Intensive Weight Loss Intervention and Cancer Risk in Adults with Type 2 Diabetes: Analysis of the Look AHEAD Randomized Clinical Trial

OBJECTIVE

This study was designed to determine whether intensive lifestyle intervention (ILI) aimed at weight loss lowers cancer incidence and mortality.

METHODS

Data from the Look AHEAD trial were examined to investigate whether participants randomized to ILI designed for weight loss would have reduced overall cancer incidence, obesity-related cancer incidence, and cancer mortality, as compared with the diabetes support and education (DSE) comparison group. This analysis included 4,859 participants without a cancer diagnosis at baseline except for nonmelanoma skin cancer.

RESULTS

After a median follow-up of 11 years, 684 participants (332 in ILI and 352 in DSE) were diagnosed with cancer. The incidence rates of obesity-related cancers were 6.1 and 7.3 per 1,000 person-years in ILI and DSE, respectively, with a hazard ratio (HR) of 0.84 (95% CI: 0.68-1.04). There was no significant difference between the two groups in total cancer incidence (HR, 0.93; 95% CI: 0.80-1.08), incidence of nonobesity-related cancers (HR, 1.02; 95% CI: 0.83-1.27), or total cancer mortality (HR, 0.92; 95% CI: 0.68-1.25).

CONCLUSIONS

An ILI aimed at weight loss lowered incidence of obesity-related cancers by 16% in adults with overweight or obesity and type 2 diabetes. The study sample size likely lacked power to determine effect sizes of this magnitude and smaller.

Supporting Peer Learning Networks for Case-Based Learning in Public Health: Experience of the Rocky Mountain Public Health Training Center With the ECHO Training Model

Extension for Community Healthcare Outcomes (ECHO) is a model for professional training and support now being used widely in clinical health care. ECHO provides training for health care professionals in their own communities by creating peer learning groups connected by live bidirectional video communications. Topic experts lead the sessions, but most of the learning occurs through case presentations and consultations. Although similar to telemedicine, ECHO differs in that the responsibility for patient care remains with the primary care learners. The Rocky Mountain Public Health Training Center—which supports training for the public health workforce in the six-state region of Colorado, Utah, Wyoming, Montana, and North and South Dakota—has adapted the ECHO health care model for public health training, using the ECHO learning principles of creating and supporting peer learning networks connected by live bidirectional video, and employing a case-based learning approach. The public health ECHO trainings are facilitated by subject matter experts, focus on real-life public health challenges, and use programs or scenarios within communities as “cases.” This article looks at early success in using the ECHO model for public health training on topics such as local public health agency quality improvement, patient navigation, food safety, tobacco control, obesity prevention, tuberculosis management, and HIV prevention. The Rocky Mountain Public Health Training Center continues to refine its implementation of the ECHO learning model across a wide range of public health and population health topics and shows great promise as a framework for regional public health training.

The Interaction between Genetic Ancestry and Breast Cancer Risk Factors among Hispanic Women: The Breast Cancer Health Disparities Study

Background: Hispanic women have lower breast cancer incidence rates than non-Hispanic white (NHW) women. To what extent genetic versus nongenetic factors account for this difference is unknown.Methods: Using logistic regression, we evaluated the interactive influences of established risk factors and ethnicity (self-identified and identified by ancestral informative markers) on breast cancer risk among 2,326 Hispanic and 1,854 NHW postmenopausal women from the United States and Mexico in the Breast Cancer Health Disparities Study.Results: The inverse association between the percentage of Native American (NA) ancestry and breast cancer risk was only slightly attenuated after adjusting for known risk factors [lowest versus highest quartile: odds ratio (OR) =1.39, 95% confidence interval (CI) = 1.00-1.92 among U.S. Hispanics; OR = 1.92 (95% CI, 1.29-2.86) among Mexican women]. The prevalence of several risk factors, as well as the associations with certain factors and breast cancer risk, differed according to genetic admixture. For example, higher body mass index (BMI) was associated with reduced risk among women with lower NA ancestry only [BMI <25 versus >30: OR = 0.65 (95% CI, 0.44-0.98) among U.S. Hispanics; OR = 0.53 (95% CI, 0.29-0.97) among Mexicans]. The average number of risk factors among cases was inversely related to the percentage of NA ancestry.Conclusions: The lower NA ancestry groups were more likely to have the established risk factors, with the exception of BMI. Although the majority of factors were associated with risk in the expected directions among all women, BMI had an inverse association among Hispanics with lower NA ancestry.Impact: These data suggest that the established risk factors are less relevant for breast cancer development among women with more NA ancestry. Cancer Epidemiol Biomarkers Prev; 26(5); 692-701. ©2016 AACR.

The American Cancer Society challenge goal to reduce US cancer mortality by 50% between 1990 and 2015: Results and reflections

In 1996, the Board of Directors of the American Cancer Society (ACS) challenged the United States to reduce what looked to be possible peak cancer mortality in 1990 by 50% by the year 2015. This analysis examines the trends in cancer mortality across this 25-year challenge period from 1990 to 2015. In 2015, cancer death rates were 26% lower than in 1990 (32% lower among men and 22% lower among women). The 50% reduction goal was more fully met for the cancer sites for which there was enactment of effective approaches for prevention, early detection, and/or treatment. Among men, mortality rates dropped for lung cancer by 45%, for colorectal cancer by 47%, and for prostate cancer by 53%. Among women, mortality rates dropped for lung cancer by 8%, for colorectal cancer by 44%, and for breast cancer by 39%. Declines in the death rates of all other cancer sites were substantially smaller (13% among men and 17% among women). The major factors that accounted for these favorable trends were progress in tobacco control and improvements in early detection and treatment. As we embark on new national cancer goals, this recent past experience should teach us that curing the cancer problem will require 2 sets of actions: making new discoveries in cancer therapeutics and more completely applying those discoveries in cancer prevention we have already made. CA Cancer J Clin 2016;66:359-369. © 2016 American Cancer Society.

Impact of a behavioral weight loss intervention on comorbidities in overweight and obese breast cancer survivors

PURPOSE

Comorbid medical conditions are common among breast cancer survivors, contribute to poorer long-term survival and increased overall mortality, and may be ameliorated by weight loss. This secondary analysis evaluated the impact of a weight loss intervention on comorbid medical conditions immediately following an intervention (12 months) and 1-year postintervention (24 months) using data from the Exercise and Nutrition to Enhance Recovery and Good health for You (ENERGY) trial-a phase III trial which was aimed at and successfully promoted weight loss.

METHODS

ENERGY randomized 692 overweight/obese women who had completed treatment for early stage breast cancer to either a 1-year group-based behavioral intervention designed to achieve and maintain weight loss or to a less intensive control intervention. Minimal support was provided postintervention. New medical conditions, medical conditions in which non-cancer medications were prescribed, hospitalizations, and emergency room visits, were compared at baseline, year 1, and year 2. Changes over time were analyzed using chi-squared tests, Kaplan-Meier, and logistic regression analyses.

RESULTS

At 12 months, women randomized to the intervention had fewer new medical conditions compared to the control group (19.6 vs. 32.2 %, p < 0.001); however, by 24 months, there was no longer a significant difference. No difference was observed in each of the four conditions for which non-cancer medications were prescribed, hospital visits, or emergency visits at either 12 or 24 months.

