Weight change and risk of postmenopausal breast cancer (United States)

Utility of positron emission tomography for determination of axillary metastasis of breast cancer

Objectives

The involvement of axillary lymph nodes plays a key role in breast cancer staging. Positron emission tomography is a promising modality for detecting axillary lymph node metastasis. In addition, nomograms are used to predict the status of axillary lymph nodes. In this study, the role of positron emission tomography in determining axillary metastasis and its correlation with the nomogram was evaluated.

Material and Methods

The axillary maximum standard uptake value (SUVmax) values of the patients in the preoperative period, the features in the perioperative and postoperative specimen and Memorial Sloan Kettering Cancer Center nomogram data were evaluated.

Results

As axillary SUVmax detected by Positron emission tomography in the preoperative period increased, so did the likelihood of lymph node involvement. Axillary SUVmax value were compared with Memorial Sloan Kettering Cancer Center nomogram data but no correlation was found. Age, lymph node number, histopathology results, mass diameter, presence or absence of lymphovascular invasion and/or perineural invasion, tumor type, estrogen receptor status, Ki67 and Cerb-B2 statuses were not correlated. However, axillary SUVmax was inversely correlated with grade and progesterone receptor status.

Conclusion

Results from positron emission tomography of axillary lymph nodes in breasts cancer patients showed that SUVmax was only inversely related to cancer grade and progesterone receptor status while not correlating with other accepted parameters for tumor assessment. Thus there is insufficient reliability for the use of axillary SUVmax alone for accurate assessment of tumor characteristics at present.

Residual Risk of Breast Cancer After Bariatric Surgery

Importance

Excess adiposity confers higher risk of breast cancer for women. For women who have lost substantial weight, it is unclear whether previous obesity confers residual increased baseline risk of breast cancer compared with peers without obesity.

Objectives

To determine whether there is a residual risk of breast cancer due to prior obesity among patients who undergo bariatric surgery.

Design, Setting, and Participants

Retrospective matched cohort study of 69 260 women with index date between January 1, 2010, and December 31, 2016. Patients were followed up for 5 years after bariatric surgery or index date. Population-based clinical and administrative data from multiple databases in Ontario, Canada, were used to match a cohort of women who underwent bariatric surgery for obesity (baseline body mass index [BMI] ≥35 with comorbid conditions or BMI ≥40) to women without a history of bariatric surgery according to age and breast cancer screening history. Nonsurgical controls were divided into 4 BMI categories (<25, 25-29, 30-34, and ≥35). Data were analyzed on October 21, 2021.

Exposures

Weight loss via bariatric surgery.

Main Outcomes and Measures

Residual hazard of breast cancer after washout periods of 1, 2, and 5 years. Comparisons were made between the surgical and nonsurgical cohorts overall and within each of the BMI subgroups.

Results

In total, 69 260 women were included in the analysis, with 13 852 women in each of the 5 study cohorts. The mean (SD) age was 45.1 (10.9) years. In the postsurgical cohort vs the overall nonsurgical cohort (n = 55 408), there was an increased hazard for incident breast cancer in the nonsurgical group after washout periods of 1 year (hazard ratio [HR], 1.40 [95% CI, 1.18-1.67]), 2 years (HR, 1.31 [95% CI, 1.12-1.53]), and 5 years (HR, 1.38 [95% CI, 1.21-1.58]). When the postsurgical cohort was compared with the nonsurgical cohort with BMI less than 25, the hazard of incident breast cancer was not significantly different regardless of the washout period, whereas there was a reduced hazard for incident breast cancer among postsurgical patients compared with nonsurgical patients in all high BMI categories (BMI ≥25).

Conclusions and Relevance

Findings suggest that bariatric surgery was associated with a reduced risk of developing breast cancer for women with prior obesity equivalent to that of a woman with a BMI less than 25 and a lower risk when compared with all groups with BMI greater than or equal to 25.

Mouse Models of Obesity to Study the Tumor-Immune Microenvironment

Obesity is associated with chronic, low-grade systemic inflammation and leads to changes in the immune microenvironment of various tissues. As a result, obesity is associated with increased risk of cancer and a worse prognosis in patients. Given the prevalence of obesity worldwide, understanding the fundamental biology governing the relationship between obesity and cancer is critical. In this chapter, we describe preclinical models of obesity that can be combined with standard tumor models and techniques to study the tumor-immune microenvironment. We also discuss important considerations when planning experiments involving these models.

Impact on breast cancer susceptibility and clinicopathological traits of common genetic polymorphisms in TP53, MDM2 and ATM genes in Sardinian women

Common variants of genes involved in DNA damage correction [tumor protein p53 (TP53), murine double 2 homolog oncoprotein (MDM2) and ataxia-telengiectasia mutated (ATM)] may serve a role in cancer predisposition. The purpose of the present study was to investigate the association of five variants in these genes with breast cancer risk and clinicopathological traits in a cohort of 261 women from northern Sardinia. Polymorphic variants in TP53 (rs17878362, rs1042522 and rs1625895), MDM2 (rs2279744) and ATM (rs1799757) were determined by PCR and TaqMan single nucleotide polymorphism assay in patients with breast cancer (n=136) and healthy controls (n=125). Association with clinicopathological (e.g., age at diagnosis, lymph node involvement, clinical stage) and lifestyle factors (e.g., smoking status, alcohol intake, contraceptive use) was also evaluated. TP53 rs17878362 and rs1625895 polymorphisms were associated with decreased risk of BC diagnosis in patients older than 50 years (codominant and recessive models) and post-menopause (recessive model). Furthermore, there was a significant association between lymph node status (positive vs. negative) and ATM rs1799757-delT in dominant and additive models and between MDM2 rs2279744-allele and use of oral contraceptives. This analysis suggested that TP53 rs17878362 and rs1625895 may affect age of onset of breast cancer and ATM rs1799757 and MDM2 rs2279744 may be associated with lymph node status and prolonged use of oral contraceptives, respectively.

Obesity and Breast Cancer Risk: The Oncogenic Implications of Metabolic Dysregulation

CONTEXT

Breast cancer is increasing in prevalence in parallel with rising rates of obesity worldwide. Obesity is recognized as a leading modifiable risk factor for the development of breast cancer; however, this association varies considerably by clinicopathologic features, and the underlying mechanisms are complex.

EVIDENCE ACQUISITION

Pubmed literature search using combinations of "obesity," "breast cancer risk," "diet," "exercise," "weight gain," "weight loss," "adipose tissue inflammation," "crown-like structure," "immune markers," "metformin," "gliflozins," "SGLT-2i," "GLP1-RA," and related terms.

EVIDENCE SYNTHESIS

Elevated body mass index and weight gain are associated with increased risk of postmenopausal, hormone receptor-positive breast cancer. Emerging evidence suggests that adverse measures of body composition in individuals of any weight can also confer increased breast cancer risk. Mechanistically, various factors including altered adipokine balance, dysfunctional adipose tissue, dysregulated insulin signaling, and chronic inflammation contribute to tumorigenesis. Weight loss and more specifically fat mass loss through lifestyle and pharmacologic interventions improve serum metabolic and inflammatory markers, sex hormone levels, and measures of breast density, suggesting a link to decreased breast cancer risk.

CONCLUSION

Incorporating markers of metabolic health and body composition measures with body mass index can capture breast cancer risk more comprehensively. Further studies of interventions targeting body fat levels are needed to curb the growing prevalence of obesity-related cancer.

Environmental Enrichment Mitigates Age-Related Metabolic Decline and Lewis Lung Carcinoma Growth in Aged Female Mice

Aging is a complex physiological process that leads to the progressive decline of metabolic and immune function, among other biological mechanisms. As global life expectancy increases, it is important to understand determinants of healthy aging-including environmental and genetic factors-and thus slow the onset or progression of age-related disease. Environmental enrichment (EE) is a housing environment wherein laboratory animals engage with complex physical and social stimulation. EE is a prime model to understand environmental influences on aging dynamics, as it confers an antiobesity and anticancer phenotype that has been implicated in healthy aging and health span extension. Although EE is frequently used to study malignancies in young mice, fewer studies characterize EE-cancer outcomes in older mice. Here, we used young (3-month-old) and aged (14-month-old) female C57BL/6 mice to determine whether EE would be able to mitigate age-related deficiencies in metabolic function and thus alter Lewis lung carcinoma (LLC) growth. Overall, EE improved metabolic function, resulting in reduced fat mass, increased lean mass, and improved glycemic processing; many of these effects were stronger in the aged cohort than in the young cohort, indicating an age-driven effect on metabolic responses. In the aged-EE cohort, subcutaneously implanted LLC tumor growth was inhibited and tumors exhibited alterations in various markers of apoptosis, proliferation, angiogenesis, inflammation, and malignancy. These results validate EE as an anticancer model in aged mice and underscore the importance of understanding environmental influences on cancer malignancy in aged populations. PREVENTION RELEVANCE: Environmental enrichment (EE) serves as a model of complex physical and social stimulation. This study validates EE as an anticancer intervention paradigm in aged mice and underscores the importance of understanding environmental influences on cancer malignancy in aged populations.

