Obesity, energy balance, and cancer: new opportunities for prevention

An Overview of Recent Findings that Shed Light on the Connection between Fat and Cancer

Obesity and cancer have been found to have a direct link in epidemiological studies. Obesity raises the risk of cancer and associated chronic disorders. Furthermore, an imbalance of adipokines, like leptins, plays a crucial role in neoplasm pathogenesis, cell migration, and thereby, cancer metastasis. Also, leptin increases human epidermal growth factor receptor 2 (HER2) protein levels through the STAT3-mediated (signal transducer and activator of transcription) upregulation of heat shock protein (Hsp90) in breast cancer cells. It has been noticed that insulin and insulin-like growth factors (IGFs) act as mitosis activators in the host and cancerous breast epithelial cells. The condition of hyperinsulinemia explains the positive association between colorectal cancer and obesity. Furthermore, in prostate cancer, an alteration in sex hormone levels, testosterone and dihydrotestosterone, has been reported to occur, along with increased oxidative stress, which is the actual cause of the tumors. Whereas, there have been two interconnected factors that play a crucial role in the psychological cycle concerned with lung cancer. The review article focuses on all the prospects of etiological mechanisms that have found linkage with obesity and breast, colon, lung, and prostate cancers. Furthermore, the article has also highlighted how these new insights into the processes occur and, due to which reasons, obesity contributes to tumorigenesis. This review provides a detailed discussion on the progression, which can assist in the development of new and innovative techniques to interfere in this process, and it has been supported with insights based on evidence literature on approved clinical treatments for obesity and cancer.

Cholesterol in colorectal cancer: an essential but tumorigenic precursor?

Colorectal cancer (CRC) is one of the most lethal human malignancies, and with the growth of societies and lifestyle changes, the rate of people suffering from it increases yearly. Important factors such as genetics, family history, nutrition, lifestyle, smoking, and alcohol can play a significant role in increasing susceptibility to this cancer. On the other hand, the metabolism of several macromolecules is also involved in the fate of tumors and immune cells. The evidence discloses that cholesterol and its metabolism can play a role in the pathogenesis of several cancers because there appears to be an association between cholesterol levels and CRC, and cholesterol-lowering drugs may reduce the risk. Furthermore, changes or mutations of some involved genes in cholesterol metabolism, such as CYP7A1 as well as signaling pathways, such as mitogen-activated protein kinase (MAPK), can play a role in CRC pathogenesis. This review summarized and discussed the role of cholesterol in the pathogenesis of CRC as well as available cholesterol-related therapeutic approaches in CRC.

Mediterranean diet and olive oil, microbiota, and obesity-related cancers. From mechanisms to prevention

Olive oil (OO) is the main source of added fat in the Mediterranean diet (MD). It is a mix of bioactive compounds, including monounsaturated fatty acids, phytosterols, simple phenols, secoiridoids, flavonoids, and terpenoids. There is a growing body of evidence that MD and OO improve obesity-related factors. In addition, obesity has been associated with an increased risk for several cancers: endometrial, oesophageal adenocarcinoma, renal, pancreatic, hepatocellular, gastric cardia, meningioma, multiple myeloma, colorectal, postmenopausal breast, ovarian, gallbladder, and thyroid cancer. However, the epidemiological evidence linking MD and OO with these obesity-related cancers, and their potential mechanisms of action, especially those involving the gut microbiota, are not clearly described or understood. The goals of this review are 1) to update the current epidemiological knowledge on the associations between MD and OO consumption and obesity-related cancers, 2) to identify the gut microbiota mechanisms involved in obesity-related cancers, and 3) to report the effects of MD and OO on these mechanisms.

Obesity and prostate cancer - microenvironmental roles of adipose tissue

Obesity is known to have important roles in driving prostate cancer aggressiveness and increased mortality. Multiple mechanisms have been postulated for these clinical observations, including effects of diet and lifestyle, systemic changes in energy balance and hormonal regulation and activation of signalling by growth factors and cytokines and other components of the immune system. Over the past decade, research on obesity has shifted towards investigating the role of peri-prostatic white adipose tissue as an important source of locally produced factors that stimulate prostate cancer progression. Cells that comprise white adipose tissue, the adipocytes and their progenitor adipose stromal cells (ASCs), which proliferate to accommodate white adipose tissue expansion in obesity, have been identified as important drivers of obesity-associated cancer progression. Accumulating evidence suggests that adipocytes are a source of lipids that are used by adjacent prostate cancer cells. However, results of preclinical studies indicate that ASCs promote tumour growth by remodelling extracellular matrix and supporting neovascularization, contributing to the recruitment of immunosuppressive cells, and inducing epithelial-mesenchymal transition through paracrine signalling. Because epithelial-mesenchymal transition is associated with cancer chemotherapy resistance and metastasis, ASCs are considered to be potential targets of therapies that could be developed to suppress cancer aggressiveness in patients with obesity.

Effect of a Telephone-Based Lifestyle Intervention on Weight, Body Composition, and Metabolic Biomarkers in Rural Ohio: Results from a Randomized Pilot Study

Rural residents experience higher rates of obesity, obesity-related chronic diseases, and poorer lifestyle. Promoting physical activity and healthy eating are critical for rural residents; however, lack of resources and access barriers limit the feasibility of in-person lifestyle interventions. There is a need to design and deliver remotely accessible lifestyle interventions in this population. This pilot study examined the effect of a telephone-based lifestyle intervention on weight, body composition, lipids, and inflammatory biomarkers among rural Ohio residents. Rural Ohio adults with overweight/obesity (n = 40) were 2:1 randomized to a 15-week telephone-based lifestyle intervention (n = 27) or control group (n = 13). The lifestyle intervention group received weekly telephone counseling sessions emphasizing healthy eating and increasing physical activity. The control group received educational brochures describing physical activity and dietary recommendations. Weight, body composition, fasting blood lipids, and inflammatory biomarkers were objectively measured at baseline and 15 weeks at local community centers (trial registration#: NCT05040152 at ClinicalTrial.gov). Linear mixed models were used to examine change over time by group. Participants were mostly female, with an average age of 49 years. Over the 15-week trial, the lifestyle intervention showed superior improvements in total cholesterol (∆ = -18.7 ± 7.8 mg/dL, p = 0.02) and LDL (∆ = -17.1 ± 8.1 mg/dL, p = 0.04) vs. control, whereas no significant between-group differences in weight, body composition, or inflammation were observed. Our findings suggest that a 15-week telephone-based lifestyle intervention may offer metabolic benefits that reduce disease risk in rural adults with obesity. Future large-scale studies are needed to determine the efficacy of remotely accessible lifestyle interventions in rural populations, with the goal of reducing obesity-related disparities.