CONCLUSIONS

These results support a short-term benefit of modest weight loss on the likelihood of comorbid conditions; however, recidivism and weight regain likely explain no benefit at 1-year postintervention follow-up.

Changes in biomarkers and DNA methylation in breast cancer survivors enrolled in the ENERGY weight loss trial: A pilot study

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Background: In 2014, an ASPO position statement was released calling for action regarding cancer survivors’ needs for weight management. Reduction of body weight is hypothesized to affect several cancer-related biological pathways. Methods: The Exercise and Nutrition to Enhance Recovery and Good health for You (ENERGY) trial is the largest weight loss trial completed to date among breast cancer survivors. In it, 692 stage Ic-IIIc breast cancer survivors were randomized to an intensive, group-based weight loss intervention with 26 contacts over one year or to a non-intensive intervention with two contacts over the same time period. Results recently reported in JCO showed significantly greater weight loss in the intensive intervention arm compared to the non-intensive arm. A pilot study exploring baseline to 6-month changes in gene methylation and expressed biomarkers was undertaken in 30 chemo-naïve, post-menopausal, non-Hispanic white women who participated in this study. Results: Several significant differences in mean change scores (standard error) between the intensive vs. non-intensive groups were noted, i.e., insulin: -4.19(0.80) vs. 0.42 (1.01)/p = 0.0016; c-peptide: -0.49(0.14) vs. 0.40(0.19)/p = 0.0009; leptin: -15.73(1.79) vs. 2.53(1.78)/p < 0.0001; adiponectin:leptin ratio: 0.67(0.15) vs. 0.010(0.064)/p = 0.0007; homeostasis model of insulin resistance (HOMA-IR): 20.00(4.65) vs. 9.57(5.00)/p = 0.0003; sex hormone binding globulin 20.45(4.61) vs. 8.65(8.00)/p = 0.023; and Follistatin-Related Protein-3 (FSTL3): 0.48(0.19) vs. -0.88(0.55)/p = 0.0497. While effects were in the direction hypothesized for c-reactive protein, interleukin-6, vascular endothelial growth factor, and tumor necrosis factor no significant differences were noted. Significant differences in DNA methylation also were noted for genes encoding for Follistatin Related Protein (corresponds to FSTL3), and those on hormonal/growth pathways (e.g., AMOTL1, ESR, EGR3), inflammatory pathways (e.g., TNFRS10A/TRAIL-R1, C14orf106), and metabolic pathways (e.g., ZBED3, GABRA). Conclusions: While results are based on a small sample and not corrected for multiple testing, they provide evidence that weight loss affects several biomarkers and pathways that impact cancer and which warrant further investigation. Clinical trial information: NCT01112839.

Quality of life outcomes from the Exercise and Nutrition Enhance Recovery and Good Health for You (ENERGY)-randomized weight loss trial among breast cancer survivors

Obesity is a poor prognostic factor and is negatively related to quality of life (QOL) in breast cancer survivors. Exercise and Nutrition to Enhance Recovery and Good Health for You is the largest weight loss trial completed among cancer survivors. Percent losses in body weight with an intensive group-based intervention versus an attention control were 6.0 versus 1.5 % (p < 0.0001) and 3.7 versus 1.3 % (p < 0.0001) at 12 and 24 months, respectively. ENERGY also was designed to answer the research question: Does weight loss significantly improve vitality and physical function (key components of QOL)? 692 breast cancer survivors (BMI: 25-45 kg/m(2)) at 4 US sites were randomized to a year-long intensive intervention of 52 group sessions and telephone counseling contacts versus a non-intensive (control) of two in-person counseling sessions. Weight, self-reported QOL, and symptoms were measured semi-annually for two years. Significant decreases in physical function and increases in symptoms were observed among controls from baseline to 6 months, but not in the intervention arm, -3.45 (95 % Confidence Interval [CI] -6.10, -0.79, p = 0.0109) and 0.10 (95 %CI 0.04, 0.16, p = 0.0021), respectively. Improvements in vitality were seen in both arms but trended toward greater improvement in the intervention arm -2.72 (95 % CI -5.45, 0.01, p = 0.0508). These differences diminished over time; however, depressive symptoms increased in the intervention versus control arms and became significant at 24 months, -1.64 (95 % CI -3.13, -0.15, p = 0.0308). Increased QOL has been reported in shorter term diet and exercise trials among cancer survivors. These longer term data suggest that diet and exercise interventions improve some aspects of QOL, but these benefits may diminish over time.

Body fatness as a cause of cancer: epidemiologic clues to biologic mechanisms

Carrying excess body fat is a leading cause of cancer. Epidemiologic evidence gives strong clues about the mechanisms that link excess adiposity to risk for several cancer sites. For postmenopausal breast cancer and endometrial cancer, the hyper-estrogenic state that is induced by excess body fatness is the likely cause. For esophageal cancer and gallbladder cancer, chronic local inflammation induced by acid reflux and gallstones is the likely cause, and for liver cancer, local inflammation induced by hepatic fatty infiltration is the likely cause. However, for several other cancers known to be associated with excess adiposity, including cancers of the colon, pancreas, ovary, kidney, and prostate, specific causes are not known. Possible candidates include elevated systemic or local tissue inflammation induced by adiposity and effects of the elevated levels of leptin, insulin, IGFs, and depressed immune function that are seen with excess adiposity. There is growing evidence that intentional weight loss not only reduces circulating levels of cancer-associated factors but that it also reduces cancer incidence and recurrence. Better research is needed to understand the mechanisms that link excess body fat to cancer risk as well as to understand the amount of weight loss needed for substantial cancer risk reduction. Finally, as we develop better understanding of the mediators of the effects of excess body fatness on cancer risk, we should identify pharmacologic interventions that target those mediators so that they can be used to complement weight loss in order to reduce cancer risk.

Lack of significant association between serum inflammatory cytokine profiles and the presence of colorectal adenoma

Background

Inflammatory cytokines in the colonic microenvironment have been shown to increase with advance colorectal cancer disease state. However, the contribution of inflammatory cytokines to pre-malignant disease, such as the formation of adenomas, is unclear.

Methods

Using the Milliplex® MAP Human Cytokine/ Chemokine Magnetic Bead Panel Immunoassay, serum cytokine and chemokine profiles were assayed among participants without an adenoma (n = 97) and those with an adenoma (n = 97) enrolled in the NCI-funded Insulin Resistance Atherosclerosis Colon Study. The concentrations of interleukin-10 (IL-10), IL-1β, IL-6, IL-17A, IL-2, IL-4, IL-7, IL-12(p70), interferon-γ (IFN-γ), macrophage chemoattractant protein-1 (MCP-1), regulated on activation, normal T cell expressed and secreted (RANTES), tumor necrosis factor-alpha (TNF-α), vascular endothelial growth factor (VEGF), granulocyte macrophage colony-stimulating factor (GM-CSF), and macrophage inflammatory protein-1β (MIP-1β) were determined. Multiple logistic regression analyses were used to evaluate the association between adenoma prevalence and cytokine levels.