Canine mammary cancer in overweight or obese female dogs is associated with intratumoral microvessel density and macrophage counts

Obesity is a major health condition owing to its effects on chronic diseases and cancers in humans, but little information is available regarding the role of obesity in canine mammary cancer (CMC). In the present study, we performed immunohistochemistry to investigate the effect of obesity on CMC by analyzing the number of tumor-associated macrophages, intratumoral microvessel density (iMVD), and the expression of prognostic factors including epidermal growth factor receptor (EGFR), cyclooxygenase 2 (COX-2), and Ki67 in CMC specimens. These data were compared in CMC specimens from lean or ideal body weight (Group 1) versus overweight or obese (Group 2) female dogs (n = 60 for each group). Associations between obesity status and histologic characteristics, such as histologic subtype, grading, and lymphatic invasion, were also investigated. Compared with lean or ideal body weight dogs, TAM (tumor-associated macrophage) counts (P < .005) and iMVD (P < .001) were significantly higher in overweight or obese dogs. CMC specimens of dogs in the overweight or obese group also showed higher histologic grade (P < .001). In addition, although no association was found between obesity status and either COX-2 or EGFR expression, Ki67 expression was greater in CMC specimens of overweight or obese dogs (P < .005). The results of this study suggest that obesity may influence CMC development and progression, being associated with higher histologic grade, greater infiltration of TAMs, and increased tumor angiogenesis.

The Relationship between Body Mass Index and Mammographic Density during a Premenopausal Weight Loss Intervention Study

We evaluated the association between short-term change in body mass index (BMI) and breast density during a 1 year weight-loss intervention (Manchester, UK). We included 65 premenopausal women (35-45 years, ≥7 kg adult weight gain, family history of breast cancer). BMI and breast density (semi-automated area-based, automated volume-based) were measured at baseline, 1 year, and 2 years after study entry (1 year post intervention). Cross-sectional (between-women) and short-term change (within-women) associations between BMI and breast density were measured using repeated-measures correlation coefficients and multivariable linear mixed models. BMI was positively correlated with dense volume between-women (r = 0.41, 95%CI: 0.17, 0.61), but less so within-women (r = 0.08, 95%CI: -0.16, 0.28). There was little association with dense area (between-women r = -0.12, 95%CI: -0.38, 0.16; within-women r = 0.01, 95%CI: -0.24, 0.25). BMI and breast fat were positively correlated (volume: between r = 0.77, 95%CI: 0.69, 0.84, within r = 0.58, 95%CI: 0.36, 0.75; area: between r = 0.74, 95%CI: 0.63, 0.82, within r = 0.45, 95%CI: 0.23, 0.63). Multivariable models reported similar associations. Exploratory analysis suggested associations between BMI gain from 20 years and density measures (standard deviation change per +5 kg/m² BMI: dense area: +0.61 (95%CI: 0.12, 1.09); fat volume: -0.31 (95%CI: -0.62, 0.00)). Short-term BMI change is likely to be positively associated with breast fat, but we found little association with dense tissue, although power was limited by small sample size.

Body weight variability and cancer incidence in men aged 40 years and older-Korean National Insurance Service Cohort

Repeated weight fluctuation has been proposed as a potential risk factor for increasing morbidity and mortality including cancer. We aimed to investigate the association between body weight variability (BWV) and all cancer and site-specific cancer incidence and the impact of smoking on these associations. A total of 1,759,848 cancer-free male subjects who had their weight measured at least 5 times from the National Health Insurance Service-Health Screening Cohort from 2002 to 2011 were included and followed up until 2015. BWV was defined as the average absolute difference between successive values (ASV). The risk of cancer and site-specific cancer from BWV was identified using Cox proportional hazards regression analysis using hazard ratios (HRs) and 95% confidence intervals (CIs) adjusted for potential confounders including weight, and stratified analysis was also conducted according to smoking status. During the 7,015,413 person-years of follow-up, 11,494 patients (0.65%) developed new-onset cancers. BWV was associated with a higher risk of all cancers after adjustment for confounders. The highest BWV quintile group compared to the lowest had greater risks of all cancers and site-specific cancers including lung, liver, and prostate cancer (HR 1.22, 95% CI 1.15–1.30; HR 1.22, 95% CI 1.07–1.39; HR 1.46, 95% CI 1.19–1.81; HR 1.36, 95% CI 1.15–1.62, in all cancers, lung, liver and prostate cancer, respectively). Due to small number of cancer occurrence, the risk of kidney cancer was increased, but statistically insignificant (HR 1.38, 95% CI 0.91–2.10). Similar results were observed in noncurrent smokers. However, in current smokers, the risks of all cancers and only prostate cancer were significantly increased in the highest BWV quintile group (HR 1.19, 95% CI 1.09–1.31; HR 1.51, 95% CI 1.08–2.11). The risk of kidney cancer also increased in this group, although the finding was not statistically significant (HR 1.77, 95% CI 0.87–3.63) This study suggested BWV is an independent risk factor for cancer in men, especially in lung, liver, and prostate cancer, but evidence was weaker in kidney cancer. This association remained significant only in prostate cancer in current smokers.

Association between weight cycling and risk of kidney cancer: a prospective cohort study and meta-analysis of observational studies

PURPOSE

Weight cycling is common in populations. However, it is unclear whether frequency and magnitude of weight cycling is associated with kidney cancer risk, independent of body mass index (BMI).

METHODS

A prospective cohort study followed 85,562 participants from Health Professionals Follow-up Study and Nurses' Health Study (1992-2014). At baseline, participants reported frequency and magnitude of intentional weight loss in the past 4 years. Cox proportional hazard model was used to estimate hazard ratios (HR) and 95% confidence intervals (CI). We also conducted a meta-analysis of all available observational studies including our two cohorts.

RESULTS

During 22 years of follow-up, we identified 441 kidney cancer cases. Compared with non-weight cyclers (no attempt of intentional weight loss), severe cyclers (≥ 3 times of intentional weight loss of ≥ 4.5 kg) were at increased kidney cancer risk after adjusting for BMI before weight cycling (pooled multivariable-adjusted HR, 1.78; 95% CI, 1.19, 2.66). Additional adjustment for attained BMI after weight cycling had minimal influence. There was a positive trend between weight cycling by frequency and magnitude and kidney cancer risk (P-trend = 0.01). Moreover, the observed positive association did not differ by subtypes of cyclers (e.g., adiposity status, weight-loss methods). In the meta-analysis, we found a strong positive association between weight cycling and kidney cancer risk (summary relative risk for weight cyclers vs. non-cyclers, 1.51; 95% CI, 1.16, 1.96; I²: 52.2%; 6 studies).

CONCLUSION

Frequent substantial weight cycling was associated with increased risk of kidney cancer, independent of BMI. Our study suggests that weight cycling may be an important risk factor for kidney cancer.

Dose-response effects of aerobic exercise on adiposity markers in postmenopausal women: pooled analyses from two randomized controlled trials

BACKGROUND/OBJECTIVE

Exercise may reduce the risk of breast cancer through adiposity changes, but the dose-response effects of exercise volume on adiposity markers are unknown in postmenopausal women. We aimed to compare the dose-response effects of prescribed aerobic exercise volume on adiposity outcomes.

PARTICIPANTS/METHODS

Data from the Alberta Physical Activity and Breast Cancer Prevention (ALPHA) and Breast Cancer and Exercise Trial in Alberta (BETA) were pooled for this analysis (N = 720). These were 12-month randomized controlled trials, where participants were randomized to 225 min/week (mid-volume) of aerobic exercise versus usual inactive lifestyle (ALPHA), or 150 min/week (low-volume) versus 300 min/week (high-volume) (BETA). Fat mass and fat-free mass were measured using DXA and intra-abdominal and subcutaneous fat area were assessed with computed tomography.

RESULTS

After 12 months of aerobic exercise, increasing exercise volumes from no exercise/control to 300 min/week resulted in statistically significant reductions in BMI, weight, fat mass, fat percentage, intra-abdominal and subcutaneous fat area (P < 0.001). Compared with controls, fat mass loss was -1.13, -1.98 and -2.09 kg in the low-, mid- and high-volume groups, respectively. Similarly, weight loss was -1.47, -1.83, -2.21 kg in the low-, mid- and high-volume groups, respectively, compared to controls, and intra-abdominal fat area loss was -7.44, -15.56 and -8.76 cm² in the low-, mid- and high-volume groups, respectively, compared to controls. No evidence for a dose-response effect on fat-free mass was noted.

CONCLUSION

A dose-response effect of exercise volume on adiposity markers was noted, however, the differences in adiposity markers were smaller when comparing 225 min/week to 300 min/week of exercise. Given the strong positive associations between obesity and postmenopausal breast cancer risk, this study provides evidence on the importance of exercise volume as part of the exercise prescription to reduce adiposity and, ultimately, postmenopausal breast cancer risk.

Weight Management and Physical Activity for Breast Cancer Prevention and Control

Observational evidence has consistently linked excess adiposity and inactivity to increased breast cancer risk and to poor outcomes in individuals diagnosed with early-stage, potentially curable breast cancer. There is less information from clinical trials testing the effect of weight management or physical activity interventions on breast cancer risk or outcomes, but a number of ongoing trials will test the impact of weight loss and other lifestyle changes after cancer diagnosis on the risk of breast cancer recurrence. Lifestyle changes have additional benefits beyond their potential to decrease primary or secondary breast cancer risk, including improvements in metabolic parameters, reduction in the risk of comorbidities such as diabetes and heart disease, improvement of physical functioning, and mitigation of side effects of cancer therapy. Despite these myriad benefits, implementation of lifestyle interventions in at-risk and survivor populations has been limited to date. This article reviews the evidence linking lifestyle factors to breast cancer risk and outcomes, discusses completed and ongoing randomized trials testing the impact of lifestyle change in primary and secondary breast cancer prevention, and reviews efforts to implement and disseminate lifestyle interventions in at-risk and breast cancer survivor populations.