A review of the impact of energy balance on triple-negative breast cancer

Cancer cells cannot proliferate without sufficient energy to generate biomass for rapid cell division, as well as to fuel their functions at baseline. For this reason, many recent observational and interventional studies have focused on increasing energy expenditure and/or reducing energy intake during and after cancer treatment. The impact of variance in diet composition and in exercise on cancer outcomes has been detailed extensively elsewhere and is not the primary focus of this review. Instead, in this translational, narrative review we examine studies of how energy balance impacts anticancer immune activation and outcomes in triple-negative breast cancer (TNBC). We discuss preclinical, clinical observational, and the few clinical interventional studies on energy balance in TNBC. We advocate for the implementation of clinical studies to examine how optimizing energy balance-through changes in diet and/or exercise-may optimize the response to immunotherapy in people with TNBC. It is our conviction that by taking a holistic approach that includes energy balance as a key factor to be considered during and after treatment, cancer care may be optimized, and the detrimental effects of cancer treatment and recovery on overall health may be minimized.

[Effect of Interactions Among Obesity-Related Proteins on Breast Cancer Risk: A Preliminary Study]

Objective

To explore the potential interactions among obesity-related proteins in the pathogenic process of breast cancer (BC) in women.

Methods

We conducted a case-control study, enrolling 279 primary breast cancer cases and 260 age-frequency-matched healthy women between April 2014 and May 2015. Based on the evidence of previous published literature on obesity-related proteins and BC risks, we selected proteins that received more attention and measured the plasma levels of these proteins by enzyme-linked immunosorbent assay (ELISA). After stratification of the subjects according to their menopausal status, an analytic strategy combining multivariate logistic regression and generalized multifactor dimensionality reduction (GMDR) was used to explore the effect of the possible interactions of these proteins on BC risk.

Results

There were marginal high-order interactions among insulin-like growth factor 1 (IGF-1), insulin-like growth factor binding protein 3 (IGFBP-3), C-reactive protein (CRP), resistin (RETN), soluble leptin receptor (sOB-R), and adiponectin (ADP) in premenopausal women (with the balanced accuracy for the testing set being 59.01%, cross-validation consistency being 10/10, and permutation test P=0.05). There were high-order interactions among leptin (LEP), sOB-R, ADP, CRP, IGFBP3 and visfatin (VF) in postmenopausal women (with the balanced accuracy for the testing set being 67.31%, cross-validation consistency being 10/10, and permutation test P=0.01). Along with an increase in the number of obesity-related proteins to which the subjects were exposed, the risk of developing breast cancer gradually increased in both pre- and postmenopausal women ( OR pre =2.18, 95% CI: 1.69-2.82; OR post =2.41, 95% CI: 1.75-3.32).

Conclusions

This preliminary study suggested high-order interactions among obesity-related proteins on BC risk in both pre- and postmenopausal women. In future studies, close attention should be given to these potential interactions when these proteins are used jointly as predictors, as well as in developing a comprehensive risk scoring system for BC.

Association Between Recreational Physical Activity and mTOR Signaling Pathway Protein Expression in Breast Tumor Tissue

Physical activity (PA) is associated with decreased signaling in the mTOR pathway in animal models of mammary cancer, which may indicate favorable outcomes. We examined the association between PA and protein expression in the mTOR signaling pathway in breast tumor tissue. Data on 739 patients with breast cancer, among which 125 patients had adjacent-normal tissue, with tumor expression for mTOR, phosphorylated (p)-mTOR, p-AKT, and p-P70S6K were analyzed. Self-reported recreational PA levels during the year prior to diagnosis were classified using the Centers for Disease Control and Prevention guideline as sufficient (for moderate or vigorous) PA or insufficient PA (any PA but not meeting the guideline) or no PA. We performed linear models for mTOR protein and two-part gamma hurdle models for phosphorylated proteins. Overall, 34.8% of women reported sufficient PA; 14.2%, insufficient PA; 51.0%, no PA. Sufficient (vs. no) PA was associated with higher expression for p-P70S6K [35.8% increase; 95% confidence interval (CI), 2.6-80.2] and total phosphoprotein (28.5% increase; 95% CI, 5.8-56.3) among tumors with positive expression. In analyses stratified by PA intensity, sufficient versus no vigorous PA was also associated with higher expression levels of mTOR (beta = 17.7; 95% CI, 1.1-34.3) and total phosphoprotein (28.6% higher; 95% CI, 1.4-65.0 among women with positive expression) in tumors. The study found that guideline-concordant PA levels were associated with increased mTOR signaling pathway activity in breast tumors. Studying PA in relation to mTOR signaling in humans may need to consider the complexity of the behavioral and biological factors.

Significance

PA increases energy expenditure and limits energy utilization in the cell, which can influence the mTOR pathway that is central to sensing energy influx and regulating cell growth. We studied exercise-mediated mTOR pathway activities in breast tumor and adjacent-normal tissue. Despite the discrepancies between animal and human data and the limitations of our approach, the findings provide a foundation to study the mechanisms of PA and their clinical implications.

Eating habits, anthropometry, lifestyle, and hypertension of a group of non-village indigenous women in Amazon, Brazil

OBJECTIVE

The aim of this study was to describe the anthropometric characteristics, eating habits, and lifestyle of non-village indigenous women living in Manaus, AM, and their association with hypertension.

METHODS

This cross-sectional (descriptive-analytical) study was carried out from January 2020 to December 2021 using a questionnaire for clinical, sociodemographic, and behavioral data. Non-pregnant women who belonged to Parque das Tribos for more than a year, declared themselves indigenous, and were over 18 years of age were included in the study.

RESULTS

In total, 21 ethnicities were identified, and 95 indigenous women were evaluated. The average age group was 36±12.1 years, the average height was 157 cm, and the body mass index was 28.8 kg/m2. The prevalence of systemic arterial hypertension was ±40%, and 68.5% had excess weight, with 29.1% having class I obesity. In all, 35.8% consumed a lot of salt, sugar, and industrialized foods, and 88.4% were sedentary.

CONCLUSION

Much of the sample presented excess weight, and almost all were sedentary. More than one-third had unappropriated eating habits. Hypertension was present in more than one-third of these indigenous women. There was an association between higher body mass index and hypertension. Knowing the characteristics of this group of non-village indigenous women may help determine the best health approach. The data demonstrate the necessity of preventive measures.

Postdiagnosis body fatness, weight change and breast cancer prognosis: Global Cancer Update Program (CUP global) systematic literature review and meta-analysis

Previous evidence on postdiagnosis body fatness and mortality after breast cancer was graded as limited-suggestive. To evaluate the evidence on body mass index (BMI), waist circumference, waist-hip-ratio and weight change in relation to breast cancer prognosis, an updated systematic review was conducted. PubMed and Embase were searched for relevant studies published up to 31 October, 2021. Random-effects meta-analyses were conducted to estimate summary relative risks (RRs). The evidence was judged by an independent Expert Panel using pre-defined grading criteria. One randomized controlled trial and 225 observational studies were reviewed (220 publications). There was strong evidence (likelihood of causality: probable) that higher postdiagnosis BMI was associated with increased all-cause mortality (64 studies, 32 507 deaths), breast cancer-specific mortality (39 studies, 14 106 deaths) and second primary breast cancer (11 studies, 5248 events). The respective summary RRs and 95% confidence intervals per 5 kg/m2 BMI were 1.07 (1.05-1.10), 1.10 (1.06-1.14) and 1.14 (1.04-1.26), with high between-study heterogeneity (I2  = 56%, 60%, 66%), but generally consistent positive associations. Positive associations were also observed for waist circumference, waist-hip-ratio and all-cause and breast cancer-specific mortality. There was limited-suggestive evidence that postdiagnosis BMI was associated with higher risk of recurrence, nonbreast cancer deaths and cardiovascular deaths. The evidence for postdiagnosis (unexplained) weight or BMI change and all outcomes was graded as limited-no conclusion. The RCT showed potential beneficial effect of intentional weight loss on disease-free-survival, but more intervention trials and well-designed observational studies in diverse populations are needed to elucidate the impact of body composition and their changes on breast cancer outcomes.