Results

The presence of colorectal adenomas was not associated with significant increases in the systemic levels of proinflammatory (TNF-α, IL-6, IL-1β) or T-cell polarizing (IL-12, IL-2, IL-10, IL-4, IL-17, IFN-γ) cytokines. Furthermore, MCP-1 and RANTES levels were equivalent in the serum of study participants with and without adenomas.

Conclusions

These findings suggest colorectal adenoma prevalence may not be associated with significant alterations in systemic inflammation.

Association between lifetime exposure to inorganic arsenic in drinking water and coronary heart disease in Colorado residents

BACKGROUND

Chronic diseases, including coronary heart disease (CHD), have been associated with ingestion of drinking water with high levels of inorganic arsenic (> 1,000 μg/L). However, associations have been inconclusive in populations with lower levels (< 100 μg/L) of inorganic arsenic exposure.

OBJECTIVES

We conducted a case-cohort study based on individual estimates of lifetime arsenic exposure to examine the relationship between chronic low-level arsenic exposure and risk of CHD.

METHODS

This study included 555 participants with 96 CHD events diagnosed between 1984 and 1998 for which individual lifetime arsenic exposure estimates were determined using data from structured interviews and secondary data sources to determine lifetime residence, which was linked to a geospatial model of arsenic concentrations in drinking water. These lifetime arsenic exposure estimates were correlated with historically collected urinary arsenic concentrations. A Cox proportional-hazards model with time-dependent CHD risk factors was used to assess the association between time-weighted average (TWA) lifetime exposure to low-level inorganic arsenic in drinking water and incident CHD.

RESULTS

We estimated a positive association between low-level inorganic arsenic exposure and CHD risk [hazard ratio (HR): = 1.38, 95% CI: 1.09, 1.78] per 15 μg/L while adjusting for age, sex, first-degree family history of CHD, and serum low-density lipoprotein levels. The risk of CHD increased monotonically with increasing TWAs for inorganic arsenic exposure in water relative to < 20 μg/L (HR = 1.2, 95% CI: 0.6, 2.2 for 20-30 μg/L; HR = 2.2; 95% CI: 1.2, 4.0 for 30-45 μg/L; and HR = 3, 95% CI: 1.1, 9.1 for 45-88 μg/L).

CONCLUSIONS

Lifetime exposure to low-level inorganic arsenic in drinking water was associated with increased risk for CHD in this population.

Weight gain prior to entry into a weight-loss intervention study among overweight and obese breast cancer survivors

PURPOSE

Changes in cancer therapy, in addition to changes in obesity prevalence, suggest the need for a current assessment of weight gain patterns following breast cancer diagnosis. The aim of this study was to evaluate factors associated with weight gain among breast cancer survivors prior to enrolling into a behavioral weight loss intervention.

METHODS

Anthropometric measures and data on weight-related factors were collected at baseline on 665 breast cancer survivors. Postdiagnosis weight gain was determined between entry into the trial and previous diagnosis up to 5 years. Multivariate logistic regression analyses were used to evaluate the association between weight gain and influencing factors.

RESULTS

The mean weight gain was 4.5 % body weight (standard deviation = 10.6); 44 % of women experienced ≥5 % body weight gain. The risk of weight gain was inversely associated with age (adjusted odds ratio (ORadj) = 0.97, 95 % confidence interval (95 % CI) 0.95-0.99), Hispanic ethnicity (ORadj = 0.30, 95 % CI 0.13-0.68), and overweight (ORadj = 0.11, 95 % CI 0.05-0.23) or obese (ORadj = 0.03, 95 % CI 0.02-0.07) status at diagnosis and positively associated with time elapsed since diagnosis (ORadj = 1.19/year, 95 % CI 1.04-1.36). Women prescribed aromatase inhibitors were 46 % less likely to gain weight compared to women prescribed selective estrogen-receptor modulators (ORadj = 0.54, 95 % CI 0.31-0.93). The risk of weight gain was positively associated with smoking at diagnosis (ORadj = 2.69, 95 % CI 1.12-6.49) although this was attributable to women who subsequently quit smoking.

CONCLUSIONS

Postdiagnosis weight gain is common and complex and influenced by age, ethnicity, weight, smoking status, time elapsed since diagnosis, and endocrine-modulating therapy.

IMPLICATIONS FOR CANCER SURVIVORS

Weight gain continues to be a concern following a diagnosis of breast cancer. Factors influencing this weight gain include age, ethnicity, weight, smoking status, time elapsed since diagnosis, and endocrine-modulating therapy. Effective weight management strategies are needed for this population of women.

Predicting arsenic concentrations in groundwater of San Luis Valley, Colorado: implications for individual-level lifetime exposure assessment

Consumption of inorganic arsenic in drinking water at high levels has been associated with chronic diseases. Risk is less clear at lower levels of arsenic, in part due to difficulties in estimating exposure. Herein we characterize spatial and temporal variability of arsenic concentrations and develop models for predicting aquifer arsenic concentrations in the San Luis Valley, Colorado, an area of moderately elevated arsenic in groundwater. This study included historical water samples with total arsenic concentrations from 595 unique well locations. A longitudinal analysis established temporal stability in arsenic levels in individual wells. The mean arsenic levels for a random sample of 535 wells were incorporated into five kriging models to predict groundwater arsenic concentrations at any point in time. A separate validation dataset (n = 60 wells) was used to identify the model with strongest predictability. Findings indicate that arsenic concentrations are temporally stable (r = 0.88; 95 % CI 0.83-0.92 for samples collected from the same well 15-25 years apart) and the spatial model created using ordinary kriging best predicted arsenic concentrations (ρ = 0.72 between predicted and observed validation data). These findings illustrate the value of geostatistical modeling of arsenic and suggest the San Luis Valley is a good region for conducting epidemiologic studies of groundwater metals because of the ability to accurately predict variation in groundwater arsenic concentrations.

Physical activity and gastric cancer: so what? An epidemiologist's confession

Epidemiologists, like many scientists, tend to become specialized and focused on a particular disease, even though behavioral risk factors such as physical activity have effects across many diseases. This commentary is a personal reflection by an epidemiologist on the shortcomings of this disease-oriented approach to prevention.

Long-term weight gain among Hispanic and non-Hispanic White women with and without breast cancer

Weight gain following breast cancer diagnosis is common, but limited data exists on whether this gain is in excess of that gained during normal aging. This study investigated weight patterns among women with and without breast cancer to determine the effects of the breast cancer experience on weight change. Using the SHINE 4-Corners Breast Cancer Study, 305 women with breast cancer and 345 women without were followed prospectively. Weight change of ≥5% was defined as the difference between the self-reported weight measurements obtained at breast cancer diagnosis (or referent date for women without breast cancer) and about 6 yr later. Multiple logistic regression analyses were used. Within this cohort, 60% of women were overweight or obese and 37% of women gained weight. No significant greater weight gain was observed between women with vs. without breast cancer [adjusted odds ratio (ORadj) = 1.15, 95% CI 0.79-1.68] or between Hispanic vs. non-Hispanic White women (ORadj = 1.09, 95% CI 0.72-1.66) after adjustment. Weight gain was associated with being younger and having a lower body mass index. Among breast cancer survivors, cancer treatment factors were not associated with weight gain. These results suggest that weight management approaches are needed, especially those targeted to at-risk populations such as breast cancer survivors.