Could ALDH2*2 be the reason for low incidence and mortality of ovarian cancer for East Asia women?

It is curious that East Asian women have a low incidence and mortality of ovarian cancer in various epidemiological studies. Although different explanations were given, they appear unsubstantial. We notice that East Asian population usually are inactive aldehyde dehydrogenase 2 mutation (ALDH2 ^* 2) carriers, and ALDH plays an important role in the resistance of ovarian cancer to chemotherapeutics, especially in ovarian cancer stem cells. Therefore, we hypothesize whether ALDH2 mutation is the major reason for low incidence and mortality of ovarian cancer in East Asian women, and use the evidence from literature, transcriptomic data with average 5-year overall survival to confirm our hypothesis.

Myocardial infarction, ischaemic stroke and pulmonary embolism before and after breast cancer hospitalisation

We studied the occurrence of myocardial infarction (MI), ischaemic stroke (IS) and pulmonary embolism (PE) before and after breast cancer hospitalisation compared with cancer-free controls. For this, women with a first breast cancer hospitalisation during 2000–2007 were selected from the PHARMO Record Linkage System, including drug use and hospitalisations of three million inhabitants in the Netherlands, and matched 1:10 by age to cancer-free women. The occurrence of MI, IS and PE were assessed in the 12 months before and after breast cancer hospitalisation. The study included 11,473 breast cancer patients, with a mean (± SD) age of 59 (± 14) years. Breast cancer patients were two to three times as likely as their cancer-free controls to have had a hospitalisation for PE, MI or IS in the 12 months before diagnosis, though prevalence was <1% in all groups. Breast cancer patients experienced an extreme high risk of PE in the first six months after diag- nosis (hazard ratio [HR] 23.5, 95% confidence interval [CI] 11.1–49.7 compared to controls), which declined gradually to a four times increased risk (HR 3.6, 95%CI 2.4–5.5) more than 12 months after breast cancer hospitalisation. However, incidence was low: less than five events per 1,000 person years during all time periods. For MI and IS we did not observe significant increased HRs after breast cancer hospitalisation compared to controls. Breast cancer patients seem to have a higher risk profile to develop MI and IS, and receive treatment that increases the risk of PE compared to cancer-free controls, although the frequency of hospitalisations was low.

Weight Fluctuation and Cancer Risk in Postmenopausal Women: The Women's Health Initiative

Background: Weight cycling, defined by an intentional weight loss and subsequent regain, commonly occurs in overweight and obese women and is associated with some negative health outcomes. We examined the role of various weight-change patterns during early to mid-adulthood and associated risk of highly prevalent, obesity-related cancers (breast, endometrial, and colorectal) in postmenopausal women.Methods: A total of 80,943 postmenopausal women (age, 63.4 ± 7.4 years) in the Women's Health Initiative Observational Study were categorized by self-reported weight change (weight stable; weight gain; lost weight; weight cycled [1-3, 4-6, 7-10, >10 times]) during early to mid-adulthood (18-50 years). Three site-specific associations were investigated using Cox proportional hazard models [age, race/ethnicity, income, education, smoking, alcohol, physical activity, hormone therapy, diet, and body mass index (BMI)].Results: A total of 7,464 (breast = 5,564; endometrial = 788; and colorectal = 1,290) incident cancer cases were identified between September 1994 and August 2014. Compared with weight stability, weight gain was significantly associated with risk of breast cancer [hazard ratio (HR), 1.11; 1.03-1.20] after adjustment for BMI. Similarly, weight cycling was significantly associated with risk of endometrial cancer (HR = 1.23; 1.01-1.49). Weight cycling "4 to 6 times" was most consistently associated with cancer risk, showing a 38% increased risk for endometrial cancer [95% confidence interval (CI), 1.08-1.76] compared with weight stable women.Conclusions: Weight gain and weight cycling were positively associated with risk of breast and endometrial cancer, respectively.Impact: These data suggest weight cycling and weight gain increase risk of prevalent cancers in postmenopausal women. Adopting ideal body-weight maintenance practices before and after weight loss should be encouraged to reduce risk of incident breast and endometrial cancers. Cancer Epidemiol Biomarkers Prev; 26(5); 779-86. ©2017 AACR.

Evaluation of a large healthy lifestyle program: informing program implementation and scale-up in the prevention of obesity

BACKGROUND

The Healthy Lifestyle Program for women (HeLP-her) is a low-intensity, self-management program which has demonstrated efficacy in preventing excess weight gain in women. However, little is known about the implementation, reach, and sustainability of low-intensity prevention programs in rural settings, where risk for obesity in women is higher than urban settings. We aimed to evaluate a low-intensity healthy lifestyle program delivered to women in a rural setting to inform development of effective community prevention programs.

METHODS

A mixed method hybrid implementation and evaluation study, guided by the RE-AIM framework (addressing the Reach, Effectiveness, Adoption, Implementation, and Maintenance), was undertaken. Data collection tools included anthropometric measures, program checklists, questionnaires, and semi-structured interviews with participants and local stakeholders. The RE-AIM self-audit tool was applied to assess evaluation rigor.

RESULTS

Six hundred and forty-nine women from 41 relatively socio-economic disadvantaged communities in Australia participated: mean age 39.6 years (±SD 6.7) and body mass index of 28.8 kg/m2 (±SD 6.9). A between-group weight difference of -0.92 kg (95% CI -1.67 to -0.16) showed program effectiveness. Reach was broad across 41 towns with 62% of participants reporting influencing some of the health behaviors of their families. Strong implementation fidelity was achieved with good retention rates at 1 year (76%) and high participant satisfaction (82% of participants willing to recommend this program). Over 300 multi-level community partnerships were established supporting high adoption. Stakeholders reported potential capacity to implement and sustain the prevention program in resource poor rural settings, due to the low-intensity design and minimal resources required.

CONCLUSIONS

Our comprehensive RE-AIM evaluation demonstrates that an evidence-based obesity prevention program can be successfully implemented in real-world settings. The program achieved broad reach, effectiveness, and satisfaction at the community and stakeholder level, revealing potential for program sustainability. The evaluation addressed implementation knowledge gaps to support future obesity prevention program scale-up.

TRIAL REGISTRATION

Australian and New Zealand Clinical Trial Registry ACTRN 12612000115831 [ http://www.anzctr.org.au/ ].

Breastfeeding and the incidence of endometrial cancer: A meta-analysis

Several epidemiological studies have investigated the association between breastfeeding and endometrial cancer (EC). However, the results of the studies are controversial. Thus, we conduct this meta-analysis to explore the association between breastfeeding and EC and to evaluate the possible does-response relationship between duration of breastfeeding and EC. PubMed, Web of Science, Chinese National Knowledge Infrastructure, China biology medical literature database, Wan fang databases and Database of Chinese Scientific and Technical Periodicals were searched for eligible observational studies up to 11 July 2015. Random effects model was used to calculate the pooled relative risks (RRs) and restricted cubic spline model was adopted for the does-response analysis.

Fifteen articles with 623570 participants were identified. The RRs of these studies suggested that breastfeeding was associated with the reduced risk of EC (high versus low/no: RR = 0.74; 95% confidence interval (CI), 0.58–0.95). In subgroup analyses, a significant association of breastfeeding with EC risk was found in Asia (RR = 0.57, 95% CI 0.37–0.87), and an inverse association of breastfeeding with EC risk was found in cohort studies (RR = 0.62, 95% CI 0.41–0.94). The results were also significant after adjusted for hormone use (RR = 0.63, 95% CI 0.41–0.97) and body mass index (RR=0.65, 95% CI 0.44–0.96). A linear relationship was found of breastfeeding with EC (p for nonlinearity = 0.93), and it indicated that EC risk decreased by 1.2% for one month increment of breastfeeding. This meta-analysis indicates that long term breastfeeding might be associated with decreased risk of EC.

Perioperative support reduces mortality of obese BALB/c mice after ovariectomy

The incidence of obesity is on the rise in most western countries and represents major risks to health. Obesity causes complex metabolic dysfunctions and can be associated with a large number of secondary diseases. To investigate causal mechanisms of obesity and develop better options for treatment, researchers study the condition in animal models. In addition to genetically engineered animal models, diet-induced obesity is often used because it occurs similarly in animals as it does in humans. For several types of investigations that use obesity models, investigators must carry out surgical interventions and they frequently encounter severe perioperative complications induced by anesthesia. In an example of this problem, we observed 100% mortality in obese BALB/c mice after ovariectomy, despite no obvious surgical complications. We supposed that a failure to recover from surgery was the primary cause of this increased mortality. Therefore, to support their recovery from surgery we administered atropine to obese mice in order to facilitate blood circulation, and we also increased the oxygen content of the ambient air. With this specific support before and after surgery, we increased the survival rate of obese ovariectomized mice up to 83%. These results confirm the assumption that obesity is a risk factor for the recovery of obese animal models after ovariectomy, and they highlight the need to provide additional interventions for such experimental animals.

Weight Fluctuation and Postmenopausal Breast Cancer in the National Health and Nutrition Examination Survey I Epidemiologic Follow-Up Study

OBJECTIVE

The aim of this study is to investigate if weight fluctuation is an independent risk factor for postmenopausal breast cancer (PBC) among women who gained weight in adult years.

