Limburg, Paul J.

Alcohol consumption is associated with a modest increased risk of colon cancer, but its relationship with colon cancer survival has not been elucidated. Using data from a phase III randomized adjuvant trial, we assessed the association of alcohol consumption with colon cancer outcomes. Patients completed a risk factor questionnaire before randomization to FOLFOX or FOLFOX + cetuximab (N = 1984). Information was collected on lifestyle factors, including smoking, physical activity and consumption of different types of alcohol. Cox models assessed the association between alcohol consumption and outcomes of disease‐free survival (DFS), time‐to‐recurrence (TTR) and overall survival (OS), adjusting for age, sex, study arm, body mass, smoking, physical activity and performance status. No statistically significant difference in outcomes between ever and never drinkers were noted [hazard ratio (HR)DFS = 0.86, HRTTR = 0.87, HROS = 0.86, p‐values = 0.11–0.17]. However, when considering alcohol type, ever consumers of red wine (n = 628) had significantly better outcomes than never consumers (HRDFS = 0.80, HRTTR = 0.81, HROS = 0.78, p‐values = 0.01–0.02). Favorable outcomes were confirmed in patients who consumed 1‐30 glasses/month of red wine (n = 601, HR = 0.80–0.83, p‐values = 0.03–0.049); there was a suggestion of more favorable outcomes in patients who consumed >30 glasses/month of red wine (n = 27, HR = 0.33–0.38, p‐values = 0.05–0.06). Beer and liquor consumption were not associated with outcomes. Although alcohol consumption was not associated with colon cancer outcomes overall, mild to moderate red wine consumption was suggestively associated with longer OS, DFS and TTR in stage III colon cancer patients.

Abstract Background Although a number of cancer chemopreventive agents have now been evaluated in phase II and phase III clinical trials that assess their efficacy and tolerability in both high risk and general populations, few have shown clear efficacy and uptake of approved agents has been disappointingly low. Therefore, chemopreventive agents should undergo rigorous screening prior to clinical trial evaluation in order to improve the selection of suitable agents for testing in large, expensive multi-center phase III trials. The aim of this study is to develop a descriptive method for prioritizing candidate agents for further development. Methods This framework was developed through a systematic literature review of Pubmed/Medline, Embase and The Cochrane Library. A semi-quantitative assessment focusing on efficacy and toxicity/tolerability was established based on expert input. Data from clinical trials, cancer epidemiological, observational and preclinical studies, including in vivo and in vitro basic research, was used to retrospectively evaluate the clinical application and effectiveness of cancer chemopreventive agents. Two chemopreventive agents with either a positive (aromatase inhibitors (AIs) for breast cancer) or negative (selenium for lung cancer) phase III clinical trial outcome were subsequently evaluated to determine the usefulness of the framework. Results Chemopreventive agents must reduce or reverse the process of carcinogenesis in normal or pre-malignant tissue with minimal toxicity. Evaluation of efficacy included data from preclinical and animal models, epidemiological studies, and clinical trials (both early phase trials in the organ of interest as well as secondary endpoints from other relevant studies). Agent suitability evaluation included assessment of toxicities, tolerability, and agent specific attributes (PK/PD, bioavailability, dosing, etc.). Examination of selenium and AI historical data in these categories revealed strong concordance with phase III outcomes. The detailed descriptive evaluation of the agents will be presented. Conclusion This framework provides a descriptive paradigm for cancer chemopreventive agent evaluation through systematic and rigorous interrogation. Thorough, standardized evaluation of all available preclinical, epidemiological, and clinical data should be strongly encouraged to better inform the investments required for clinical trials. Citation Format: Naomi Walsh, David S. Alberts, Powel Brown, Paul Limburg, Mark Sherman, Eva Szabo. Framework for clinical evaluation of chemopreventive agents: Defining criteria for future assessment. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4662. doi:10.1158/1538-7445.AM2015-4662