Dietary intake of folate, B-vitamins and methionine and breast cancer risk among Hispanic and non-Hispanic white women

Background

Low dietary folate intake is associated with several neoplasias, but reports are inconsistent for breast cancer. Additionally, the association of folate with breast cancer estrogen receptor (ER) status is not well established.

Objective

To determine if dietary intakes of folate, B-vitamins (B₂, B₆, B₁₂) and methionine are associated with breast cancer risk and ER status in Hispanic, and non-Hispanic White women in the southwestern US.

Materials and Methods

Primary breast cancer cases (n = 2,325) in the 4-Corners region (Arizona, Colorado, New Mexico and Utah), diagnosed between October 1999 and May 2004, were identified through state cancer registries. Controls (n = 2,525) were frequency-matched by ethnicity and age (±5 years). Dietary intake, physical activity and other exposures were assessed using in-person interviews. Risk was assessed through multivariable and multinomial logistic regression with adjustment for relevant covariates.

Result

While there was no overall association with breast cancer, the highest quartile of folate intake was marginally inversely associated with ER− breast cancer (Odds Ratio (OR) = 0.50, 95%CI 0.25–1.00, p for trend = 0.07). Vitamin B₁₂ intake was inversely associated with breast cancer also (OR = 0.73, 95%CI 0.53–1.00, p for trend = 0.06), particularly for the highest quartile of ER+ breast cancer (OR = 0.67, 95%CI 0.46–0.99, p for trend = 0.06), among NHW women (OR = 0.49, 95%CI 0.29–0.81, p for trend = 0.01) and invasive breast cancer (OR = 0.63; 95%CI: 0.42, 0.93, P_trend = 0.01). Methionine intake was also inversely associated with ER+ breast cancer (OR for 4^th quartile = 0.83, 95%CI 0.66–1.03, p for trend = 0.04), primarily among Hispanic women (OR = 0.71, 95%CI 0.47–1.06, and P for trend = 0.02).

Conclusion

Higher intake of folate is marginally associated with a lower risk for ER− breast cancer, and higher intakes of vitamin B-12 and methionine are marginally associated with a lower risk of ER+ breast cancer.

Nutrition and physical activity guidelines for cancer survivors

Cancer survivors are often highly motivated to seek information about food choices, physical activity, and dietary supplements to improve their treatment outcomes, quality of life, and overall survival. To address these concerns, the American Cancer Society (ACS) convened a group of experts in nutrition, physical activity, and cancer survivorship to evaluate the scientific evidence and best clinical practices related to optimal nutrition and physical activity after the diagnosis of cancer. This report summarizes their findings and is intended to present health care providers with the best possible information with which to help cancer survivors and their families make informed choices related to nutrition and physical activity. The report discusses nutrition and physical activity guidelines during the continuum of cancer care, briefly highlighting important issues during cancer treatment and for patients with advanced cancer, but focusing largely on the needs of the population of individuals who are disease free or who have stable disease following their recovery from treatment. It also discusses select nutrition and physical activity issues such as body weight, food choices, food safety, and dietary supplements; issues related to selected cancer sites; and common questions about diet, physical activity, and cancer survivorship.

Defining a gene promoter methylation signature in sputum for lung cancer risk assessment

PURPOSE

To evaluate the methylation state of 31 genes in sputum as biomarkers in an expanded nested, case-control study from the Colorado cohort, and to assess the replication of results from the most promising genes in an independent case-control study of asymptomatic patients with stage I lung cancer from New Mexico.

EXPERIMENTAL DESIGN

Cases and controls from Colorado and New Mexico were interrogated for methylation of up to 31 genes using nested, methylation-specific PCR. Individual genes and methylation indices were used to assess the association between methylation and lung cancer with logistic regression modeling.

RESULTS

Seventeen genes with ORs of 1.4 to 3.6 were identified and selected for replication in the New Mexico study. Overall, the direction of effects seen in New Mexico was similar to Colorado with the largest increase in case discrimination (ORs, 3.2-4.2) seen for the PAX5α, GATA5, and SULF2 genes. Receiver operating characteristic (ROC) curves generated from seven-gene panels from Colorado and New Mexico studies showed prediction accuracy of 71% and 77%, respectively. A 22-fold increase in lung cancer risk was seen for a subset of New Mexico cases with five or more genes methylated. Sequence variants associated with lung cancer did not improve the accuracy of this gene methylation panel.

CONCLUSIONS

These studies have identified and replicated a panel of methylated genes whose integration with other promising biomarkers could initially identify the highest risk smokers for computed tomographic screening for early detection of lung cancer.

Benefits and harms of CT screening for lung cancer: a systematic review

CONTEXT

Lung cancer is the leading cause of cancer death. Most patients are diagnosed with advanced disease, resulting in a very low 5-year survival. Screening may reduce the risk of death from lung cancer.

OBJECTIVE

To conduct a systematic review of the evidence regarding the benefits and harms of lung cancer screening using low-dose computed tomography (LDCT). A multisociety collaborative initiative (involving the American Cancer Society, American College of Chest Physicians, American Society of Clinical Oncology, and National Comprehensive Cancer Network) was undertaken to create the foundation for development of an evidence-based clinical guideline.

DATA SOURCES

MEDLINE (Ovid: January 1996 to April 2012), EMBASE (Ovid: January 1996 to April 2012), and the Cochrane Library (April 2012).

STUDY SELECTION

Of 591 citations identified and reviewed, 8 randomized trials and 13 cohort studies of LDCT screening met criteria for inclusion. Primary outcomes were lung cancer mortality and all-cause mortality, and secondary outcomes included nodule detection, invasive procedures, follow-up tests, and smoking cessation.

DATA EXTRACTION

Critical appraisal using predefined criteria was conducted on individual studies and the overall body of evidence. Differences in data extracted by reviewers were adjudicated by consensus.

RESULTS

Three randomized studies provided evidence on the effect of LDCT screening on lung cancer mortality, of which the National Lung Screening Trial was the most informative, demonstrating that among 53,454 participants enrolled, screening resulted in significantly fewer lung cancer deaths (356 vs 443 deaths; lung cancer−specific mortality, 274 vs 309 events per 100,000 person-years for LDCT and control groups, respectively; relative risk, 0.80; 95% CI, 0.73-0.93; absolute risk reduction, 0.33%; P = .004). The other 2 smaller studies showed no such benefit. In terms of potential harms of LDCT screening, across all trials and cohorts, approximately 20% of individuals in each round of screening had positive results requiring some degree of follow-up, while approximately 1% had lung cancer. There was marked heterogeneity in this finding and in the frequency of follow-up investigations, biopsies, and percentage of surgical procedures performed in patients with benign lesions. Major complications in those with benign conditions were rare.

CONCLUSION

Low-dose computed tomography screening may benefit individuals at an increased risk for lung cancer, but uncertainty exists about the potential harms of screening and the generalizability of results.