METHODS

NHANES I Epidemiologic Follow-Up Study (NHEFS) database was used in the study. Women that were cancers-free at enrollment and diagnosed for the first time with breast cancer at age 50 or greater were considered cases. Controls were chosen from the subset of cancers-free women and matched to cases by years of follow-up and status of body mass index (BMI) at 25 years of age. Weight fluctuation was measured by the root-mean-square-error (RMSE) from a simple linear regression model for each woman with their body mass index (BMI) regressed on age (started at 25 years) while women with the positive slope from this regression were defined as weight gainers. Data were analyzed using conditional logistic regression models.

RESULTS

A total of 158 women were included into the study. The conditional logistic regression adjusted for weight gain demonstrated positive association between weight fluctuation in adult years and postmenopausal breast cancers (odds ratio/OR = 1.67; 95% confidence interval/CI: 1.06-2.66).

CONCLUSIONS

The data suggested that long-term weight fluctuation was significant risk factor for PBC among women who gained weight in adult years. This finding underscores the importance of maintaining lost weight and avoiding weight fluctuation.

Preventing Weight Gain in Women in Rural Communities: A Cluster Randomised Controlled Trial

BACKGROUND

Obesity is reaching epidemic proportions in both developed and developing countries. Even modest weight gain increases the risk for chronic illness, yet evidence-based interventions to prevent weight gain are rare. This trial will determine if a simple low-intensity intervention can prevent weight gain in women compared to general health information.

METHODS AND FINDINGS

We conducted a 1-yr pragmatic, cluster randomised controlled trial in 41 Australian towns (clusters) randomised using a computer-generated randomisation list for intervention (n = 21) or control (n = 20). Women aged 18 to 50 yr were recruited from the general population to receive a 1-yr self-management lifestyle intervention (HeLP-her) consisting of one group session, monthly SMS text messages, one phone coaching session, and a program manual, or to a control group receiving one general women's health education session. From October 2012 to April 2014 we studied 649 women, mean age 39.6 yr (+/- SD 6.7) and BMI of 28.8 kg/m(2) (+/- SD 6.9) with the primary outcome weight change between groups at 1 yr. The mean change in the control was +0.44 kg (95% CI -0.09 to 0.97) and in the intervention group -0.48 kg (95% CI -0.99 to 0.03) with an unadjusted between group difference of -0.92 kg (95% CI -1.67 to -0.16) or -0.87 kg (95% CI -1.62 to -0.13) adjusted for baseline values and clustering. Secondary outcomes included improved diet quality and greater self-management behaviours. The intervention appeared to be equally efficacious across all age, BMI, income, and education subgroups. Loss to follow-up included 23.8% in the intervention group and 21.8% in the control group and was within the anticipated range. Limitations include lack of sensitive tools to measure the small changes to energy intake and physical activity. Those who gained weight may have been less inclined to return for 1 yr weight measures.

CONCLUSIONS

A low intensity lifestyle program can prevent the persistent weight gain observed in women. Key features included community integration, nonprescriptive simple health messages, small changes to behaviour, low participant burden, self-weighing, and delivery including a mix of group, phone, and SMS text reminders. The findings support population strategies to halt the rise in obesity prevalence.

Weight cycling and cancer incidence in a large prospective US cohort

Weight cycling, which consists of repeated cycles of intentional weight loss and regain, is common among individuals who try to lose weight. Some evidence suggests that weight cycling may affect biological processes that could contribute to carcinogenesis, but whether it is associated with cancer risk is unclear. Using 62,792 men and 69,520 women enrolled in the Cancer Prevention Study II Nutrition Cohort in 1992, we examined the association between weight cycling and cancer incidence. Weight cycles were defined by using baseline questions that asked the number of times ≥10 pounds (4.54 kg) was purposely lost and later regained. Multivariable-adjusted hazard ratios and 95% confidence intervals for all cancer and 15 individual cancers were estimated by using Cox proportional hazards regression. During up to 17 years of follow-up, 15,333 men and 9,984 women developed cancer. Weight cycling was not associated with overall risk of cancer in men (hazard ratio = 0.96, 95% confidence interval: 0.83, 1.11 for ≥20 cycles vs. no weight cycles) or women (hazard ratio = 0.96, 95% confidence interval: 0.86, 1.08) in models that adjusted for body mass index and other covariates. Weight cycling was also not associated with any individual cancer investigated. These results suggest that weight cycling, independent of body weight, is unlikely to influence subsequent cancer risk.

Breast cancer correlates in a cohort of breast screening program participants in Riyadh, KSA

BACKGROUND

Breast cancer is the first cancer among females in the Kingdom of Saudi Arabia, accounting for 27.4% of all newly diagnosed female cancers in 2010. There are several risk factors affecting the incidence of breast cancer where some factors influence the risk more than the others.

AIM

We aimed to identify the different risk factors related to breast cancer among females participating in the breast-screening program in Riyadh, KSA.

METHODS

Based on data from phase-I of the breast-screening program, a case-control study was conducted on women living in Riyadh, KSA. A sample of 349 women (58 cases and 290 controls) was recruited to examine the different breast cancer correlates. Multivariate regression model was built to investigate the most important risk factors.

RESULTS

The mean age of cases was 48.5±7.1 years. Age at marriage, number of pregnancy, age at menopause, oral contraceptive pills, breast feeding and family history of breast cancer in first-degree relative were identified as the most important correlates among the studied cohort.

CONCLUSIONS

The findings of the current work suggested that age at marriage, age at menopause ⩾50 years and 1st degree family history of breast cancer were risk factors for breast cancer, while, age at menopause <50 years, number of pregnancies and practicing breast feeding were protective factors against breast cancer. There was no effect of body mass index or physical inactivity. Further studies are needed to explore the hereditary, familial and genetic background risk factors in Saudi population.

Weight change in middle adulthood and breast cancer risk in the EPIC-PANACEA study

Long-term weight gain (i.e., weight gain since age 20) has been related to higher risk of postmenopausal breast cancer, but a lower risk of premenopausal breast cancer. The effect of weight change in middle adulthood is unclear. We investigated the association between weight change in middle adulthood (i.e., women aged 40-50 years) and the risk of breast cancer before and after the age of 50. We included female participants of the European Prospective Investigation into Cancer and Nutrition cohort, with information on anthropometric measures at recruitment and after a median follow-up of 4.3 years. Annual weight change was categorized using quintiles taking quintile 2 and 3 as the reference category (-0.44 to 0.36 kg/year). Multivariable Cox proportional hazards regression analysis was used to examine the association. 205,723 women were included and 4,663 incident breast cancer cases were diagnosed during a median follow-up of 7.5 years (from second weight assessment onward). High weight gain (Q5: 0.83-4.98 kg/year) was related to a slightly, but significantly higher breast cancer risk (HRQ5_versus_Q2/3 : 1.09, 95% CI: 1.01-1.18). The association was more pronounced for breast cancer diagnosed before or at age 50 (HRQ5_versus_Q2/3 : 1.37, 95% CI: 1.02-1.85). Weight loss was not associated with breast cancer risk. There was no evidence for heterogeneity by hormone receptor status. In conclusion, high weight gain in middle adulthood increases the risk of breast cancer. The association seems to be more pronounced for breast cancer diagnosed before or at age 50. Our results illustrate the importance of avoiding weight gain in middle adulthood.

Vascular endothelial growth factor (VEGF) gene polymorphisms and breast cancer risk in Punjabi population from North West India

The purpose of this study was to evaluate the association of seven VEGF promoter polymorphisms with breast cancer risk in Punjabi population from North West India. We screened DNA samples of 102 sporadic breast cancer patients and 102 unrelated healthy, gender, and age-matched individuals for seven VEGF promoter polymorphisms [-417 C/T (rs833062), -172 C/A (rs59260042), -165 C/T (rs79469752), -160 C/T, -152 G/A (rs13207351), -141 A/C (rs28357093) and -116 G/A (rs1570360)] by direct sequencing. The frequency of GG, GA, and AA genotype of -152 G/A polymorphism was 26.47 vs 38.34%, 46.08 vs 51.96%, and 27.45 vs 9.80%, in patients and controls, respectively. VEGF -152 AA genotype was significantly associated with increased risk for breast cancer (OR = 4.04, 95%CI, 1.69-9.68, p = 0.001; recessive model OR = 3.48, 95%CI, 1.59-7.63, p = 0.001). For VEGF -116 G/A polymorphism, G and A allele frequencies were 65.2 vs 76.47% and 34.8 vs 23.53% in patients and controls, respectively. Individuals having -116 AA genotype (OR = 3.40; 95%CI, 1.24-9.37; p = 0.014) and A allele (OR = 1.73; 95%CI, 1.12-2.67; p = 0.012) were associated with increased risk for breast cancer. VEGF -165 C/T and -141 A/C polymorphisms were associated with reduced risk for breast cancer. There was significantly decreased frequency of CT genotype (4.90 vs 18.63%; p = 0.002) and T allele (2.45 vs 9.31%; p = 0.003) of -165 C/T polymorphism among breast cancer patients as compared to controls. VEGF -141 A and C allele frequency were 96.57 vs 91.18% and 3.43 vs 8.82% in patients and controls, respectively. Significant reduced risk for breast cancer was observed with AC genotype (OR = 0.34, 95%CI, 0.14-0.86; p = 0.019) and C allele (OR = 0.37; 95%CI, 0.15-0.89; p = 0.023) of -141 A/C polymorphism. We did not observe association of VEGF -417 T/C, -172 C/A, -160 C/T polymorphisms with breast cancer risk in the studied subjects (p > 0.05). The VEGF -152 G/A and -116 G/A polymorphisms were found to be significantly associated with increased risk for breast cancer while -165 C/T and -141 A/C polymorphisms were found to be associated with decreased risk for breast cancer in Punjabi population from North West India.

