondhand smoke during childhood [OR, 0.69; 95% confidence interval (CI), 0.60–0.79; P &lt; 0.0001]. This relationship was evident in both ever (OR, 0.74; 95% CI, 0.62–0.88; P = 0.001) and never smokers (OR, 0.61; 95% CI, 0.47–0.79; P &lt; 0.0001), European American (OR, 0.65; 95% CI, 0.53–0.80; P &lt; 0.0001), and African American (OR, 0.73; 95% CI, 0.62–0.88; P = 0.001) populations. Although much remains undefined about the long-term risks associated with exposure to secondhand smoke and heterogeneity between individuals in regard to their susceptibility to the effects of secondhand smoke, our data show an interaction between an SNP in the 3′UTR of DRD1 and exposure to secondhand smoke during childhood. Further work is needed to explore the mechanistic underpinnings of this SNP and the nature of the interaction between DRD1 and exposure to secondhand smoke during childhood. Cancer Prev Res; 7(12); 1210–8. ©2014 AACR.

Abstract In searching for a role for genetic variation in susceptibility to lung cancer, we postulated that miRNA modulating SNPs within smoking behavior associated genes, such as the nicotinic acetylcholine and dopamine receptor families, could modulate susceptibility to tobacco carcinogens and lung cancer risk. Bioinformatic analyses of these gene families identified 5 SNPs predicted to modulate a miRNA binding site. We assessed these SNPs in the National Cancer Institute-MD case-control study (European American [EA] & African Americans [AA] n=1,438). rs686 in DRD1 (dopamine receptor D1) was associated with a reduced risk of lung cancer after adjustment for age, gender and race (OR 0.63, 95% C.I. 0.47-0.85; P=0.002). As DRD1 mediates dopamine signaling following nicotine exposure, we reasoned that the rs686 variant associates with lung cancer risk via modulation of the nicotine reward pathway. However, adjustment for smoking both in terms of smoking status and pack-years did not significantly modulate the association (OR 0.57, 95% C.I. 0.40-0.81, P=0002). In addition, age at smoking initiation, pack-years of smoking and levels of urinary nicotine metabolites (cotinine and hydroxycotinine) did not vary across rs686 genotypes. Moreover, in an analysis of a never smoking cohort from Mayo Clinic, rs686 was also associated with a reduced risk of lung cancer (OR 0.77, 95% C.I. 0.62-0.97; P=0.027; n=629) (pooled analysis OR 0.61, 95% C.I. 0.47-0.78; P&lt;0.0001; n=2,067). Intriguingly, the association between rs686 and lung cancer risk was only observed in subjects exposed to tobacco smoke during childhood (EA smokers: [OR 0.63, 95% C.I. 0.45-0.88; P=0.007] EA never smokers [OR 0.64, 95% C.I. 0.49-0.85; P=0.002] AA smokers OR 0.31, 95% C.I. 0.11-0.89; P=0.029) (model adjusted as above and for education, adult-second-hand smoke exposure). To further explore a relationship between tobacco and DRD1, we exposed lung cancer cell lines to increasing doses of nicotine and observed a significant increase in DRD1 expression (P=0.009). As DRD1 lies within a CpG island, we are currently testing if this regulation occurs via epigenetic modulation of the DRD1 promoter. While a direct role for DRD1 in lung cancer has not previously been reported, a recent report linked DRD to the cancer stem cell hypothesis. Indeed, our work demonstrates that DRD1 is significantly upregulated in lung cells with cancer stem-like properties. Furthermore, miR-296, predicted to bind to variant rs686 allele, is increased in paired lung cancer tissues (P=0.0003), thus linking a decrease in DRD1 with reduced lung cancer risk. Collectively, our work suggests a novel lung cancer pathway whereby rs686 in DRD1 counteracts the increase in DRD1 imposed by exposure to tobacco smoke in both current and never smokers. Furthermore, it hints at a novel role for the dopamine receptor/signaling pathway in lung carcinogenesis. Citation Format: Brid M. Ryan, Ana I. Robles, Andrew C. McClary, Elise Bowman, Kirsi Vahakangas, Susan Olivo-Marston, Ping Yang, Jin Jen, Curtis C. Harris. Interaction between DRD1 and childhood exposure to environmental tobacco smoke modulates lung cancer risk in smokers and never smokers. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4581. doi:10.1158/1538-7445.AM2013-4581

Abstract Background: The EML4-ALK fusion gene is more frequently found in younger, never smoking patients with lung cancer. Meanwhile, never smokers exposed to secondhand tobacco smoke (SHS) during childhood are diagnosed at a younger age compared with never smoking patients with lung cancer who are not exposed. We, therefore, hypothesized that SHS, which can induce DNA damage, is associated with the EML4-ALK fusion gene. Methods: We compared the frequency of the EML4-ALK fusion gene among 197 never smoker patients with lung cancer with and without a history of exposure to SHS during childhood at Mayo Clinic. Results: The EML4-ALK fusion gene was detected in 33% of cases from never smokers with a history of SHS exposure during childhood, whereas 47% of never smoking lung cancer cases without a history of childhood SHS exposure tested positive for the fusion gene. Conclusions: The EML4-ALK fusion gene is not enriched in tumors from individuals exposed to SHS during childhood. Impact: These data suggest that childhood exposure to SHS is not a significant etiologic cause of the EML4-ALK fusion gene in lung cancer. Cancer Epidemiol Biomarkers Prev; 23(7); 1432–4. ©2014 AACR.