The feasibility of a telephone-based weight loss intervention in rural Ohio: A pilot study

BACKGROUND

Weight loss through lifestyle modification can produce health benefits and may reduce cancer risk. The goal of this study was to examine the feasibility of and adherence to a 15-week telephone-based weight loss intervention in rural Ohio, an area with high rates of obesity.

METHODS

This pilot 2-arm randomized controlled study was designed for rural Ohio residents who were overweight or obese. Eligible participants were 2:1 randomly assigned to either a 15-week weight loss intervention group or active control group. The weight loss intervention group received weekly telephone sessions to improve healthy diet and increase physical activity. The active control group received education brochures with information on physical activity and dietary guidelines. Feasibility was defined as at least 80% of participants completing the follow-up surveys, and acceptable adherence was defined as the percentage of participants in the weight loss group who attend ≥75% of weekly telephone sessions.

RESULTS

A total of 423 individuals entered the online screening survey, 215 (50.8%) completed the survey, and 98 (45.6%) of those were eligible. Forty eligible individuals were enrolled and randomly assigned to the weight loss group (n = 27) or active control group (n = 13). The average age of the weight loss group was 49 (SD = 10) years, and 89% were female. The average age of the active control group was 51 (SD = 9) years, and 92% were female. Feasibility was demonstrated: 90% of participants completed the online follow-up surveys at 15-weeks. Among participants in the weight loss group, 22 out of 27 (81.5%) completed the 15-week intervention, the average number of sessions attended was 9.7 (64.9%). Adherence to the intervention was rated as acceptable among almost half of the group (48.1%).

CONCLUSIONS

Feasibility of a 15-week telephone-based weight loss study among rural residents with overweight/obesity were determined. A future study will test this intervention for weight loss efficacy.

Myeloid-derived suppressor cells: Cancer, autoimmune diseases, and more

Although cancer immunotherapy using immune checkpoint inhibitors (ICIs) has been recognized as one of the major treatment modalities for malignant diseases, the clinical outcome is not uniform in all cancer patients. Myeloid-derived suppressor cells (MDSCs) represent a heterogeneous population of immature myeloid cells that possess various strong immunosuppressive activities involving multiple immunocompetent cells that are significantly accumulated in patients who did not respond well to cancer immunotherapies. We reviewed the perspective of MDSCs with emerging evidence in this review. Many studies on MDSCs were performed in malignant diseases. Substantial studies on the participation of MDSCs on non-malignant diseases such as chronic infection and autoimmune diseases, and physiological roles in obesity, aging, pregnancy and neonates have yet to be reported. With the growing understanding of the roles of MDSCs, variable therapeutic strategies and agents targeting MDSCs are being investigated, some of which have been used in clinical trials. More studies are required in order to develop more effective strategies against MDSCs.

Impact of obesity and white adipose tissue inflammation on the omental microenvironment in endometrial cancer

BACKGROUND

A complex relationship between adipose tissue and malignancy, involving an inflammatory response, has been reported. The goal of this work was to assess the prevalence of white adipose tissue (WAT) inflammation in patients with endometrial cancer (EC), and the association with circulating inflammation markers. Furthermore, the aim was to characterize the pathways activated in and the cell type composition of adipose tissue in patients with EC.

METHODS

Adipose tissue and blood samples were prospectively collected from 101 patients with EC at initial surgery. WAT inflammation was determined based on adipocytes surrounded by macrophages forming crown-like structures. Circulating levels of metabolic syndrome-associated and inflammatory markers were quantified. RNA-sequencing was performed on adipose samples (n = 55); differential gene expression, pathway, and cellular decomposition analyses were performed using state-of-the-art bioinformatics methods.

RESULTS

WAT inflammation was identified in 46 (45.5%) of 101 EC patients. Dyslipidemia, hypertension, and diabetes mellitus were significantly associated with WAT inflammation (p < .05). WAT inflammation was associated with greater body mass index (p < .001) and higher circulating levels of leptin, high-sensitivity C-reactive protein, and interleukin-6, as well as lower levels of adiponectin and sex hormone-binding globulin (p < .05). Transcriptomic analysis demonstrated increased levels of proinflammatory and pro-neoplastic-related gene expression in inflamed omental adipose tissue.

CONCLUSIONS

WAT inflammation is associated with metabolic syndrome, obesity, and inflammatory markers, as well as increased expression of proinflammatory and proneoplastic genes.

Blood biomarkers reflect the effects of obesity and inflammation on the human breast transcriptome

Obesity is a risk factor for the development of post-menopausal breast cancer. Breast white adipose tissue (WAT) inflammation, which is commonly found in women with excess body fat, is also associated with increased breast cancer risk. Both local and systemic effects are probably important for explaining the link between excess body fat, adipose inflammation and breast cancer. The first goal of this cross-sectional study of 196 women was to carry out transcriptome profiling to define the molecular changes that occur in the breast related to excess body fat and WAT inflammation. A second objective was to determine if commonly measured blood biomarkers of risk and prognosis reflect molecular changes in the breast. Breast WAT inflammation was assessed by immunohistochemistry. Bulk RNA-sequencing was carried out to assess gene expression in non-tumorous breast. Obesity and WAT inflammation were associated with a large number of differentially expressed genes and changes in multiple pathways linked to the development and progression of breast cancer. Altered pathways included inflammatory response, complement, KRAS signaling, tumor necrosis factor α signaling via NFkB, interleukin (IL)6-JAK-STAT3 signaling, epithelial mesenchymal transition, angiogenesis, interferon γ response and transforming growth factor (TGF)-β signaling. Increased expression of several drug targets such as aromatase, TGF-β1, IDO-1 and PD-1 were observed. Levels of various blood biomarkers including high sensitivity C-reactive protein, IL6, leptin, adiponectin, triglycerides, high-density lipoprotein cholesterol and insulin were altered and correlated with molecular changes in the breast. Collectively, this study helps to explain both the link between obesity and breast cancer and the utility of blood biomarkers for determining risk and prognosis.

Insulin-like Growth Factor 2 mRNA-Binding Protein 2-a Potential Link Between Type 2 Diabetes Mellitus and Cancer

CONTEXT

Type 2 diabetes mellitus (T2DM) and cancer share a variety of risk factors and pathophysiological features. It is becoming increasingly accepted that the 2 diseases are related, and that T2DM increases the risk of certain malignancies.