Sex-specific association of sequence variants in CBS and MTRR with risk for promoter hypermethylation in the lung epithelium of smokers

Gene promoter hypermethylation is now regarded as a promising biomarker for the risk and progression of lung cancer. The one-carbon metabolism pathway is postulated to affect deoxyribonucleic acid (DNA) methylation because it is responsible for the generation of S-adenosylmethionine (SAM), the methyl donor for cellular methylation reactions. This study investigated the association of single nucleotide polymorphisms (SNPs) in six one-carbon metabolism-related genes with promoter hypermethylation in sputum DNA from non-Hispanic white smokers in the Lovelace Smokers Cohort (LSC) (n = 907). Logistic regression was used to assess the association of SNPs with hypermethylation using a high/low methylation cutoff. SNPs in the cystathionine beta synthase (CBS) and 5-methyltetrahydrofolate-homocysteine methyltransferase reductase (MTRR) genes were significantly associated with high methylation in males [CBS rs2850146 (-8283G > C), OR = 4.9; 95% CI: 1.98, 12.2, P = 0.0006] and low methylation in females [MTRR rs3776467 (7068A > G), OR = 0.57, 95% CI: 0.42, 0.77, P = 0.0003]. The variant allele of rs2850146 was associated with reduced gene expression and increased plasma homocysteine (Hcy) concentrations. Three plasma metabolites, Hcy, methionine and dimethylglycine, were associated with increased risk for gene methylation. These studies suggest that SNPs in CBS and MTRR have sex-specific associations with aberrant methylation in the lung epithelium of smokers that could be mediated by the affected one-carbon metabolism and transsulfuration in the cells.

Dietary supplements and cancer prevention: balancing potential benefits against proven harms

Nutritional supplementation is now a multibillion-dollar industry, and about half of all US adults take supplements. Supplement use is fueled in part by the belief that nutritional supplements can ward off chronic disease, including cancer, although several expert committees and organizations have concluded that there is little to no scientific evidence that supplements reduce cancer risk. To the contrary, there is now evidence that high doses of some supplements increase cancer risk. Despite this evidence, marketing claims by the supplement industry continue to imply anticancer benefits. Insufficient government regulation of the marketing of dietary supplement products may continue to result in unsound advice to consumers. Both the scientific community and government regulators need to provide clear guidance to the public about the use of dietary supplements to lower cancer risk.

Abstract 2633: Single nucleotide polymorphisms in one carbon metabolism genes are associated with methylation patterns and plasma metabolites in high risk smokers based on gender

Lung cancer is the leading cause of cancer related deaths and most lung cancers are detected at a late stage. Gene promoter hypermethylation is now regarded as a promising biomarker to identify early risk and progression of lung cancer. The one carbon metabolism pathway is postulated to affect DNA methylation because it is necessary for the generation of S-adenosyl methionine or (SAM), the methyl donor for cellular DNA methylation reactions, through complex interactions with metabolites including folate, homocysteine, and methionine. This study investigated the association of single nucleotide polymorphisms (SNPs) in one carbon metabolism related genes with DNA promoter hypermethylation in sputum cell DNA from current and former smokers in the Lovelace Smokers Cohort (n=907). The association of SNPs with methylation was analyzed by logistic regression using gender specific high and low methylation cutoffs from a 12 gene methylation panel as the outcome. SNPs in the cystathionine beta-synthase (CBS) and 5-methyltetrahydrofolate-homocysteine methyltransferase reductase (MTRR) genes were found to be statistically associated with methylation in a gender specific fashion (CBS SNP, OR=4.9; CI: 1.98, 12.2, p=.0006 in males) and (MTRR SNP, OR= 0.57, CI: 0.42, 0.77, p=0.0003 in females). Plasma homocysteine levels and the ratio of homocysteine to cystathionine increased in male samples with heterozygous or homozygous minor alleles of the CBS SNP compared to male samples with homozygous common alleles (n=86). This study suggests that SNPs in the CBS and MTRR genes are associated with methylation patterns in smokers by gender. The CBS SNP may be important in regulating plasma homocysteine and cystathionine levels that could theoretically mediate the aberrant DNA methylation in smokers at high risk to develop lung cancer. Grant Support: This work is supported by K01CA128823 NCI (Flores) and R01CA097356 NCI (Belinsky).

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 2633. doi:1538-7445.AM2012-2633

New American Cancer Society process for creating trustworthy cancer screening guidelines

Guidelines for cancer screening written by different organizations often differ, even when they are based on the same evidence. Those dissimilarities can create confusion among health care professionals, the general public, and policy makers. The Institute of Medicine (IOM) recently released 2 reports to establish new standards for developing more trustworthy clinical practice guidelines and conducting systematic evidence reviews that serve as their basis. Because the American Cancer Society (ACS) is an important source of guidance about cancer screening for both health care practitioners and the general public, it has revised its methods to create a more transparent, consistent, and rigorous process for developing and communicating guidelines. The new ACS methods align with the IOM principles for trustworthy clinical guideline development by creating a single generalist group for writing the guidelines, commissioning independent systematic evidence reviews, and clearly articulating the benefits, limitations, and harms associated with a screening test. This new process should ensure that ACS cancer screening guidelines will continue to be a trustworthy source of information for both health care practitioners and the general public to guide clinical practice, personal choice, and public policy about cancer screening.

Does intentional weight loss reduce cancer risk?

Epidemiologic evidence points to obesity as a major risk factor for many cancers, including cancers of the breast, endometrium, colorectum, kidney, oesophagus and pancreas. Whether intentional weight loss might reduce this excess risk is not yet proven. We searched the medical literature for studies reporting changes in cancer risk following intentional weight loss, and for studies reporting changes in cancer-relevant risk factors of oestrogens, sex hormone binding globulin (SHBG), Insulin-like growth factor-I (IGF-I), IGF binding proteins and selected inflammatory markers [C-reactive protein (CRP), interleukin 6 (IL-6) and tumour necrosis factor-α (TNF-α)]. Observational cohort studies and randomized controlled trials of both dietary interventions and bariatric surgery all indicate fairly immediate reductions in cancer incidence following intentional weight loss. Oestrogen levels drop and SHBG levels increase coincident with intentional weight loss, with about a one-third reduction in free oestradiol to be expected from a 10% weight loss. CRP levels also drop substantially after weight loss at about this same 3 : 1 ratio. Reductions in TNF-α and IL-6 are consistently seen, but of a smaller magnitude, and IGF-I and IGFBP changes after weight loss are small and inconsistent. Because both cancer incidence and levels of circulating cancer biomarkers drop fairly rapidly following weight loss, intentional weight loss may well lead to meaningful reductions in cancer risk with a short latency time.

Examining stools for colon cancer prevention: what are we really looking for?

Fecal immunochemical testing (FIT) is superior to guiac-based testing if we are looking for blood in stools, as it has better one-time colorectal cancer sensitivity and specificity and better patient acceptance. In this issue of the journal, Cai and colleagues (beginning on page 1572) and Khalid-de Bakker and colleagues (beginning on page 1563) present new information about the one-time test performance of FIT. FIT will have a growing appeal to providers and health care systems as resources for clinical preventive services shrink and as incentives to expand colorectal screening rates increase, but there are good reasons to be cautious about the temptation to organize new FIT screening programs. Colorectal screening has two potential objectives: To find cancers in an earlier, more-treatable stage and to find and remove adenomas to prevent cancers from forming in the first place. Because most adenomas, even advanced adenomas, do not bleed, tests designed to identify occult blood in the stool are better for detecting colorectal cancer, whereas direct endoscopic visualization of the colorectum is better for prevention. Even if advanced adenomas did commonly bleed, low compliance with repeat annual testing will seriously erode the benefit of FIT.