Weight Loss Reversed Obesity-Induced HGF/c-Met Pathway and Basal-Like Breast Cancer Progression

Epidemiologic studies demonstrate that obesity is associated with an aggressive subtype of breast cancer called basal-like breast cancer (BBC). Using the C3(1)-T_Ag murine model of BBC, we previously demonstrated that mice displayed an early onset of tumors when fed obesogenic diets in the adult window of susceptibility. Obesity was also shown to elevate mammary gland expression and activation of hepatocyte growth factor (HGF)/c-Met compared to lean controls, a pro-tumorigenic pathway associated with BBC in patients. Epidemiologic studies estimate that weight loss could prevent a large proportion of BBC. We sought to investigate whether weight loss in adulthood prior to tumor onset would protect mice from accelerated tumorigenesis observed in obese mice. Using a life-long model of obesity, C3(1)-T_Ag mice were weaned onto and maintained on an obesogenic high-fat diet. Obese mice displayed significant elevations in tumor progression, but not latency or burden. Tumor progression was significantly reversed when obese mice were induced to lose weight by switching to a control low-fat diet prior to tumor onset compared to mice maintained on obesogenic diet. We investigated the HGF/c-Met pathway known to regulate tumorigenesis. Importantly, HGF/c-Met expression in normal mammary glands and c-Met in tumors was elevated with obesity and was significantly reversed with weight loss. Changes in tumor growth could not be explained by measures of HGF action including phospho-AKT or phospho-S6. Other mediators associated with oncogenesis such as hyperinsulinemia and a high leptin:adiponectin ratio were elevated by obesity and reduced with weight loss. In sum, weight loss significantly blunted the obesity-responsive pro-tumorigenic HGF/c-Met pathway and improved several metabolic risk factors associated with BBC, which together may have contributed to the dramatic reversal of obesity-driven tumor progression. Future research aims to evaluate the role of obesity and the HGF/c-Met pathway in basal-like breast cancer progression.

Resveratrol and cancer: focus on in vivo evidence

Resveratrol is a naturally occurring polyphenol that provides a number of anti-aging health benefits including improved metabolism, cardioprotection, and cancer prevention. Much of the work on resveratrol and cancer comes from in vitro studies looking at resveratrol actions on cancer cells and pathways. There are, however, comparatively fewer studies that have investigated resveratrol treatment and cancer outcomes in vivo, perhaps limited by its poor bioavailability when taken orally. Although research in cell culture has shown promising and positive effects of resveratrol, evidence from rodents and humans is inconsistent. This review highlights the in vivo effects of resveratrol treatment on breast, colorectal, liver, pancreatic, and prostate cancers. Resveratrol supplementation in animal models of cancer has shown positive, neutral as well as negative outcomes depending on resveratrol route of administration, dose, tumor model, species, and other factors. Within a specific cancer type, there is variability between studies with respect to strain, age, and sex of animal used, timing and method of resveratrol supplementation, and dose of resveratrol used to study cancer endpoints. Together, the data suggest that many factors need to be considered before resveratrol can be used for human cancer prevention or therapy.

Favorable effects of low-fat and low-carbohydrate dietary patterns on serum leptin, but not adiponectin, among overweight and obese premenopausal women: a randomized trial

PURPOSE

The most effective dietary pattern for breast cancer prevention has been greatly debated in recent years. Studies have examined hypocaloric diets, with particular emphasis on macronutrient composition, yielding inconclusive data. The objective of this study was to examine the effects of calorie-restricted low-fat and low-carbohydrate diets (LFD and LCD, respectively) on circulating adipokines among overweight and obese premenopausal women.

METHODS

Seventy-nine overweight and obese premenopausal women were randomized to either LFD or LCD, with increased physical activity, for 52 weeks. Serum adiponectin, leptin and the adiponectin-to-leptin ratio (A/L) were measured at baseline, and at weeks 34 and 52 to assess intervention effects.

RESULTS

While there were no significant changes in serum adiponectin concentrations following the LCD and LFD interventions, leptin concentrations significantly decreased by week 34 of the intervention period (LCD: 35.3%, P = 0.004; LFD: 30.0%, P = 0.01), with no difference by intervention arm. At week 52, these reductions were statistically non-significant, indicating a return to baseline levels by the end of the intervention. While there were non-significant increases in the A/L ratio following the LCD and LFD intervention arms, the overall trend, across groups, was marginally significant (P = 0.05) with increases of 16.2% and 35.1% at weeks 34 and 52, respectively.

CONCLUSIONS

These findings suggest that caloric-restricted LCD and LFD dietary patterns favorably modify leptin and possibly the A/L ratio, and lend support to the hypothesis that these interventions may be effective for obesity-related breast cancer prevention through their effects on biomarkers involved in metabolic pathways.

TRIAL REGISTRATION

CLINICAL TRIAL REGISTRATION NUMBER

NCT01559194.

Hypothalamic gene transfer of BDNF inhibits breast cancer progression and metastasis in middle age obese mice

Activation of the hypothalamus-adipocyte axis is associated with an antiobesity and anticancer phenotype in animal models of melanoma and colon cancer. Brain-derived neurotrophic factor (BDNF) is a key mediator in the hypothalamus leading to preferential sympathoneural activation of adipose tissue and the ensuing resistance to obesity and cancer. Here, we generated middle age obese mice by high fat diet feeding for a year and investigated the effects of hypothalamic gene transfer of BDNF on a hormone receptor-positive mammary tumor model. The recombinant adeno-associated viral vector-mediated overexpression of BDNF led to marked weight loss and decrease of adiposity without change of food intake. BDNF gene therapy improved glucose tolerance, alleviated steatosis, reduced leptin level, inhibited mouse breast cancer EO771 growth, and prevented the metastasis. The reduced tumor growth in BDNF-treated mice was associated with reduced angiogenesis, decreased proliferation, increased apoptosis, and reduced adipocyte recruitment and lipid accumulation. Moreover, BDNF gene therapy reduced inflammation markers in the hypothalamus, the mammary gland, the subcutaneous fat, and the mammary tumor. Our results suggest that manipulating a single gene in the brain may influence multiple mechanisms implicated in obesity-cancer association and provide a target for the prevention and treatment of both obesity and cancer.

The expression of the estrogen receptor in obese patients with high breast density (HBD)

OBJECTIVE

Obesity has been associated with increased risk for breast cancer (BC) mortality. Verifying in women with high breast density (HBD) post-menopausal, the frequency of polymorphisms of estrogen receptor (ER)α-PvuII, ERα-XbaI and if they influence the body mass index (BMI).

METHODS

Study with 308 women with HBD post-menopause divided into two groups according to BMI: 1st group = BMI < 25 kg/m(2), 2nd group = BMI ≥ 25 kg/m(2). It was characterized in the clinical history: menarche, menopause, parity, family history of BC, smoking and alcohol intake.

RESULTS

Allele and genotype frequencies for the ERα-397-Pvull and ERα-351-XbaI: P = 43.99%, p = 56.01%, pp = 32.14%, Pp = 47.73%, PP = X = 20.13% and X = 41.56%, x = 58.44%; xx = 33.44%; Xx = 50.00%; XX = 16.56%, respectively. Both PvuII and XbaI influenced BMI. When XbaI is mutated the tendency is toward higher BMI (0.039), and women with lower BMI were more frequent in PvuII genotype (p = 0.002). More frequent risk factors for BC: menarche before the age of 12 years (35.38%), nulliparity or 1st child after 28 years old (41.66%), family history of BC (19.16%) and overweight/obesity (62.01%).

CONCLUSION

Variations in the ERα gene affected the BMI in women with HBD, who already are at increased risk for BC.

Body mass index and breast cancer risk according to postmenopausal estrogen-progestin use and hormone receptor status

To assess the joint relationships among body mass index, menopausal status, and breast cancer according to breast cancer subtype and estrogen-progestin medication use, we conducted a meta-analysis of 89 epidemiologic reports published in English during 1980-2012 identified through a systematic search of bibliographic databases. Pooled analysis yielded a summary risk ratio of 0.78 (95% confidence interval (CI): 0.67, 0.92) for hormone receptor-positive premenopausal breast cancer associated with obesity (body mass index (weight (kg)/height (m)(2)) ≥30 compared with <25). Obesity was associated with a summary risk ratio of 1.39 (95% CI: 1.14, 1.70) for receptor-positive postmenopausal breast cancer. For receptor-negative breast cancer, the summary risk ratios of 1.06 (95% CI: 0.70, 1.60) and 0.98 (95% CI: 0.78, 1.22) associated with obesity were null for both premenopausal and postmenopausal women, respectively. Elevated postmenopausal breast cancer risk ratios associated with obesity were limited to women who never took estrogen-progestin therapy, with risk ratios of 1.42 (95% CI: 1.30, 1.55) among never users and 1.18 (95% CI: 0.98, 1.42) among users; too few studies were available to examine this relationship according to receptor subtype. Future research is needed to confirm whether obesity is unrelated to receptor-negative breast cancer in populations of postmenopausal women with low prevalence of hormone medication use.