OBJECTIVE

This review summarizes recent advancements in the elucidation of functions of insulin-like growth factor 2 (IGF-2) messenger RNA (mRNA)-binding protein 2 (IGF2BP2) in T2DM and cancer.

METHODS

A PubMed review of the literature was conducted, and search terms included IGF2BP2, IMP2, or p62 in combination with cancer or T2DM. Additional sources were identified through manual searches of reference lists. The increased risk of multiple malignancies and cancer-associated mortality in patients with T2DM is believed to be driven by insulin resistance, hyperinsulinemia, hyperglycemia, chronic inflammation, and dysregulation of adipokines and sex hormones. Furthermore, IGF-2 is oncogenic, and its loss-of-function splice variant is protective against T2DM, which highlights the pivotal role of this growth factor in the pathogenesis of these 2 diseases. IGF-2 mRNA-binding proteins, particularly IGF2BP2, are also involved in T2DM and cancer, and single-nucleotide variations (formerly single-nucleotide polymorphisms) of IGF2BP2 are associated with both diseases. Deletion of the IGF2BP2 gene in mice improves their glucose tolerance and insulin sensitivity, and mice with transgenic p62, a splice variant of IGF2BP2, are prone to diet-induced fatty liver disease and hepatocellular carcinoma, suggesting the biological significance of IGF2BP2 in T2DM and cancer.

CONCLUSION

Accumulating evidence has revealed that IGF2BP2 mediates the pathogenesis of T2DM and cancer by regulating glucose metabolism, insulin sensitivity, and tumorigenesis. This review provides insight into the potential involvement of this RNA binding protein in the link between T2DM and cancer.

Energy status dictates PD-L1 protein abundance and anti-tumor immunity to enable checkpoint blockade

Aberrant energy status contributes to multiple metabolic diseases, including obesity, diabetes, and cancer, but the underlying mechanism remains elusive. Here, we report that ketogenic-diet-induced changes in energy status enhance the efficacy of anti-CTLA-4 immunotherapy by decreasing PD-L1 protein levels and increasing expression of type-I interferon (IFN) and antigen presentation genes. Mechanistically, energy deprivation activates AMP-activated protein kinase (AMPK), which in turn, phosphorylates PD-L1 on Ser283, thereby disrupting its interaction with CMTM4 and subsequently triggering PD-L1 degradation. In addition, AMPK phosphorylates EZH2, which disrupts PRC2 function, leading to enhanced IFNs and antigen presentation gene expression. Through these mechanisms, AMPK agonists or ketogenic diets enhance the efficacy of anti-CTLA-4 immunotherapy and improve the overall survival rate in syngeneic mouse tumor models. Our findings reveal a pivotal role for AMPK in regulating the immune response to immune-checkpoint blockade and advocate for combining ketogenic diets or AMPK agonists with anti-CTLA4 immunotherapy to combat cancer.

Metabolic syndrome risk components and mortality after triple-negative breast cancer diagnosis in postmenopausal women in the Women's Health Initiative

BACKGROUND

Triple-negative breast cancer (TNBC) has a high recurrence risk and poor clinical outcomes. Associations between metabolic syndrome (MetS) risk components and mortality in postmenopausal women with TNBC were examined in the Women's Health Initiative.

METHODS

Five hundred forty-four postmenopausal women were diagnosed with nonmetastatic TNBC. Baseline risk components included a high waist circumference (≥88 cm), high blood pressure, hypercholesterolemia, and diabetes. Groups were categorized by the number of MetS risk components: none, 1 or 2, or 3 or 4. Hazard ratios (HRs) and 95% confidence intervals (CIs) across groups were computed with multivariable adjusted Cox models. Outcomes included breast cancer-specific mortality and breast cancer overall mortality (breast cancer followed by death from any cause). Variables in the multivariable model included age at TNBC diagnosis; race/ethnicity; income; education; clinical/observational trial status; history of oral contraceptive, hormone, and/or statin use; cancer stage; and chemotherapy and/or radiation treatment status.

RESULTS

Of the 544 participants with TNBC, 33% had no MetS risk components (n = 178), 59% had 1 or 2 risk components (n = 323), and 8% had 3 or 4 risk components (n = 43). After a median follow-up from diagnosis of 8.3 years, multivariable results showed that women with 3 or 4 risk components had a nonsignificantly higher risk of breast cancer mortality (HR, 2.05; 95% CI, 0.94-4.47 trend P = .114) and a significantly higher risk of overall mortality (HR, 2.13; 95% CI, 1.22-3.71; trend P = .006) versus women with 0 risk components.

CONCLUSIONS

Postmenopausal women with TNBC and 3 or 4 MetS risk components have a nonsignificantly higher breast cancer mortality risk and a significantly higher overall mortality risk, likely because of negative influences of metabolic risk factors on several causes of death.

Cancer Risk in Normal Weight Individuals with Metabolic Obesity: A Narrative Review

Obesity represents one of the most significant public health challenges worldwide. Current clinical practice relies on body mass index (BMI) to define the obesity status of an individual, even though the index has long been recognized for its limitations as a measure of body fat. In normal BMI individuals, increased central adiposity has been associated with worse health outcomes, including increased risks of cardiovascular disease and metabolic disorders. The condition leading to these outcomes has been described as metabolic obesity in the normal weight (MONW). More recent evidence suggests that MONW is associated with increased risk of several obesity-related malignancies, including postmenopausal breast, endometrial, colorectal, and liver cancers. In MONW patients, the false reassurance of a normal range BMI can lead to lost opportunities for implementing preventive interventions that may benefit a substantial number of people. A growing body of literature has documented the increased risk profile of MONW individuals and demonstrated practical uses for body composition and biochemical analyses to identify this at-risk population. In this review, we survey the current literature on MONW and cancer, summarize pathophysiology and oncogenic mechanisms, highlight potential strategies for diagnosis and treatment, and suggest directions for future research.

Impact of obesity on risk of cancer

Epidemiological data consistently show sustained upward trend in the incidence of cancer. The International Agency for Research on Cancer (IARC) estimated that in 2018 more than 18 million people were diagnosed with cancer, and in about 9.6 million cases cancer could be the cause of death. At the same time, an increasing percentage of overweight and obesity is observed in both adults and children. According to the World Health Organization (WHO), in 2016 over 1.9 billion (39% of the population) of adults were overweight, of which over 650 million (13%) were obese. Obesity is closely related to the risk of cancer development. Excessive body weight is considered as a second risk factor for the development of specific cancers after smoking. According to IARC data, high BMI index may be the cause of up to half a million cancer cases per year. In addition, overweight and obesity contribute to increased mortality due to malignancies - it is estimated that they are the cause of death in 20% of women and in 14% of men. Data from the American Cancer Society indicate increased mortality due to pancreatic cancer, liver cancer, multiple myeloma, and Hodgkin's lymphoma in connection with the occurrence of excessive body weight. The study tried to confirm the influence of obesity on the risk of cancer. To achieve this, risk factors such as excessive adipose tissue, chronic inflammation, hyperinsulinaemia and hyperglycaemia, sex steroids, and microbiome were taken into account. In addition, the study presents a simple method of estimating the risk quotient of chances of developing malignant tumors in people with excessive body mass and methods of cancer disease prevention. According to the current state of knowledge, the modification of factors significantly affecting the risk of falling ill may contribute to reducing the risk of cancer. In view of the above, the importance of the problem of overweight and obesity in society and their impact on the occurrence of some types of cancer should be emphasized. Thus, the understanding of excessive body weight as a serious health and social problem sets one of the priorities in the area of public health.