Estimating the global and regional burden of suboptimal nutrition on chronic disease: methods and inputs to the analysis

BACKGROUND/OBJECTIVES

Global burdens of cardiovascular disease (CVD), diabetes and cancer are on the rise. Little quantitative data are available on the global impact of diet on these conditions. The objective of this study was to develop systematic and comparable methods to quantitatively assess the impact of suboptimal dietary habits on CVD, diabetes and cancer burdens globally and in 21 world regions.

SUBJECTS/METHODS

Using a comparative risk assessment framework, we developed methods to establish for selected dietary risk factors the effect sizes of probable or convincing causal diet-disease relationships, the alternative minimum-risk exposure distributions and the exposure distributions. These inputs, together with disease-specific mortality rates, allow computation of the numbers of events attributable to each dietary factor.

RESULTS

Using World Health Organization and similar evidence criteria for convincing/probable causal effects, we identified 14 potential diet-disease relationships. Effect sizes and ranges of uncertainty will be derived from systematic reviews and meta-analyses of trials or high-quality observational studies. Alternative minimum-risk distributions were identified based on amounts corresponding to the lowest disease rates in populations. Optimal and alternative definitions for each exposure were established based on the data used to quantify harmful or protective effects. We developed methods for identifying and obtaining data from nationally representative surveys. A ranking scale was developed to assess survey quality and validity of dietary assessment methods. Multi-level hierarchical models will be developed to impute missing data.

CONCLUSIONS

These new methods will allow, for the first time, assessment of the global impact of specific dietary factors on chronic disease mortality. Such global assessment is not only possible but is also imperative for priority setting and policy making.

Increase in circulating levels of IGF-1 and IGF-1/IGFBP-3 molar ratio over a decade is associated with colorectal adenomatous polyps

High levels of circulating insulin-like growth factor-1 (IGF-1) have been associated with increased risk of several cancers. Regarding colorectal cancer, these associations are generally weak. We hypothesized that an increase in IGF-1 over time would be a stronger risk factor for cancer-related outcomes than the actual levels. In this analysis we utilized existing data from the Insulin Resistance and Atherosclerosis Study (IRAS). Circulating IGF-1 levels and molar ratios of IGF-1 to IGF binding protein 3 (IGFBP-3) were measured at three time points, within a 10-year follow-up period. We examined the associations of increase of the two variables with the presence of colorectal adenoma at the end of follow-up among participants with normal glucose tolerance at baseline. This included 143 individuals, from which 24 were diagnosed with adenomatous polyps. Although the mean levels of IGF-1 and IGF-1/IGFBP-3 decline with age, ~ 30% of the participants showed an increase of at least fifteen percent ("ever increase") in one or both of these variables, compared to baseline. We found a positive association between "ever increase" in IGF-1 or IGF-1/IGFBP-3 and the presence of colorectal adenoma: ORs were 3.81 (95% CI: 1.30-10.8) and 2.83 (95% CI: 1.00-8.22), respectively. No association was found when analyzing the actual levels of both variables at any time point. Our data suggest that an increase in circulating IGF-1 or IGF-1/IGFBP-3 may represent a disturbed GH/IGF1 homeostasis, which could favor the development of precancerous lesions such as colorectal adenoma.

Abstract B62: Beta-2 adrenergic receptor polymorphisms and risk of breast cancer among Hispanic and non-Hispanic white women: The 4-Corners Breast Cancer Study

Polymorphisms in the adrenergic receptor beta-2 (ADRB2) gene have been studied in relation to risk of type 2 diabetes and obesity, but few studies have investigated associations with breast cancer. The purpose of this research was to evaluate the hypothesis that ADRB2 variants (rs1042713-Arg16Gly and rs1042714-Glu27Gln) are associated with breast cancer risk in non-Hispanic white (NHW) and Hispanic (H) women using data from a population-based case-control study conducted in the southwestern United States: ‘The 4-Corners Breast Cancer Study’. A total of 1,244 NHW and 606 H cases with incident primary breast were ascertained and 1,330 NHW and 728 H population-based controls were selected. Information on lifestyle and physical activity, diet, demographics, and reproductive background was collected through an in-person questionnaire, and blood samples were taken for genetic analyses from consenting participants. ADRB2 genotypes for rs1042713 and rs1042714 were determined using PCR. Each genotype as well as their combined haplotype was evaluated in multivariable logistic regression models to estimate the associations with breast cancer risk while adjusting for potential confounders, including study center, history of diabetes, body mass index, family history of breast cancer, genetic admixture, and menopausal status. ADRB2 genotype frequencies were significantly different between NHW and H women. Individually, the ADRB2 polymorphisms were not associated with breast cancer in either ethnic group. However, having 2 copies compared to one or zero copies of the ADRB2 G-G haplotype was associated significantly with increased risk of breast cancer among NHW women [odds ratio (OR), 1.95; 95% confidence interval (95% CI), 1.26–3.01] but reduced risk among Hispanic women [OR, 0.74; 95% CI, 0.50–1.09], (p-for interaction=0.004). Risk was significantly decreased in Hispanic women with a history of type 2 diabetes and 2 copies of the G-G haplotype [OR, 0.33; 95% CI, 0.12–0.92] while the association was increased, but not statistically significant among NHW women, [OR, 4.91; 95% CI, 0.52–46.60], (p-for interaction = 0.025). While the interaction between obesity (body mass index (BMI) ≥ 30 kg/m2) and the G-G haplotype was not significant (p=0.200), the association in NHW obese women with 2 copies of the G-G haplotype was similarly increased [OR, 3.01; 95% CI, 1.22–7.44], but decreased in Hispanics [OR, 0.42; 95% CI, 0.20–0.56]. These data suggest that ethnicity modifies the association between the ADRB2 G-G haplotype and breast cancer risk and history of type 2 diabetes and obesity enhances the divergence of risk between Hispanic and NHW women.

Citation Information: Cancer Epidemiol Biomarkers Prev 2011;20(10 Suppl):B62.

Differential expression of prognostic biomarkers between interval and screen-detected breast cancers: does age or family history matter?

The aim of this study was to compare tumor expression of prognostic biomarkers between interval breast cancers and screen-detected breast cancers overall, and according to age at diagnosis and familial risk. Tissue micro-arrays were constructed from 98 breast cancers (47 interval and 51 screen-detected) diagnosed in women in the Cancer Genetics Network. Arrays were immuno-stained to compare protein expression of six biomarkers including estrogen and progesterone receptor (ER/PR), Her2/neu, EGFR, cytokeratin 5/6, and Ki67. Fisher's Exact test was used to compare expression between interval and screen-detected cancers. Interval cancers were larger (P = 0.04), higher stage (P < 0.001), and more likely to have lobular histology (P = 0.01) than screen-detected cancers. Overall, interval cancers more often overexpressed EGFR (P = 0.01) and were somewhat more likely to be ER- (55% vs. 43%, P = 0.3), and triple negative (ER-/PR-/Her2-) (21 vs. 12%, P = 0.26). A greater difference in the proportion of interval versus screen-detected tumors that were ER- (53 vs. 35%; P = 0.29), PR- (35 vs. 21%; P = 0.25) and EGFR+ (17 vs. 0%; P = 0.02) was evident among women over 50. There was a trend toward differential expression among women with familial risk for PR- (P = 0.005) and triple negative status (P = 0.02). This study provides new data indicating that EGFR may be important in the etiology of interval cancer and be a possible therapeutic target. Our data also suggest that biological differences between interval and screen-detected cancers are more defined in older women. Future studies to confirm this finding and to elucidate novel markers for characterizing interval cancers may be more beneficial to this subgroup.