Female Body Mass Index and its Relationship With Triple Negative Breast Cancer and Ethnicity

BACKGROUND

Breast cancer in women is a relatively common malignancy in the western hemisphere and is perhaps one of the leading causes of mortality among females. We conducted a retrospect cohort study to investigate the association of body mass index (BMI) with triple negative breast cancer and ethnicity.

METHODS

Tumor Registry Database at the University of Florida, College of Medicine in Jacksonville was utilized for our cohort study. A total of 84 women with triple negative breast cancer, between 2004 and 2008 met our criteria and were selected for this study. For comparison, another 83 women with at least one hormone receptors positive breast cancer were randomly selected in the same time period. Chi-square testing was used to evaluate categorical variables, while the t-test analysis was used to analyze for the continuous variables.

RESULTS

Our data demonstrated that 27.4% of the triple negative group had BMI < 25 compared to the 14.5% of non-triple negative breast cancer, 73.6% of the triple negative group had BMI ≥ 25 compared to 86.5% in the non-triple negative group with a P-value of 0.245. In terms of ethnicity, triple negative breast cancer was found in 56% of African-American and 44% of Caucasian females. Non-triple negative breast cancer was found in 48.2% of African-Americans and 51.8% of Caucasians females with a P-value of 0.354.

CONCLUSIONS

We were not able to show any statistically significant association of body mass index triple with triple negative breast cancer or ethnicity. While our findings are not in agreement with the research published earlier, we do submit that our retrospective cohort study has shortcomings, including the small sample size pooled from a single center, which greatly limits our ability to deduce any definitive conclusions. In light of these shortcomings, we recommend a future multicenter study with a larger sample size.

Increased plasma levels of soluble vascular endothelial growth factor receptor 1 (sFlt-1) in women by moderate exercise and increased plasma levels of vascular endothelial growth factor in overweight/obese women

The incidence of breast cancer is increasing worldwide, and this seems to be related to an increase in lifestyle risk factors, including physical inactivity and overweight/obesity. We have reported previously that exercise induced a circulating angiostatic phenotype characterized by increased soluble fms-like tyrosine kinase-1 (sFlt-1) and endostatin and decreased unbound vascular endothelial growth factor (VEGF) in men. However, there are no data on women. The present study determines the following: (a) whether moderate exercise increased sFlt-1 and endostatin and decreased unbound VEGF in the circulation of adult female volunteers and (b) whether overweight/obese women have a higher plasma level of unbound VEGF than lean women. A total of 72 African American and White adult women volunteers ranging in age from 18 to 44 years were enrolled in the exercise study. All the participants walked on a treadmill for 30 min at a moderate intensity (55-59% heart rate reserve), and oxygen consumption (VO(2)) was quantified utilizing a metabolic cart. We obtained blood samples before and immediately after exercise from 63 participants. ELISA assays showed that the plasma levels of sFlt-1 were 67.8±3.7 pg/ml immediately after exercise (30 min), significantly higher than the basal levels, 54.5±3.3 pg/ml, before exercise (P<0.01; n=63). There was no significant difference in the % increase in the sFlt-1 levels after exercise between African American and White (P=0.533) women or between lean and overweight/obese women (P=0.892). There was no significant difference in the plasma levels of unbound VEGF (35.28±5.47 vs. 35.23±4.96 pg/ml; P=0.99) or endostatin (111.12±5.48 vs. 115.45±7.15 ng/ml; P=0.63) before and after exercise. The basal plasma levels of unbound VEGF in overweight/obese women were 52.26±9.6 pg/ml, significantly higher than the basal levels of unbound VEGF in lean women, 27.34±4.99 pg/ml (P<0.05). The results support our hypothesis that exercise-induced plasma levels of sFlt-1 could be an important clinical biomarker to explore the mechanisms of exercise training in reducing the progression of breast cancer and that VEGF is an important biomarker in obesity and obesity-related cancer progression.

Obesity, independent of p53 gene dosage, promotes mammary tumor progression and upregulates the p53 regulator microRNA-504

Obesity, prevalent in >35% of US women, is an established risk and progression factor for postmenopausal breast cancer, and strategies to break the obesity-breast cancer link are urgently needed. Approximately 30% of breast cancers carry p53 tumor suppressor gene alterations; however, the effects of obesity on breast cancer progression in relation to p53 gene dosage are unclear. Using murine models of postmenopausal breast cancer, we characterized the interactive effects of diet-induced obesity (DIO) and p53 gene dosage on mammary tumor growth and associated p53-related regulatory mechanisms. Ovariectomized C57BL/6 mice were randomly assigned to receive a DIO or control diet, and (at 10 weeks) orthotopic injection of MMTV-Wnt-1 p53^+/− or MMTV-Wnt-1 p53^+/+ mammary tumor cells (n = 20 mice per diet and genotype group). DIO and control diets produced distinct phenotypes (mean percent body fat at 10 weeks: 57% and 39%, respectively, P<0.001). Regardless of phenotype, time to first palpable tumor was 57% less for Wnt-1 p53^+/− than Wnt-1 p53^+/+ tumors. Regardless of tumoral p53 genotype, DIO (relative to control) increased tumor burden, tumor cell proliferation (Ki-67), severity of tumor pathology, local tissue invasion, epithelial-to-mesenchymal transition (EMT) programming, and tumoral microRNA-504 (a negative regulator of p53) expression; and suppressed p53, p21, and estrogen receptor-alpha protein expression. These findings in murine models of postmenopausal breast cancer suggest that obesity may augment procancer effects related to p53 gene alterations. Furthermore, microRNA-504, an obesity-responsive negative regulator of p53 and putative EMT regulator, may represent a novel molecular target for breaking the obesity-breast cancer link.

Tumor-suppressive effects of CDK8 in endometrial cancer cells

CDK8 is either amplified or mutated in a variety of human cancers, and CDK8 functions as an oncoprotein in melanoma and colorectal cancers. Previously, we reported that loss or reduction of CDK8 results in aberrant fat accumulation in Drosophila and mammals, suggesting that CDK8 plays an important role in inhibiting lipogenesis. Epidemiological studies have identified obesity and overweight as the major risk factors of endometrial cancer, thus we examined whether CDK8 regulates endometrial cancer cell growth by using several endometrial cancer cell lines, including KLE, which express low levels of CDK8, as well as AN3 CA and HEC-1A cells, which have high levels of endogenous CDK8. We observed that ectopic expression of CDK8 in KLE cells inhibited cell proliferation and potently blocked tumor growth in an in vivo mouse model. In addition, gain of CDK8 in KLE cells blocked cell migration and invasion in transwell, wound healing and persistence of migratory directionality assays. Conversely, we observed the opposite effects in all of the aforementioned assays when CDK8 was depleted in AN3 CA cells. Similar to AN3 CA cells, depletion of CDK8 in HEC-1A cells strongly enhanced cell migration in transwell assays, while overexpression of CDK8 in HEC-1A cells blocked cell migration. Furthermore, gene profiling of KLE cells overexpressing CDK8 revealed genes whose protein products are involved in lipid metabolism, cell cycle and cell movement pathways. Finally, depletion of CDK8 increased the expression of lipogenic genes in endometrial cancer cells. Taken together, these results show a reverse correlation between CDK8 levels and several key features of the endometrial cancer cells, including cell proliferation, migration and invasion as well as tumor formation in vivo. Therefore, in contrast to the oncogenic effects of CDK8 in melanoma and colorectal cancers, our results suggest that CDK8 plays a tumor-suppressive role in endometrial cancers.

The protective effect of intermittent calorie restriction on mammary tumorigenesis is not compromised by consumption of a high fat diet during refeeding

Previously we reported that intermittent calorie restriction (ICR) provided greater prevention of mammary tumors (MTs) than chronic calorie restriction (CCR). Here the impact of increased fat intake during refeeding in an ICR protocol was evaluated. MMTV-TGF-α female mice were assigned to one of three groups: ad libitum (AL) fed (n = 45) with free access to a moderately high fat diet (22 % fat calories); ICR (n = 45) 50 % calorie restricted for 3-week intervals followed by 3 weeks of 100 % of AL intake; and CCR (n = 45) fed 75 % of AL mice, matching each 6-week cycle of ICR mice. ICR mice were further designated as ICR-Restricted or ICR-Refed for data obtained during these intervals. All mice consumed the same absolute amount of dietary fat. Mice were followed to assess MT incidence, body weight and serum IGF-1, IGFBP3, leptin and adiponectin levels until 79 (end of final 3-week restriction) or 82 (end of final 3-weeks refeeding) weeks of age. Age of MT detection was significantly extended for CCR (74 weeks) and ICR (82 weeks) mice, compared to 57.5 weeks for AL mice. MT incidence for AL, ICR and CCR mice was 66.7, 4.4, and 52.3 %, respectively. Mammary and fat pad weights were reduced significantly following 50 % calorie restriction in ICR-Restricted mice compared to AL, CCR and ICR-Refed mice. IGF-1 and leptin levels also tended to be reduced in ICR-Restricted mice over the course of the study while adiponectin was not compared to AL, CCR, and ICR-Refed mice. The adiponectin:leptin ratio was consistently higher following 50 % restriction in ICR-Restricted mice. There was no relationship of IGF-1, leptin, or adiponectin with the presence of MTs in any groups. Thus the manner in which calories are restricted impacts the protective effect of calorie restriction independently of high fat intake.