Abstract Background: Microsatellite instability (MSI) and BRAF mutation status are associated with colorectal cancer survival, whereas the role of body mass index (BMI) is less clear. We evaluated the association between BMI and colorectal cancer survival, overall and by strata of MSI, BRAF mutation, sex, and other factors. Methods: This study included 5,615 men and women diagnosed with invasive colorectal cancer who were followed for mortality (maximum: 14.7 years; mean: 5.9 years). Prediagnosis BMI was derived from self-reported weight approximately one year before diagnosis and height. Tumor MSI and BRAF mutation status were available for 4,131 and 4,414 persons, respectively. Multivariable hazard ratios (HR) and 95% confidence intervals (CI) were estimated from delayed-entry Cox proportional hazards models. Results: In multivariable models, high prediagnosis BMI was associated with higher risk of all-cause mortality in both sexes (per 5-kg/m2; HR, 1.10; 95% CI, 1.06–1.15), with similar associations stratified by sex (Pinteraction: 0.41), colon versus rectum (Pinteraction: 0.86), MSI status (Pinteraction: 0.84), and BRAF mutation status (Pinteraction: 0.28). In joint models, with MS-stable/MSI-low and normal BMI as the reference group, risk of death was higher for MS-stable/MSI-low and obese BMI (HR, 1.32; P value: 0.0002), not statistically significantly lower for MSI-high and normal BMI (HR, 0.86; P value: 0.29), and approximately the same for MSI-high and obese BMI (HR, 1.00; P value: 0.98). Conclusions: High prediagnosis BMI was associated with increased mortality; this association was consistent across participant subgroups, including strata of tumor molecular phenotype. Impact: High BMI may attenuate the survival benefit otherwise observed with MSI-high tumors. Cancer Epidemiol Biomarkers Prev; 24(8); 1229–38. ©2015 AACR.

Abstract Background: Tumor features such as stage, grade, and microsatellite instability (MSI) status have relevance for colorectal cancer survival whereas the prognostic role of body mass index (BMI) is unclear. We assessed the association of BMI and adult weight gain on colorectal cancer survival, overall and by strata of sex and MSI. Methods: Participants were identified from a multi-center cohort that includes 6,763 colorectal cancer patients with invasive colorectal cancer who were enrolled into the Colon Cancer Family Registry from 1997 to 2008. Vital status was updated through direct contact with patients/next-of-kin and/or linkage with mortality records. BMI 2 years before diagnosis, BMI at age 20 years, and adult weight gain were derived from self-reports of height and weight (i.e., weight 2 years before diagnosis and weight at age 20 years). Tumor MSI status was available for 4,987 patients. Multivariable, two-sided hazard ratios (HR) and 95% confidence intervals (CIs) were estimated from delayed-entry Cox proportional hazards models, controlling for age at diagnosis, TNM summary stage (i.e., I, II, III, IV or missing), smoking (current, former, never), and study center. Results: After a maximum of 13.7 years of follow-up from enrollment to end-of-study (median: 5.3 years), 2,335 patients had died. Higher BMI 2 years before cancer diagnosis (per 5-kg/m2) was associated with higher risk of all-cause mortality overall (HR, 1.10; 95% CI, 1.05 to 1.14), with similar associations when stratified by sex (men: HR, 1.07; 95% CI, 1.02 to 1.14; women: HR, 1.11: 95% CI, 1.05 to 1.17; p-interaction: 0.18) and MSI status (MS-stable/MSI-low: HR, 1.08; 95% CI, 1.03 to 1.14; MSI-high, HR: 1.19; 95% CI, 1.02 to 1.40; p-interaction: 0.88). In joint models, with MS-stable/MSI-low and normal BMI as the referent group, risk of death was lower for those with MSI-high and normal BMI (HR: 0.77; 95% CI: 0.59 to 1.00), higher for MS-stable/MSI-low and high (≥30) BMI (HR: 1.23; 95% CI: 1.07 to 1.42), and essentially the same for MSI-high and high BMI (HR: 0.97; 95% CI: 0.72 to 1.30). Similar patterns of association were observed for BMI at age 20 years and when the outcome was colorectal cancer-specific mortality, although not all associations remained statistically significant for some of the smaller sub-group analyses. After controlling for BMI at age 20 years, adult weight gain was only modestly associated with all-cause mortality (per 5 kg HR: 1.01; 95% CI: 1.00 to 1.02; p-trend: 0.07). Conclusion: High pre-diagnosis BMI was associated with increased mortality after colorectal cancer diagnosis; this association was consistent for men and women and by tumor MSI status. These results also suggest that obesity attenuates the survival advantage observed with MSI-high tumors. Citation Format: Peter T. Campbell, Christina Newton, Polly A. Newcomb, Dennis Ahnen, John Baron, Sean Cleary, Michelle Cotterchio, A. Brad Farris, Jane Figueiredo, Roger C. Green, Loic Le Marchand, John McLaughlin, Amanda Phipps, John D. Potter, Andrew Renehan, Aung Ko Win, Noralane Lindor, Paul Limburg. Prospective study of body mass index and adult weight change with colorectal cancer survival, overall and by tumor microsatellite instability status. [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 LB-276. doi:10.1158/1538-7445.AM2014-LB-276