Association Between Obesity and Histological Tumor Budding in Patients With Nonmetastatic Colon Cancer

IMPORTANCE

Obesity is associated with increased risk of colorectal cancer (CRC) and a more aggressive disease course. Tumor budding (TB) is an important prognostic factor for CRC, but its association with obesity is unknown.

OBJECTIVE

To evaluate the association of TB with obesity and other prognostic factors in colon cancer.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study involved a histological review of colon cancer specimens obtained during 7 years (January 2008 to December 2015) at the University of Kentucky Medical Center; data analysis was conducted from February 2020 to January 2021. Specimens came from 200 patients with stage I to III colon cancer; patients with stage 0, stage IV, or incomplete data were excluded.

MAIN OUTCOMES AND MEASURES

TB was defined as 1 to 4 malignant cells at the invasive edge of the tumor, independently assessed by 2 academic pathologists. The primary outcome was the association of TB with obesity (defined as body mass index [BMI] of 30 or greater). Secondary outcomes include the association of TB with clinical features (ie, age, race, sex, TNM stage, tumor location) and pathological features (ie, poorly differentiated tumor clusters [PDCs], Klintrup-Mäkinen inflammatory score, desmoplasia, infiltrative tumor border, tumor necrosis, and tumor-to-stroma ratio).

RESULTS

A total of 200 specimens were reviewed. The median (interquartile range) age of patients was 62 (55-72) years, 102 (51.0%) were women, and the mean (SD) BMI was 28.5 (8.4). A total of 57 specimens (28.5%) were from stage I tumors; 74 (37.0%), stage II; and 69 (34.5%), stage III. Of these, 97 (48.5%) had low-grade (<5 buds), 36 (18.0%) had intermediate-grade (5-9 buds), and 67 (33.5%) had high-grade (≥10 buds) TB. Multivariable analysis adjusting for clinical and histological factors demonstrated that higher TB grade was associated with obesity (odds ratio [OR], 4.25; 95% CI, 1.95-9.26), higher PDC grade (grade 2 vs 1: OR, 9.14; 95% CI, 3.49-23.93; grade 3 vs 1: OR, 5.10; 95% CI, 2.30-11.27), increased infiltrative tumor border (OR, 1.03; 95% CI, 1.01-1.04), cecal location (OR, 2.55; 95% CI, 1.09-5.97), and higher stage (eg, stage III vs stage I for high-grade or intermediate-grade vs low-grade TB: OR, 2.91; 95% CI, 1.00-8.49). Additionally, patients with a higher TB grade had worse overall survival (intermediate vs low TB: hazard ratio, 2.20; 95% CI, 1.11-4.35; log-rank P = .02; high vs low TB: hazard ratio, 2.67; 95% CI, 1.45-4.90; log-rank P < .001).

CONCLUSIONS AND RELEVANCE

In this cohort study, a novel association between high TB grade and obesity was found. The association could reflect a systemic condition (ie, obesity) locally influencing aggressive growth (ie, high TB) in colon cancer.

Using genetic variants to evaluate the causal effect of cholesterol lowering on head and neck cancer risk: A Mendelian randomization study

Head and neck squamous cell carcinoma (HNSCC), which includes cancers of the oral cavity and oropharynx, is a cause of substantial global morbidity and mortality. Strategies to reduce disease burden include discovery of novel therapies and repurposing of existing drugs. Statins are commonly prescribed for lowering circulating cholesterol by inhibiting HMG-CoA reductase (HMGCR). Results from some observational studies suggest that statin use may reduce HNSCC risk. We appraised the relationship of genetically-proxied cholesterol-lowering drug targets and other circulating lipid traits with oral (OC) and oropharyngeal (OPC) cancer risk using two-sample Mendelian randomization (MR). For the primary analysis, germline genetic variants in HMGCR, NPC1L1, CETP, PCSK9 and LDLR were used to proxy the effect of low-density lipoprotein cholesterol (LDL-C) lowering therapies. In secondary analyses, variants were used to proxy circulating levels of other lipid traits in a genome-wide association study (GWAS) meta-analysis of 188,578 individuals. Both primary and secondary analyses aimed to estimate the downstream causal effect of cholesterol lowering therapies on OC and OPC risk. The second sample for MR was taken from a GWAS of 6,034 OC and OPC cases and 6,585 controls (GAME-ON). Analyses were replicated in UK Biobank, using 839 OC and OPC cases and 372,016 controls and the results of the GAME-ON and UK Biobank analyses combined in a fixed-effects meta-analysis. We found limited evidence of a causal effect of genetically-proxied LDL-C lowering using HMGCR, NPC1L1, CETP or other circulating lipid traits on either OC or OPC risk. Genetically-proxied PCSK9 inhibition equivalent to a 1 mmol/L (38.7 mg/dL) reduction in LDL-C was associated with an increased risk of OC and OPC combined (OR 1.8 95%CI 1.2, 2.8, p = 9.31 x10-05), with good concordance between GAME-ON and UK Biobank (I2 = 22%). Effects for PCSK9 appeared stronger in relation to OPC (OR 2.6 95%CI 1.4, 4.9) than OC (OR 1.4 95%CI 0.8, 2.4). LDLR variants, resulting in genetically-proxied reduction in LDL-C equivalent to a 1 mmol/L (38.7 mg/dL), reduced the risk of OC and OPC combined (OR 0.7, 95%CI 0.5, 1.0, p = 0.006). A series of pleiotropy-robust and outlier detection methods showed that pleiotropy did not bias our findings. We found limited evidence for a role of cholesterol-lowering in OC and OPC risk, suggesting previous observational results may have been confounded. There was some evidence that genetically-proxied inhibition of PCSK9 increased risk, while lipid-lowering variants in LDLR, reduced risk of combined OC and OPC. This result suggests that the mechanisms of action of PCSK9 on OC and OPC risk may be independent of its cholesterol lowering effects; however, this was not supported uniformly across all sensitivity analyses and further replication of this finding is required.

Crossroad between Obesity and Gastrointestinal Cancers: A Review of Molecular Mechanisms and Interventions

The burden of gastrointestinal (GI) cancer is increasing worldwide, and in the past decade, cancer had entered the list of chronic debilitating diseases whose risk is substantially increased by hypernutrition. Obesity may increase the risk of cancer by the imbalance of various mechanisms including insulin and insulin-like growth factor1 (IGF-I) signaling, systemic inflammation, immune dysregulation, tumor angiogenesis, adipokines secretion, and intestinal microbiota that usually act interdependently. An increased understanding of the mechanisms underlying obesity-GI cancer link can provide multiple opportunities for cancer prevention. This review discusses various mechanisms involved molecular mechanisms linking obesity with GI cancers including esophagus, stomach, colorectal and hepatocellular. Furthermore, an optional intervention such as diet restriction and exercise is described, which may be preventive or therapeutic in GI cancer.