Body mass index at different adult ages, weight change, and colorectal cancer risk in the National Institutes of Health-AARP Cohort

The authors investigated the relations of body mass index at different ages and adult weight change to incident colorectal cancer risk in the prospective National Institutes of Health-AARP Diet and Health Study (1995-1996), using a subcohort with repeated recall weights (273,679 participants; mean baseline age = 62.8 years). During 2,509,662 person-years follow-up, 4076 incident colorectal cancers were ascertained. For men, an increased risk of colon cancer but not rectal cancer was associated with body mass index at baseline age (per 5-kg/m(2) increase, hazard ratio (HR) = 1.18, 95% confidence interval (CI): 1.11, 1.25), at age 50 years (HR = 1.18, 95% CI: 1.10, 1.26), and at age 35 years (HR = 1.16, 95% CI: 1.07, 1.25) but less so at age 18 years. Weight gained between the ages of 18 and 35 years and between 18 years of age and the baseline age was associated with an increased risk of colon cancer in men (per 0.5-kg/year increase, HR = 1.18, 95% CI: 1.11, 1.25 and HR = 1.29, 95% CI: 1.16, 1.56, respectively). For women, relations throughout were weaker than those observed for men. These findings suggest that weight gains during early to middle adulthood have important influences on colon cancer risk, especially in men.

Redefining the impact of nutrition on breast cancer incidence: is epigenetics involved?

Breast cancer incidence is rising worldwide with an increase in aggressive neoplasias in young women. Possible factors involved include lifestyle changes, notably diet that is known to make an impact on gene transcription. However, among dietary factors, there is sufficient support for only greater body weight and alcohol consumption whereas numerous studies revealing an impact of specific diets and nutrients on breast cancer risk show conflicting results. Also, little information is available from middle- and low-income countries. The diversity of gene expression profiles found in breast cancers indicates that transcription control is critical for the outcome of the disease. This suggests the need for studies on nutrients that affect epigenetic mechanisms of transcription, such as DNA methylation and post-translational modifications of histones. In the present review, a new examination of the relationship between diet and breast cancer based on transcription control is proposed in light of epidemiological, animal and clinical studies. The mechanisms underlying the impact of diets on breast cancer development and factors that impede reaching clear conclusions are discussed. Understanding the interaction between nutrition and epigenetics (gene expression control via chromatin structure) is critical in light of the influence of diet during early stages of mammary gland development on breast cancer risk, suggesting a persistent effect on gene expression as shown by the influence of certain nutrients on DNA methylation. Successful development of breast cancer prevention strategies will require appropriate models, identification of biological markers for rapid assessment of preventive interventions, and coordinated worldwide research to discern the effects of diet.

Comparing an olive oil-enriched diet to a standard lower-fat diet for weight loss in breast cancer survivors: a pilot study

BACKGROUND

Traditional diets that include moderate to high intakes of extra virgin olive oil have been related to a decrease in breast cancer risk. We hypothesized that an olive oil-enriched diet would lead to greater weight loss and acceptance, compared with a standard diet, in women previously diagnosed with invasive breast cancer.

METHODS

Participants consumed a National Cancer Institute (NCI) diet (total fat > 15% and < 30%) and a plant-based olive oil diet (PBOO; > or = 3 tablespoons of olive oil/day) for 8 weeks, each with random assignment to the order. We established a weight loss goal of at least 5% of baseline weight. After completion of the two diet trials, each participant self-selected one of the diets for an additional 6 months of follow-up for weight management. Body measures were done before and after each diet and after follow-up; fasting blood samples were collected after each diet and after follow-up.

RESULTS

Forty-four overweight women started and 28 completed the 44-week protocol. Twelve (80%) of the 15 women who started with the PBOO diet achieved a weight loss of > or = 5% compared to 4 (31%) of the 13 who started with the NCI diet (p < 0.01). Nineteen of the 22 women eligible for follow-up chose the PBOO diet, and all completed the study. Of the 3 women who chose the NCI diet for follow-up, 1 completed the study. The PBOO diet resulted in lower triglycerides (NCI 105 +/- 46 mg/dL, PBOO 96 +/- 37 mg/dL, p = 0.06) and higher high-density lipoprotein cholesterol (HDL-C) (NCI 64 +/- 13 mg/dL, PBOO 68 +/- 12 mg/dL, p = 0.001).

CONCLUSIONS

An olive oil-enriched diet brought about greater weight loss than a lower-fat diet in an 8-week comparison. Moreover, these women chose, overwhelmingly, the olive oil-enriched diet for 6 months of follow-up. An olive oil-enriched diet may be more efficacious for weight loss in breast cancer survivors than a standard lower-fat diet.

A systematic review of the impact of weight loss on cancer incidence and mortality

Obesity is well recognized as a significant risk factor for certain cancers; however, a corresponding risk reduction with weight loss is not yet clearly defined. This review aims to examine the literature investigating the effect of all types of weight loss on cancer incidence and mortality, and to more clearly describe the relationship between these two factors. A literature search identified 34 publications reporting weight loss data in relation to cancer incidence or mortality. All except one were observational studies and the majority used self-reported weights and did not define intentionality of weight loss. 16/34 studies found a significant inverse association between weight loss and cancer incidence or mortality. The remainder returned null findings. The observed association was more consistently seen in studies that investigated the effect of intentional weight loss (5/6 studies) and the risk reduction was greatest for obesity-related cancers and in women. In conclusion, intentional weight loss does result in a decreased incidence of cancer, particularly female obesity-related cancers. However, there is a need for further evaluation of sustained intentional weight loss in the obese with less reliance on self-reported weight data and more focus on male populations.

Insights into the beneficial effect of caloric/ dietary restriction for a healthy and prolonged life

Over the last several years, new evidence has kept pouring in about the remarkable effect of caloric restriction (CR) on the conspicuous bedfellows- aging and cancer. Through the use of various animal models, it is now well established that by reducing calorie intake one can not only increase life span but, also, lower the risk of various age related diseases such as cancer. Cancer cells are believed to be more dependent on glycolysis for their energy requirements than normal cells and, therefore, can be easily targeted by alteration in the energy-metabolic pathways, a hallmark of CR. Apart from inhibiting the growth of transplantable tumors, CR has been also shown to inhibit the development of spontaneous, radiation, and chemically induced tumors. The question regarding the potentiality of the anti-tumor effect of CR in humans has been in part answered by the resistance of a cohort of women, who had suffered from anorexia in their early life, to breast cancer. However, human research on the beneficial effect of CR is still at an early stage and needs further validation. Though the complete mechanism of the anti-tumor effect of CR is far from clear, the plausible involvement of nutrient sensing pathways or IGF-1 pathways proposed for its anti-aging action cannot be overruled. In fact, cancer cell lines, mutant for proteins involved in IGF-1 pathways, failed to respond to CR. In addition, CR decreases the levels of many growth factors, anabolic hormones, inflammatory cytokines, and oxidative markers that are deregulated in several cancers. In this review, we discuss the anti-tumor effect of CR, describing experiments done in vitro in tumor models and in vivo in mouse models in which the tumor was induced by means of radiation or chemical exposure, expressing oncogenes or deleting tumor suppression genes. We also discuss the proposed mechanisms of CR anti-tumor action. Lastly, we argue the necessity of gene expression studies in cancerous versus normal cells upon CR.

Obesity, Diabetes, the Cardiorenal Syndrome, and Risk for Cancer

Numerous epidemiological studies confirm that the prevalence of obesity and the cardiorenal metabolic syndrome (CRS) is extraordinarily high and that the rates have increased dramatically in the last three decades. In addition, epidemiological data demonstrate that obesity, the CRS, and diabetes are inextricably linked and are all associated with an increased incidence of a number of solid tissue cancers. The mechanisms for this association have been examined, including, but not limited to, higher levels of insulin and free levels of insulin-like growth factor and insulin resistance in obesity and the CRS. Mortality, morbidity, and the associated health care costs which are the link between obesity, the CRS, and diabetes are just beginning to be examined. In addition, we review the advantages of implementing lifestyle and surgical changes to modify obesity, lessening the development of the CRS, diabetes, and associated cancers. Epidemiological data regarding the general mechanisms of the pathogenesis of cancers associated with obesity, the CRS, and diabetes (specifically colon, pancreas, esophageal, liver, breast, prostate, thyroid, and renal carcinomas) are reviewed. The mechanisms by which obesity and other components of the CRS contribute to the pathogenesis of these cancers, such as hormone alterations and insulin- and insulin-like growth factor-dependent pathways of tumor pathogenesis, include the attending roles of inflammation and oxidative stress. Emphasis has been placed on obesity as a modifiable risk factor which, when addressed, provides a reduction in the rate of cancer deaths. In a second part to be published in the next issue of this journal, the relationship between diabetes and cancer will be reviewed in detail.