Abstract Background: Cigarette smoking (smoking), hormone therapy (MHT), and folate intake (folate) are each thought to influence colorectal cancer risk, but the underlying molecular mechanisms remain incompletely defined. Expression of estrogen receptor β (ESR2) has been associated with colorectal cancer stage and survival. Methods: In this prospective cohort study, we examined smoking, MHT, and folate-associated colorectal cancer risks by ESR2 protein expression level among participants in the Iowa Women's Health Study (IWHS). Self-reported exposure variables were assessed at baseline. Archived, paraffin-embedded colorectal cancer tissue specimens were collected and evaluated for ESR2 protein expression by IHC. Multivariate Cox regression models were fit to estimate relative risks (RR) and 95% confidence intervals (CI) for associations between smoking, MHT, or folate and ESR2-defined colorectal cancer subtypes. Results: Informative environmental exposure and protein expression data were available for 491 incident colorectal cancer cases. Positive associations between ESR2-low and -high tumors and several smoking-related variables were noted, most prominently with average number of cigarettes per day (RR, 4.24; 95% CI, 1.81–9.91 for ESR2-low and RR, 2.15; 95% CI, 1.05–4.41 for ESR2-high for ≥40 cigarettes compared with nonsmokers). For MHT, a statistically significant association with ESR2-low tumors was observed with longer duration of exposure (RR, 0.54; 95% CI, 0.26–1.13 for >5 years compared with never use). No associations were found for folate. Conclusions: In this study, smoking and MHT were associated with ESR2 expression patterns. Impact: These data support possible heterogeneous effects from smoking and MHT on ERβ-related pathways of colorectal carcinogenesis in older women. Cancer Epidemiol Biomarkers Prev; 24(4); 713–9. ©2015 AACR.

Abstract Background: Hormone therapy (HT) may prevent colorectal cancer (CRC), but the molecular mechanisms have not been fully defined. Expression of estrogen receptor beta (ERβ) has been associated with CRC stage and survival and may influence HT-related prevention pathways. In this prospective cohort study, we examined HT-associated CRC risk by ERβ protein expression levels in the population-based Iowa Women's Health Study (IWHS). Methods: The IWHS recruited 41,836 randomly selected Iowa women, ages 55-69 years, with a valid driver's license at study entry (1986). Exposure variables were assessed at baseline, by self-report. Incident CRC cases were ascertained by annual linkage with the Iowa Cancer Registry. Archived, paraffin-embedded tissue specimens were collected from 732 CRC cases, diagnosed through 12/31/2002, for molecular epidemiology studies. HT was categorized as never, former, and current and with durations of <=5 years or >5 years. ERβ protein expression was determined by immunohistochemistry on tissue microarrays. For each tumor core, both staining intensity (0-3) and proportion of cells stained (0-5) were scored. These two scores were added to determine negative (0), low (1-5) or high (6-8) ERβ protein expression levels. Multivariate Cox regression models were fit to estimate relative risks (RRs) and 95% confidence intervals (CIs). Results: Complete HT and ERβ data were available from 484 CRC cases. Associations between HT and CRC subtypes defined by ERβ expression level are shown in the Table. Conclusions: Data from the IWHS cohort suggest that current and longer-duration HT exposure favorably influence the risk for ERβ-neg or ERβ-low CRC cases to a greater degree than ERβ-high CRC cases. Further investigation is required to confirm these observations, and to clarify the underlying mechanisms. ERβ Neg or Low ERβ High Hormone Therapy Person years Events, N RR* (95% CI) Events, N RR* (95% CI) Never 341377 128 1.00 (Ref.) 196 1.00 (Ref.) Ever 212696 62 0.74 (0.54,1.03) 98 0.82 (0.63,1.07) Former 151535 48 0.79 (0.56,1.12) 67 0.73 (0.54,0.99) Current 61161 14 0.60 (0.33,1.09) 31 1.11 (0.74,1.64) P-trend 0.05 0.52 Duration < = 5yrs 148704 47 0.84 (0.59,1.19) 68 0.80 (0.60,1.08) >5yrs 60064 14 0.5 (0.26,0.93) 28 0.89 (0.59,1.34) P-trend 0.03 0.25 Citation Format: Lori S. Tillmans, Robert A. Vierkant, Alice H. Wang, Charles F. Lynch, Kristin E. Anderson, Amy J. French, Robert W. Haile, John D. Potter, Susan L. Slager, Thomas C. Smyrk, Stephen N. Thibodeau, James R. Cerhan, Paul J. Limburg. Hormone therapy and incident colorectal cancer risk by ER beta protein expression level in a population-based cohort of older women. [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 3652. doi:10.1158/1538-7445.AM2013-3652