Another Weapon against Cancer and Metastasis: Physical-Activity-Dependent Effects on Adiposity and Adipokines

Physically active behavior has been associated with a reduced risk of developing certain types of cancer and improved psychological conditions for patients by reducing anxiety and depression, in turn improving the quality of life of cancer patients. On the other hand, the correlations between inactivity, sedentary behavior, and overweight and obesity with the risk of development and progression of various cancers are well studied, mainly in middle-aged and elderly subjects. In this article, we have revised the evidence on the effects of physical activity on the expression and release of the adipose-tissue-derived mediators of low-grade chronic inflammation, i.e., adipokines, as well as the adipokine-mediated impacts of physical activity on tumor development, growth, and metastasis. Importantly, exercise training may be effective in mitigating the side effects related to anti-cancer treatment, thereby underlining the importance of encouraging cancer patients to engage in moderate-intensity activities. However, the strong need to customize and adapt exercises to a patient’s abilities is apparent. Besides the preventive effects of physically active behavior against the adipokine-stimulated cancer risk, it remains poorly understood how physical activity, through its actions as an adipokine, can actually influence the onset and development of metastases.

Can intermittent fasting be helpful for knee osteoarthritis?

Obesity and Knee Osteoarthritis (KOA) has a proven association. The obese individuals are likely to have early and more severe KOA, and the complications and overall results of surgery are also inferior. Hence, weight reduction is of paramount importance for these individuals. Due to the inability to do intense physical activities, these individuals cannot lose weight and instead perpetually kept gaining weight. Hence, intermittent fasting as a non-operative means of weight reduction is an attractive and viable option. This review article would help sensitize the Orthopaedic Surgeons about fasting in weight reduction and assisting the KOA. Hence, the choice of intermittent fasting should be offered to obese patients with KOA for weight reduction.

Obesity and Energy Balance Considerations in Triple-Negative Breast Cancer

ABSTRACT

Obesity is an increasingly prevalent state of energy imbalance that contributes to breast cancer risk and outcomes. The effects of obesity differ by breast cancer subtype and menopause. While most studies have focused on postmenopausal hormone receptor-positive disease, less is known about the relationship between obesity and triple-negative breast cancer (TNBC). Here we will review the observations linking obesity to TNBC, the socioeconomic disparities that contribute to obesity-related TNBC, and putative biologic mechanisms. Finally, we will consider the impact of obesity on surgical and medical treatment of TNBC and novel strategies to improve energy balance after cancer diagnosis.

Colon Carcinogenesis: The Interplay Between Diet and Gut Microbiota

Colorectal cancer (CRC) incidence increases yearly, and is three to four times higher in developed countries compared to developing countries. The well-known risk factors have been attributed to low physical activity, overweight, obesity, dietary consumption including excessive consumption of red processed meats, alcohol, and low dietary fiber content. There is growing evidence of the interplay between diet and gut microbiota in CRC carcinogenesis. Although there appears to be a direct causal role for gut microbes in the development of CRC in some animal models, the link between diet, gut microbes, and colonic carcinogenesis has been established largely as an association rather than as a cause-and-effect relationship. This is especially true for human studies. As essential dietary factors influence CRC risk, the role of proteins, carbohydrates, fat, and their end products are considered as part of the interplay between diet and gut microbiota. The underlying molecular mechanisms of colon carcinogenesis mediated by gut microbiota are also discussed. Human biological responses such as inflammation, oxidative stress, deoxyribonucleic acid (DNA) damage can all influence dysbiosis and consequently CRC carcinogenesis. Dysbiosis could add to CRC risk by shifting the effect of dietary components toward promoting a colonic neoplasm together with interacting with gut microbiota. It follows that dietary intervention and gut microbiota modulation may play a vital role in reducing CRC risk.

Anthropometry, physical activity and cancer of unknown primary (CUP) risk: Results from the Netherlands cohort study

BACKGROUND

Cancer of Unknown Primary (CUP) is a metastatic disease for which the primary tumour origin could not be identified during life. Few studies have investigated the risk factors associated with this disease. This study investigates anthropometry, physical activity and CUP risk.

METHODS

Data is used from the Netherlands Cohort Study, which includes 120,852 participants aged 55-69 years. All cohort members completed a self-administered questionnaire on cancer risk factors at baseline in 1986. Cancer follow-up was established through record linkage to the Netherlands Cancer Registry and the Dutch Pathology Registry. After a follow-up of 20.3 years, 926 incident CUP cases and 4099 subcohort members were available for case-cohort analyses. Proportional hazards models were used to compute multivariable adjusted hazard ratios (HRs).

RESULTS

We found no associations between height, body mass index (BMI) at baseline, BMI at age 20 years, change in BMI since age 20 years, clothing size (trouser/skirt size), or non-occupational physical activity and CUP risk.

CONCLUSION

Our findings indicate that neither anthropometry nor physical activity are associated with the development of CUP.

Multi-omics Analysis Reveals Adipose-tumor Crosstalk in Patients with Colorectal Cancer

Obesity and obesity-driven cancer rates are continuing to rise worldwide. We hypothesize that adipocyte-colonocyte interactions are a key driver of obesity-associated cancers. To understand the clinical relevance of visceral adipose tissue in advancing tumor growth, we analyzed paired tumor-adjacent visceral adipose, normal mucosa, and colorectal tumor tissues as well as presurgery blood samples from patients with sporadic colorectal cancer. We report that high peroxisome proliferator-activated receptor gamma (PPARG) visceral adipose tissue expression is associated with glycoprotein VI (GPVI) signaling-the major signaling receptor for collagen-as well as fibrosis and adipogenesis pathway signaling in colorectal tumors. These associations were supported by correlations between PPARG visceral adipose tissue expression and circulating levels of plasma 4-hydroxyproline and serum intercellular adhesion molecule 1 (ICAM1), as well as gene set enrichment analysis and joint gene-metabolite pathway results integration that yielded significant enrichment of genes defining epithelial-to-mesenchymal transition-as in fibrosis and metastasis-and genes involved in glycolytic metabolism, confirmed this association. We also reveal that elevated prostaglandin-endoperoxide synthase 2 (PTGS2) colorectal tumor expression is associated with a fibrotic signature in adipose-tumor crosstalk via GPVI signaling and dendritic cell maturation in visceral adipose tissue. Systemic metabolite and biomarker profiling confirmed that high PTGS2 expression in colorectal tumors is significantly associated with higher concentrations of serum amyloid A and glycine, and lower concentrations of sphingomyelin, in patients with colorectal cancer. This multi-omics study suggests that adipose-tumor crosstalk in patients with colorectal cancer is a critical microenvironment interaction that could be therapeutically targeted.See related spotlight by Colacino et al., p. 803.