Ethnic disparities in breast tumor phenotypic subtypes in Hispanic and non-Hispanic white women

AIMS

Hispanic women are at a lower risk of getting breast cancer than non-Hispanic white (NHW) women, yet they experience a higher risk of mortality after diagnosis. There is some evidence to suggest differences in tumor pathology; however, very limited research has been published on Hispanic women. This represents one of the first studies to evaluate the prevalence of tumor markers and phenotypic subtypes that are associated with poorer prognosis (human epidermal growth factor receptor 2 [HER2], triple negative and basal-like tumors) among Hispanic women.

METHODS

We reviewed pathology reports, obtained paraffin blocks of breast cancer tissue, and established tissue microarrays from NHW (n=119) and Hispanic women (n=69) who were Colorado participants in the 4-Corners Breast Cancer Study. We evaluated ethnic differences in the prevalence of tumor markers and phenotypic subtypes and assessed the contribution of risk factors in explaining the observed differences.

RESULTS

Consistent with other studies, Hispanic women had a higher prevalence of estrogen receptor-negative tumors compared with NHWs (36.2% vs. 22.7%, p=0.05). Hispanics also had an unexpectedly higher proportion of HER2-positive tumors compared with NHWs (31.9% vs. 14.3%, p<0.01). Independent of other prognostic factors, Hispanics were 2.8 times more likely to have a HER2-positive tumor (95% confidence interval [CI] 0.98-7.86). Hispanics were less likely to have the more favorable luminal A subtype, but no significant differences were observed for the less favorable basal-like or triple negative subtypes. However, there were suggestive differences when considering menopausal status.

CONCLUSIONS

These findings provide evidence that breast cancers among Hispanic women comprise a distinct spectrum of tumor subtypes when compared with NHW women.

The influence of comorbidities on overall survival among older women diagnosed with breast cancer

BACKGROUND

Previous studies have shown that summary measures of comorbid conditions are associated with decreased overall survival in breast cancer patients. However, less is known about associations between specific comorbid conditions on the survival of breast cancer patients.

METHODS

The Surveillance, Epidemiology, and End Results-Medicare database was used to identify primary breast cancers diagnosed from 1992 to 2000 among women aged 66 years or older. Inpatient, outpatient, and physician visits within the Medicare system were searched to determine the presence of 13 comorbid conditions present at the time of diagnosis. Overall survival was estimated using age-specific Kaplan-Meier curves, and mortality was estimated using Cox proportional hazards models adjusted for age, race and/or ethnicity, tumor stage, cancer prognostic markers, and treatment. All statistical tests were two-sided.

RESULTS

The study population included 64,034 patients with breast cancer diagnosed at a median age of 75 years. None of the selected comorbid conditions were identified in 37,306 (58%) of the 64,034 patients in the study population. Each of the 13 comorbid conditions examined was associated with decreased overall survival and increased mortality (from prior myocardial infarction, adjusted hazard ratio [HR] of death = 1.11, 95% CI = 1.03 to 1.19, P = .006; to liver disease, adjusted HR of death = 2.32, 95% CI = 1.97 to 2.73, P < .001). When patients of age 66-74 years were stratified by stage and individual comorbidity status, patients with each comorbid condition and a stage I tumor had similar or poorer overall survival compared with patients who had no comorbid conditions and stage II tumors.

CONCLUSIONS

In a US population of older breast cancer patients, 13 individual comorbid conditions were associated with decreased overall survival and increased mortality.

Macronutrient composition influence on breast cancer risk in Hispanic and non-Hispanic white women: the 4-Corners Breast Cancer Study

The association of dietary macronutrient composition with risk of breast cancer is not well understood. We investigated the macronutrient composition of diet in the 4-Corners Breast Cancer Study. Logistic regression models were used for case-control comparisons adjusted for age, center, education, smoking, total activity, calories, dietary fiber, dietary calcium, height, parity, recent hormone exposure, reference year body mass index (BMI), and the interaction of BMI and recent hormone exposure. Breast cancer risk declined with increasing dietary fat and increased with carbohydrates similarly across ethnicity and menopausal status. Associations of carbohydrate (direct) and fat (inverse), particularly saturated and monounsaturated fat, with breast cancer were present among normal and overweight postmenopausal women and absent among obese postmenopausal women. No substantive differences were noted in the association of macronutrients with risk of breast cancer between non-Hispanic white and Hispanic women. Associations of the macronutrients carbohydrate and fat with breast cancer risk were attenuated among postmenopausal obese women.

Lack of association between insulin sensitivity and colorectal adenoma risk

Insulin resistance is thought to mediate the association between obesity and colorectal neoplasia, but no prior studies have assessed stimulated insulin sensitivity as a risk factor for colorectal neoplasia. This prospective study examined the association between insulin sensitivity measured directly using the frequently sampled intravenous glucose tolerance test (FSIGT) and later risk of colorectal adenomas. Among participants with a range of glucose tolerance levels enrolled in the Insulin Resistance Atherosclerosis Study, colonoscopies were conducted on 600 participants ages ≥50 yr, regardless of symptoms, about 10 yr after the first FSIGT and 5 yr after the second. Multiple logistic regression analyses were used. Within this cohort, diabetes was not associated with colorectal adenoma risk [∼10 yr prior to colonoscopy adjusted odds ratio (OR(adj)) 1.00; 95% confidence interval (CI), 0.62-1.62 or ∼5 yr prior to colonoscopy OR(adj) 0.96; 95% CI, 0.62-1.50]. Among non-diabetic participants, insulin sensitivity was not associated with colorectal adenoma risk at either prior study visit [lowest vs. highest insulin sensitivity, ∼10 yr prior to colonoscopy OR(adj) 0.93; 95% CI 0.50-1.71 and ∼5 yr prior to colonscopy OR(adj) 0.74; 95% CI, 0.38-1.46]. These results suggest that factors other than insulin sensitivity mediate the relationship between obesity and colorectal neoplasia.

Abstract 4637: Intra-individual changes in circulating IGF-1 and IGF-1/IGFBP-3 molar ratio are associated with colorectal adenomatous polyps presence

Background: High levels of circulating insulin-like growth factor-1 (IGF-1) have been associated with increased risks of several cancers, including colorectal cancer.

Methods: In a sub-cohort of the Insulin Resistance and Atherosclerosis Study (IRAS), we examined the associations between circulating IGF-1 and IGF-1/IGFBP-3 molar ratios, as well as their change patterns during 10-year follow-up, with the presence of colorectal adenomatous polyps at the end of the follow-up.