Weight cycling and mortality in a large prospective US study

Weight cycling has been associated with an increased risk of death in some studies, but few studies differentiated weight cycling initiated by intentional weight loss from that initiated by illness. The association of weight cycling with death was examined among 55,983 men and 66,655 women in the Cancer Prevention Study II Nutrition Cohort from 1992 to 2008. A weight cycle was defined as an intentional loss of 10 or more pounds (≥4.5 kg) followed by regain of that weight, and the lifetime number of weight cycles was reported on a questionnaire administered at enrollment in 1992. A total of 15,138 men and 10,087 women died during follow-up, which ended in 2008. Hazard ratios and 95% confidence intervals were estimated using Cox proportional hazards regression models. When the models were adjusted for age only, weight cycling was positively associated with mortality (P for trend < 0.0001). However, after adjustment for body mass index and other risk factors, low numbers of weight cycles (1-4 cycles) were associated with slightly lower mortality rates (hazard ratio (HR) = 0.93, 95% confidence interval (CI): 0.89, 0.97 in men and HR = 0.93, 95% CI: 0.89, 0.98 in women), whereas high numbers of weight cycles (≥20 cycles) were not associated with mortality (HR = 1.03, 95% CI: 0.89, 1.19 in men and HR = 0.99, 95% CI: 0.88, 1.12 in women). These results do not support an increased risk of mortality associated with weight cycling.

Energy restriction and the prevention of breast cancer

Energy restriction (ER) to control weight is a potential strategy for breast cancer prevention. The protective effects of habitual continuous energy restriction (CER) and weight loss on breast tumour formation have been conclusively demonstrated in animal studies over the past 100 years, and more recently in women using data from observational studies and bariatric surgery. Intermittent energy restriction (IER) and intermittent fasting (IF) are possible alternative preventative approaches which may be easier for individuals to undertake and possibly more effective than standard CER. Here, we summarise the available data on CER, IER and IF with special emphasis on their potential for breast cancer prevention. In animals, IER is superior or equivalent to CER with the exception of carcinogen-induced tumour models when initiated soon after carcinogen exposure. There are no human data on IER and breast cancer risk, but three studies demonstrated IER and CER to be equivalent for weight loss. IF regimens also reduce mammary tumour formation in animal models and also led to weight loss in human subjects, but have not been directly compared with CER. Animal and some human data suggest that both IER and IF may differ mechanistically compared with CER and may bring about greater reduction in hepatic and visceral fat stores, insulin-like growth factor 1 (IGF-1) levels and cell proliferation, and increased insulin sensitivity and adiponectin levels. Although IER and IF were first studied 65 years ago, we conclude that further studies are required to assess their values compared with CER.

Effects of energy restriction and wheel running on mammary carcinogenesis and host systemic factors in a rat model

Limiting energy availability via diet or physical activity has health benefits; however, it is not known whether these interventions have similar effects on the development of cancer. Two questions were addressed as follows: (i) Does limiting energy availability by increasing physical activity have the same effect on mammary carcinogenesis as limiting caloric intake? and (ii) Are host systemic factors, implicated as risk biomarkers for breast cancer, similarly affected by these interventions? Female Sprague Dawley rats were injected with 50-mg 1-methyl-1-nitrosourea per kg body weight at 21 days of age and randomized to one of five groups (30 rats per group) as follows: (i) sham running wheel control; (ii) restricted fed to 85% of the sham control; (iii and iv) voluntary running in a motorized activity wheel (37 m/min) to a maximum of 3,500 m/d or 1,750 m/d; and (v) sedentary ad libitum fed control with no access to a running wheel. The three energetics interventions inhibited the carcinogenic response, reducing cancer incidence (P = 0.01), cancer multiplicity (P < 0.001), and cancer burden (P < 0.001) whereas prolonging cancer latency (P = 0.004) although differences among energetics interventions were not significant. Of the plasma biomarkers associated with the development of cancer, the energetics interventions reduced bioavailable insulin-like growth factor-1 (IGF-1), insulin, interleukin-6, serum amyloid protein, TNF-α, and leptin and increased IGF-binding protein 3 (IGFBP-3) and adiponectin. Plasma-fasting glucose, C-reactive protein, estradiol, and progesterone were unaffected. The plasma biomarkers of greatest value in predicting the carcinogenic response were adiponectin > IGF-1/IGFBP-3 > IGFBP-3 > leptin > IGF-1.

Effect of the timing of weight cycling during adulthood on mortality risk in overweight and obese postmenopausal women

Inconsistent results exist for whether or not weight cycling (WgtC) and weight variability (WgtV) increase mortality risk. The aim of this study was to examine the effect of WgtC and WgtV during adulthood on mortality risk. Data was obtained from the Women's Health Initiative (WHI) observational study (OS) dataset, acquired from the National Heart, Lung and Blood Institute (N = 47,473 overweight and obese women; age 50-79 years). Women were categorized (stable; WgtV: weight-gainer or loser; or WgtC) based on weight changes during early (18-35 years), mid (35-50 years), and late (50 years to current age) adulthood. Those with weight changes of <5% during all three time-periods were classified as being stable-weight. Weight-gainers were those with at least one period of weight-gain (≥5%) without a period of weight-loss (≥5%), and weight-losers were those with at least one period of loss without a period of gain during all time-periods. Those who experienced both a period of weight-gain and loss (≥5%) were categorized as WgtC. Compared to stable-weight individuals, WgtC and WgtV across adulthood were not significantly associated with mortality risk when the age-period of weight change was not considered. However, when considering the age period, increased mortality risk was observed for every 5 kg of weight-gain during early (hazard ratio (HR) = 1.04 (1.00-1.07)) or mid-adulthood (HR = 1.05 (1.02-1.08)), or for every 5 kg of weight-loss since mid (HR = 1.12 (1.01-1.24)) or late-adulthood (HR = 1.12 (1.04-1.20)). In conclusion, merely investigating WgtC and WgtV by weight changes across adulthood may not be sufficient to fully describe mortality risk, and the age at which the weight change occurred might be as important to consider.

Body size and the risk of postmenopausal breast cancer subtypes in the California Teachers Study cohort

PURPOSE: To evaluate how the association between body size and breast cancer risk varies by tumor receptor subtype, host factors, and other exposures among women in the California Teachers Study cohort. METHODS: Among 52,642 postmenopausal women, 2,321 developed invasive breast cancer with known estrogen- and progesterone-receptor status (1,652 ER+PR+, 338 ER+PR-, and 312 ER-PR-) between 1995 and 2007. In a subset of 35,529 with waist circumference data, 1,377 developed invasive breast cancer with known ERPR status (991 ER+PR+, 208 ER+PR-, 169 ER-PR-) between 1997 and 2007. Multivariate Cox regression was performed to estimate relative risks (RR) and 95% confidence intervals (CI). RESULTS: Obesity, adult weight gain of ≥40 pounds, greater abdominal adiposity, and greater height increased the risk of ER+PR+ breast cancer. The increased risk associated with postmenopausal obesity was limited to those who did not use hormone therapy (HT) at cohort entry (RR = 1.37; 95% CI, 1.05-1.78 for BMI ≥ 30 vs. < 25 kg/m(2); p-interaction = 0.14) and those who were not overweight or obese at age 18 (p-interaction = 0.06). The increased risk associated with greater abdominal adiposity was limited to those who were not also overweight or obese (p-interaction = 0.01). Neither obesity, abdominal adiposity, nor height was associated with the risk of ER-PR- tumors. CONCLUSIONS: The effects of body size on postmenopausal breast cancer risk differed by hormone receptor subtype, and among women with ER+PR+ tumors, by HT use and early adult body size.

American Cancer Society Guidelines on nutrition and physical activity for cancer prevention: reducing the risk of cancer with healthy food choices and physical activity

The American Cancer Society (ACS) publishes Nutrition and Physical Activity Guidelines to serve as a foundation for its communication, policy, and community strategies and, ultimately, to affect dietary and physical activity patterns among Americans. These Guidelines, published approximately every 5 years, are developed by a national panel of experts in cancer research, prevention, epidemiology, public health, and policy, and they reflect the most current scientific evidence related to dietary and activity patterns and cancer risk. The ACS Guidelines focus on recommendations for individual choices regarding diet and physical activity patterns, but those choices occur within a community context that either facilitates or creates barriers to healthy behaviors. Therefore, this committee presents recommendations for community action to accompany the 4 recommendations for individual choices to reduce cancer risk. These recommendations for community action recognize that a supportive social and physical environment is indispensable if individuals at all levels of society are to have genuine opportunities to choose healthy behaviors. The ACS Guidelines are consistent with guidelines from the American Heart Association and the American Diabetes Association for the prevention of coronary heart disease and diabetes, as well as for general health promotion, as defined by the 2010 Dietary Guidelines for Americans and the 2008 Physical Activity Guidelines for Americans.

Weight cycling and cancer: weighing the evidence of intermittent caloric restriction and cancer risk

Overweight and obese individuals frequently restrict caloric intake to lose weight. The resultant weight loss, however, typically is followed by an equal or greater weight gain, a phenomenon called weight cycling. Most attention to weight cycling has focused on identifying its detrimental effects, but preclinical experiments indicating that intermittent caloric restriction or fasting can reduce cancer risk have raised interest in potential benefits of weight cycling. Although hypothesized adverse effects of weight cycling on energy metabolism remain largely unsubstantiated, there is also a lack of epidemiologic evidence that intentional weight loss followed by regain of weight affects chronic-disease risk. In the limited studies of weight cycling and cancer, no independent effect on postmenopausal breast cancer but a modest enhancement of risk for renal cell carcinoma, endometrial cancer, and non-Hodgkin's lymphoma have been reported. An effect of either intermittent caloric restriction or fasting in protecting against cancer is not supported by the majority of rodent carcinogenesis experiments. Collectively, the data argue against weight cycling and indicate that the objective of energy balance-based approaches to reduce cancer risk should be to strive to prevent adult weight gain and maintain body weight within the normal range defined by body mass index.