Lactococcus chungangensis CAU 28 alleviates diet-induced obesity and adipose tissue metabolism in vitro and in mice fed a high-fat diet

Obesity, which has become a major public health problem, can arise from complex dyslipidemia, insulin resistance, and immune responses, among other mechanisms. Some Lactobacillus strains effectively ameliorate obesity; however, the beneficial effects of Lactococcus spp., which are often used as dairy starters, remain unclear. In the present study, we evaluated the efficacy of Lactococcus chungangensis CAU 28 using the 3T3-L1 cell line and obese mice fed a high-fat diet. Overall, administration of Lc. chungangensis CAU 28 effectively resolved obesity associated with weight gain and lipid accumulation. In differentiated 3T3-L1 cells, Lc. chungangensis CAU 28 treatment significantly diminished the total lipid quantity, inhibited triglyceride formation, and prevented the proliferation of adipogenic transcription factors (fatty acid synthase, adiponectin, peroxisome proliferator-activated receptor-gamma, and CCAAT-enhancer-binding protein-α) associated with lipid accumulation. In the obesity mouse model, wherein the intake of Lc. chungangensis CAU 28 effectively reduced body weight gain, along with fat differentiation and accumulation (white fat; abdominal and subcutaneous). Furthermore, Lc. chungangensis CAU 28 increased serum adiponectin levels, decreased serum leptin levels, and effectively regulated adipokine secretion. It also increased the high-density lipoprotein:cholesterol ratio, reduced total cholesterol and triglyceride levels, reduced the low-density lipoprotein:cholesterol ratio, and affected obesity-regulated inflammatory cytokines IL-6, tumor necrosis factor-α, IFN-γ, and IL-1β. Additionally, Lc. chungangensis CAU 28 was associated with an increase in the CD3⁺CD4⁺CD8^- phenotype among obese mice. Thus, the administration of Lc. chungangensis CAU 28 induced antiobesity effects, suggesting potential applications of this species as a supplement for obesity mitigation.

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.

Lipid Metabolism and Cancer Immunotherapy: Immunosuppressive Myeloid Cells at the Crossroad

Cancer progression generates a chronic inflammatory state that dramatically influences hematopoiesis, originating different subsets of immune cells that can exert pro- or anti-tumor roles. Commitment towards one of these opposing phenotypes is driven by inflammatory and metabolic stimuli derived from the tumor-microenvironment (TME). Current immunotherapy protocols are based on the reprogramming of both specific and innate immune responses, in order to boost the intrinsic anti-tumoral activity of both compartments. Growing pre-clinical and clinical evidence highlights the key role of metabolism as a major influence on both immune and clinical responses of cancer patients. Indeed, nutrient competition (i.e., amino acids, glucose, fatty acids) between proliferating cancer cells and immune cells, together with inflammatory mediators, drastically affect the functionality of innate and adaptive immune cells, as well as their functional cross-talk. This review discusses new advances on the complex interplay between cancer-related inflammation, myeloid cell differentiation and lipid metabolism, highlighting the therapeutic potential of metabolic interventions as modulators of anticancer immune responses and catalysts of anticancer immunotherapy.

Japanese mushroom consumption alters the lipid metabolomic profile of high-fat diet-fed mice

Mushrooms are familiar ingredients in Japanese cuisine and large numbers are consumed in Japan. Recently, we reported that the consumption of Japanese mushrooms suppressed the accumulation of visceral fat. The purpose of this study was to examine the alteration of lipid metabolism by Japanese mushrooms consumption in high-fat diet (HFD) mice. Multivariate analysis of serum, liver, adipose tissue, cecal contents, large intestinal and fecal lipids showed differing compositions in the mice that had consumed HFD or HFD supplemented with 3% freeze-dried mushroom mixture (HFMD). There were higher concentrations of diacylglycerol in the adipose tissue, non-esterified fatty acids in the serum, and triacylglycerol in the feces of the HFMD group. These results suggest that mushroom consumption promotes the degradation of lipids in visceral fat and limits the absorption of food lipids. Moreover, the HFMD group demonstrated higher concentrations of phospholipids, some of which contained odd-chain fatty acids. Thus, we speculated that the alteration of lipid metabolism in mice such that mushroom consumption prevent obesity progression, as demonstrated by metabolomic analysis.

The Influence of Sedentary Behavior on Cancer Risk: Epidemiologic Evidence and Potential Molecular Mechanisms

PURPOSE OF REVIEW

Sedentary behavior is an emerging risk factor for several cancers. Here, we review the current epidemiologic evidence on sedentary behavior and cancer risk and summarize potential underlying molecular mechanisms.

RECENT FINDINGS

High compared to low sedentary behavior is associated with a 28-44% increased risk of colon cancer, a 8-17% increased risk of breast cancer, and a 28-36% increased risk of endometrial cancer. For other cancer sites, the current evidence is insufficient, mainly due to sparse numbers of available studies. Potential underlying biologic mechanisms linking prolonged sedentary behavior to increased cancer risk include metabolic dysfunction, alterations in circulating levels of sex hormones, and low-grade systemic chronic inflammation. Prolonged sedentary behavior is positively related to cancers of the colon, breast, and endometrium. For other cancer types, the current evidence is inconclusive. Underlying biological mechanisms are poorly understood and need to be an integral part of future research.

Detection of crown-like structures in breast adipose tissue and clinical outcomes among African-American and White women with breast cancer

BACKGROUND

Crown-like structures in breast adipose tissue (CLS-B), composed of necrotic adipocytes encircled by macrophages, are associated with obesity and hypothesized to worsen breast cancer prognosis; however, data are sparse, particularly in multi-racial populations.

METHODS

We assessed specimens for CLS-B from 174 African-American and 168 White women with stage I-III breast cancer treated by mastectomy. Benign breast tissue from an uninvolved quadrant was immunohistochemically stained for CD68 to determine CLS-B presence and density (per cm2 of adipose tissue). Demographic and lifestyle factors, collected via medical record review, were analyzed for associations with CLS-B using logistic regression. Multivariable Cox proportional hazards models were used to compute hazard ratios (HRs) and 95% confidence intervals (CIs) for associations between CLS-B and overall (OS) or progression-free (PFS) survival.

RESULTS

Detection of any CLS-B was similar between African-American (32%) and White (29%) patients with no evidence of an association between race and CLS-B in multivariable models (OR = 0.82, 95% CI = 0.49-1.36). Detection of CLS-B was associated with obesity (OR = 4.73, 95% CI = 2.48-9.01) and age ≥ 60 years at diagnosis (OR = 1.78, 95% CI = 0.99-3.21). There was some evidence of associations with parity and current smoking status. Detection of CLS-B was not associated with OS (HR = 1.02, 95% CI = 0.55-1.87) or PFS (HR = 0.99, 95% CI = 0.59-1.67).

CONCLUSIONS

Our results show a strong, positive association between BMI and CLS-B in non-tumor tissue similar to previous findings. Detection of CLS-B did not vary by race and was not associated with worse OS or PFS.

[Incidence of Colon Cancer Related to Cigarette Smoking and Alcohol Consumption in Adults with Metabolic Syndrome: Prospective Cohort Study]

PURPOSE

The purpose of this study was to identify the impact of cigarette smoking and alcohol consumption on the incidence of colon cancer in adults with metabolic syndrome.