Results: The general trend was decrease of both variables with age. Based on this trend, two patterns were considered: “no increase” (variation within 15% of baseline and/or decrease) and “ever increase” (at least one increase of &gt; 15%). In the subgroup of participants with normal glucose tolerance, “ever increase” was positively associated with colorectal adenoma: ORs were 3.65 (1.30-10.8) and 2.83 (1.00-8.22) for IGF-1 and IGF-1/IGFBP-3, respectively. No association was found between actual levels of IGF-1 or IGF-1/IGFBP-3 at any time point and the presence of colorectal adenoma.

Conclusion: Our data suggest that increase in circulating IGF-1 and IGF-1/IGFBP-3 may represent an unnatural trend of a disturbed signaling pathway, which could favor the development of precancerous lesions, such as colorectal adenoma.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4637. doi:10.1158/1538-7445.AM2011-4637

Abstract 891: The association of single nucleotide polymorphisms in folate metabolism genes with hypermethylation patterns in smokers at high risk for lung cancer

Hypermethylation of promoter regions serve as potential biomarkers for the early detection of lung cancer. Because folate metabolism is necessary for nucleotide synthesis and DNA methylation reactions, that when perturbed, may both contribute to the development of cancer, hypermethylation of promoter regions in folate metabolism genes may be particularly important to explore. Dietary folate was recently found to protect against gene promoter hypermethylation patterns. This study investigated the association of functional and haplotype tagging single nucleotide polymorphisms (SNPs) in folate metabolism genes with promoter hypermethylation in sputum cell DNA from a cohort of current and former smokers (n=937). This cohort was a subset of the Lovelace Smokers’ Cohort of approximately 2000 high risk current and former smokers who were non-Hispanic white and for whom a complete methylation panel was obtained. Methylation panel status from a 12 gene panel was dichotomized into high and low methylation based on a cutoff of the number of genes methylated (&gt; = 3 genes for women and &gt; = 4 genes for men were categorized as high). Lymphocyte DNA was interrogated on a 96 SNP Illumina Goldengate platform. A SNP in the cystathionine-beta synthase gene (CBS), that converts homocysteine to cystathionine, was found to be significantly associated with gene promoter hypermethylation. Analyses used logistic regression and adjusted for multiple comparisons. There was an interaction between gender and CBS (p&lt;0.0001), so we conducted a stratified analysis by gender. Males with the variant allele had an increased risk of methylation (OR = 3.61; 95% CI: 1.71, 7.64); p&lt;0.001) and females with the variant allele had a decreased risk for methylation (OR = 0.64; 95% CI: 0.40, 1.00; p=0.05). A 20% reduction in CBS gene transcription was seen in bronchial epithelial cells heterozygous for the CBS variant allele compared to cells without the variant allele but was not statistically significant. Epidemiological studies have shown that men have higher levels of homocysteine compared to women but the mechanisms regulating this difference are not known. This study shows that a SNP in the CBS gene is associated with methylation patterns in smokers at high risk to develop lung cancer and differs by gender. This work may further help to elucidate the differences in lung cancer risk by gender.

Grant Support: This work is supported by K01CA128823 NCI and R01CA097356 NCI

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 891. doi:10.1158/1538-7445.AM2011-891

Integrating the totality of food and nutrition evidence for public health decision making and communication

The interpretation and integration of epidemiological studies detecting weak associations (RR < 2) with data from other study designs (e.g., animal models and human intervention trials) is both challenging and vital for making science-based dietary recommendations in the nutrition and food safety communities. The 2008 ILSI North America “Decision-Making for Recommendations and Communication Based on Totality of Food-Related Research” workshop provided an overview of epidemiological methods, and case-study examples of how weak associations have been incorporated into decision making for nutritional recommendations. Based on the workshop presentations and dialogue among the participants, three clear strategies were provided for the use of weak associations in informing nutritional recommendations for optimal health. First, enable more effective integration of data from all sources through the use of genetic and nutritional biomarkers; second, minimize the risk of bias and confounding through the adoption of rigorous quality-control standards, greater emphasis on the replication of study results, and better integration of results from independent studies, perhaps using adaptive study designs and Bayesian meta-analysis methods; and third, emphasize more effective and truthful communication to the public about the evolving understanding of the often complex relationship between nutrition, lifestyle, and optimal health.

Comparative analysis of breast cancer risk factors among Hispanic and non-Hispanic white women

BACKGROUND

Hispanic and non-Hispanic white (NHW) populations within the United States have different breast cancer incidence rates, yet there is limited research on how ethnic differences in the prevalence of established risk factors and their associations with breast cancer contribute to the observed differences.

METHODS

Odds ratios and population-attributable risk estimates for breast cancer were determined for Hispanic and NHW women in the population-based, case-control 4-Corners Breast Cancer Study.

RESULTS

When comparing NHW and Hispanic women, the authors observed differences in the prevalence of certain risk factors and in the magnitude and direction of their associations with breast cancer. Hispanic women were more likely to have characteristics associated with lower breast cancer risk, such as younger age at first birth, having more children, shorter height, less hormone use, and less alcohol consumption. Among premenopausal women, ethnic differences in risk were observed with taller height and positive family history, which were not associated with breast cancer among Hispanic women. Among postmenopausal women, associations for certain risk factors were either weaker or were not observed in Hispanics, such as recent estrogen plus progestin hormone therapy use and younger age at menarche. Among NHW women, an estimated 62% to 75% of breast cancers were attributed to the evaluated risk factors compared with 7% to 36% in Hispanic women.

CONCLUSIONS

Breast cancer risk factors established in NHW populations had less influence on breast cancer risk in Hispanic women. These findings reflect the need to further evaluate breast cancer risk factors among different ethnic and racial populations.

Population-based estimate of the contribution of TP53 mutations to subgroups of early-onset breast cancer: Australian Breast Cancer Family Study

Although germline TP53 mutations have been identified in women with breast cancer from families meeting Li-Fraumeni criteria, their contribution to breast cancer per se is not well known, but is thought to be minimal. We aimed to determine the prevalence of germline TP53 mutations in subgroups of early-onset breast cancer. Germline TP53 mutation status was assessed by DNA sequencing, screening for heterozygous single-nucleotide polymorphisms, and Multiplex Ligation-Dependent Probe Amplification analyses. From an Australian population-based series of invasive breast cancers, we studied (a) 52 women diagnosed before age 30 years unselected for family history [very early-onset (VEO)] and (b) 42 women diagnosed in their 30s with two or more first- or second-degree relatives with breast or ovarian cancer [early-onset family history (EO-FH)]. Of the VEO group, two (4%) had a mutation: G13203A (exon 6 missense) in a 24-year-old and a large 5,338-bp genomic deletion in a 26-year-old. Neither had a family cancer history that met Li-Fraumeni criteria. Of the EO-FH group, three (7%) had a mutation: T13240G (a known intron 5 splicing mutation) in a 36-year-old from a classic Li-Fraumeni family; G12299A (exon 4 missense) in a 33-year-old from a Li-Fraumeni-like family; and 14058delG (exon 7 frame-shift) in a 39-year-old with a family cancer history that did not meet Li-Fraumeni criteria. Germline TP53 mutations play a larger role in early-onset breast cancer than previously thought, and in this context, can be evident outside clinically defined Li-Fraumeni families.