Abstract Background: In patients with Barrett's esophagus, chronic reflux injury and inflammation are associated with esophageal adenocarcinoma, one of the most rapidly increasing lethal cancers. Epidemiological and preclinical studies support decreased risk of esophageal adenocarcinoma with NSAID use. Gastroesophageal refluxate contents can promote carcinogenesis in Barrett's metaplasia by activating AKT, which up regulates COX-2 expression and prostaglandin biosynthesis. We recently noted that neoplastic transformation in Barrett's esophagus is associated with increased AKT expression, particularly isoform AKT1. The AIM of this study is to investigate the effect of NSAID (Aspirin) use in patients with Barrett's esophagus on AKT1 expression using frozen tissue from the randomized, phase II trial of aspirin and esomeprazole for esophageal cancer chemoprevention in Barrett's esophagus patients and to assess the functional consequences of AKT1 expression in-vitro. Methods and Results: In a subset of patients (12 of 120 patients) with Barrett's esophagus who were randomized to placebo, lower dose (81 mg) or higher dose (325 mg) Aspirin for 4 weeks, both PCR and Western blot revealed marked reduction in AKT1 expression in patients who received 325 mg of Aspirin daily compared to patients who received placebo. Our in-vitro experiments support that AKT1 expression is functionally relevant to the process of carcinogenesis in Barrett's epithelial cells. Using adenovirus to induce AKT1 expression, we show that increased AKT1 expression increases Barrett's epithelial cell growth, facilitates RAS-mediated transformation of pre-neoplastic epithelial cells and promotes colony formation. Since AKT1 is known as Warburg kinase and regulates cellular glucose uptake to support aerobic glycolysis during growth de-regulation and neoplasia, we examined the uptake of fluorescent deoxyglucose analog (2-NBDG) in Barrett's epithelial cells transduced with AKT1 adenovirus. At 48 hrs, compared to control, AKT1 overexpression resulted in increased glucose uptake both by metaplastic and neoplastic Barrett's epithelial cells. Transcriptional repression of AKT1 abrogated the 2-NBDG uptake by these cells. Finally, we did pathway specific qPCRs and noted that use of Aspirin is associated with altered expression of chromatin remodelers that could down-regulate AKT1 expression. Conclusion: Collectively, our results demonstrate that Aspirin mediated down-regulation of Warburg kinase AKT1 in patients with Barrett?s esophagus is a novel mechanism for the regulation of Barrett?s epithelial cell growth. The in-depth characterization of molecular mechanisms is currently underway. This abstract is also presented as Poster A82. Citation Format: Navtej S. Buttar, Gary W. Falk, Cathrine J. DeMars, Sonia Chowdhury, Ahmed Elebiary, Anamay Sharma, Sidhartha Chaudhry, Nathan R. Foster, Katie L. Allen Ziegler, Yvonne Romero, Norman E. Marcon, Thomas Schnell, Douglas A. Corley, Prateek Sharma, Marcia R. Cruz-Correa, Chin Hur, David E. Fleischer, Amitabh Chak, Kenneth R. DeVault, David S. Weinberg, Gary Della’Zanna, Ellen Richmond, Thomas C. Smyrk, Sumithra Mandrekar, Paul J. Limburg. Aspirin mediated downregulation of Warburg kinase AKT1 in patients with Barrett's esophagus: Implications in neoplastic transformation. [abstract]. In: Proceedings of the Eleventh Annual AACR International Conference on Frontiers in Cancer Prevention Research; 2012 Oct 16-19; Anaheim, CA. Philadelphia (PA): AACR; Cancer Prev Res 2012;5(11 Suppl):Abstract nr PR-03.

Abstract Cigarette smoking (CS), hormone therapy (HT), and folate intake (FI) are each thought to influence colorectal cancer risk, but the underlying molecular mechanisms remain incompletely defined. The TP53 (p53) protein, encoded by the TP53 tumor-suppressor gene that is commonly mutated in colorectal cancer, can be readily assessed to differentiate biologically distinct colorectal cancer subtypes. In this prospective cohort study, we examined CS-, HT-, and FI-associated colorectal cancer risks by TP53 protein expression level among Iowa Women's Health Study (IWHS) participants. The IWHS recruited 41,836 randomly selected Iowa women, ages 55 to 69 years, with a valid driver's license at study entry in 1986. Self-reported exposure variables were assessed at baseline. Incident colorectal cancer cases were ascertained by annual linkage with the Iowa Cancer Registry. Archived, paraffin-embedded tissue specimens were collected and evaluated for TP53 protein expression by immunohistochemistry. Multivariate Cox regression models were fit to estimate relative risks (RR) and 95% confidence intervals (CI) for associations between CS, HT, or FI and TP53-defined colorectal cancer subtypes. Informative environmental exposure and protein expression data were available for 492 incident colorectal cancer cases: 222 (45.1%) TP53 negative, 72 (14.6%) TP53 low, and 198 (40.2%) TP53 high. Longer duration (>5 years) of HT was inversely associated with TP53 high colorectal cancers (RR, 0.50; 95% CI, 0.27–0.94). No other statistically significant associations were observed. These data support possible heterogeneous effects from HT on TP53-related pathways of colorectal carcinogenesis in older women. Cancer Epidemiol Biomarkers Prev; 23(2); 350–5. ©2013 AACR.