METHODS

This study employed a longitudinal study design and utilized secondary data drawn from the Korean Genome and Epidemiology Study (KoGES). The data of a sample of 2,327 adults with metabolic syndrome tracked every two years from 2001 to 2014 were used in this study. Statistical data analyses of the frequency, number of cases per 100,000 person-years, log-rank test, Kaplan-Meier curve, and Cox's proportional hazards regression were performed using IBM SPSS statistics version 24.

RESULTS

During the observation period, the number of colon cancer cases was 46, and the total person-years were 252,444. The incidence of colon cancer was higher in current, over 10 pack-year smokers when compared to non-smokers (hazard ratio=3.38, 95% confidence interval=1.09~8.42).

CONCLUSION

Excessive and long-term smoking should be avoided to prevent colon cancer, especially in adults with metabolic syndrome, since it might exacerbate the risk factors of colon cancer. Particularly, health professionals need to provide individualized smoking cessation interventions to those at high risk of colon cancer.

Impact of bariatric surgery on cancer risk reduction

Obesity is second only to tobacco as a preventable cause of cancer in the US. By multifactorial and often additive mechanisms, obesity leads to the development and promotion of 40% of the cancers diagnosed in this country, including post-menopausal breast, endometrial, colorectal, kidney, liver and pancreatic cancers, among others. Though prevention of obesity should be the ultimate goal of thoughtful and effective healthcare practices, it remains a highly prevalent condition, and morbid obesity (BMI ≥40 Kg/m²) can be refractory to lifestyle interventions in many cases. Currently bariatric surgery is an effective treatment strategy for individuals who suffer from morbid obesity or obesity with associated co-morbidities and fail to lose weight under a medically supervised diet and exercise program. The current review addresses seminal studies that have investigated the potential cancer prevention effects of bariatric surgery, demonstrating a positive impact mostly in post-menopausal breast and endometrial cancers. The controversial association between bariatric surgery and increased colorectal cancer (CRC) risk is also recognized and discussed. Finally, while bariatric surgery should not be routinely recommended as a cancer prevention strategy, it has the potential to decrease the risk for certain types of cancers as a collateral beneficial effect.

A Non-canonical Function of BMAL1 Metabolically Limits Obesity-Promoted Triple-Negative Breast Cancer

The epidemiological association between disrupted circadian rhythms and metabolic diseases is implicated in increased risk of human breast cancer and poor therapeutic outcomes. To define a metabolic phenotype and the underlying molecular mechanism, we applied chronic insulin treatment (CIT) to an in vitro model of triple-negative breast cancer to directly address how BMAL1, a key circadian transcription factor, regulates cancer cell respiration and governs tumor progression. At the cellular level, BMAL1 suppresses the flexibility of mitochondrial substrate usage and the pyruvate-dependent mitochondrial respiration induced by CIT. We established an animal model of diet-induced obesity/hyperinsulinemia and observed that BMAL1 functions as a tumor suppressor in obese, but not lean, mice. Downregulation of BMAL1 is associated with higher risk of metastasis in human breast tumors. In summary, loss of BMAL1 in tumors confers advantages to cancer cells in both intrinsic mitochondrial metabolism and extrinsic inflammatory tumor microenvironment during pre-diabetic obesity/hyperinsulinemia.

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Circadian regulator BMAL1 rewires metabolism in a chronic insulin-treated TNBC model

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Pyruvate links BMAL1 to mitochondrial bioenergetics

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BMAL1 suppresses tumor proliferation and metastasis in hyperinsulinemic obese mice

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BMAL1 influences tumor microenvironment in high-fat-diet-fed mice

The BE GONE trial study protocol: a randomized crossover dietary intervention of dry beans targeting the gut microbiome of overweight and obese patients with a history of colorectal polyps or cancer

BACKGROUND

Mouse and human studies support the promise of dry beans to improve metabolic health and to lower cancer risk. In overweight/obese patients with a history of colorectal polyps or cancer, the Beans to Enrich the Gut microbiome vs. Obesity's Negative Effects (BE GONE) trial will test whether and how an increase in the consumption of pre-cooked, canned dry beans within the context of usual diet and lifestyle can enhance the gut landscape to improve metabolic health and reduce cancer risk.

METHODS/DESIGN

This randomized crossover trial is designed to characterize changes in (1) host markers spanning lipid metabolism, inflammation, and obesity-related cancer risk; (2) compositional and functional profiles of the fecal microbiome; and (3) host and microbial metabolites. With each subject serving as their own control, the trial will compare the participant's usual diet with (intervention) and without (control) dry beans. Canned, pre-cooked dry beans are provided to participants and the usual diet continually assessed and monitored. Following a 4-week run-in and equilibration period, each participant provides a total of 5 fasting blood and 6 stool samples over a total period of 16 weeks. The intervention consists of a 2-week ramp-up of dry bean intake to 1 cup/d, which is then continued for an additional 6 weeks. Intra- and inter-individual outcomes are assessed across each crossover period with consideration of the joint or modifying effects of the usual diet and baseline microbiome.

DISCUSSION

The BE GONE trial is evaluating a scalable dietary prevention strategy targeting the gut microbiome of high-risk patients to mitigate the metabolic and inflammatory effects of adiposity that influence colorectal cancer risk, recurrence, and survival. The overarching scientific goal is to further elucidate interactions between diet, the gut microbiome, and host metabolism. Improved understanding of the diet-microbiota interplay and effective means to target these relationships will be key to the future of clinical and public health approaches to cancer and other major diet- and obesity-related diseases.

TRIAL REGISTRATION

This protocol is registered with the U.S. National Institutes of Health trial registry, ClinicalTrials.gov, under the identifier NCT02843425. First posted July 25, 2016; last verified January 25, 2019.

Randomized Phase II Trial of Exercise, Metformin, or Both on Metabolic Biomarkers in Colorectal and Breast Cancer Survivors

Background

Observational data support inverse relationships between exercise or metformin use and disease outcomes in colorectal and breast cancer survivors, although the mechanisms underlying these associations are not well understood.

Methods

In a phase II trial, stage I–III colorectal and breast cancer survivors who completed standard therapy were randomly assigned to structured exercise or metformin or both or neither for 12 weeks. The primary outcome was change in fasting insulin levels; secondary outcomes included changes in other blood-based energetic biomarkers and anthropometric measurements. Analyses used linear mixed models.

Results

In total, 139 patients were randomly assigned; 91 (65%) completed follow-up assessments. Fasting insulin levels statistically significantly decreased in all three intervention arms (−2.47 μU/mL combination arm, −0.08 μU/mL exercise only, −1.16 μU/mL metformin only, + 2.79 μU/mL control arm). Compared with the control arm, all groups experienced statistically significant weight loss between baseline and 12 weeks (−1.8% combination arm, −0.22% exercise only, −1.0% metformin only, +1.55% control). The combination arm also experienced statistically significant improvements in the homeostatic model assessment for insulin resistance (−30.6% combination arm, +61.2% control) and leptin (−42.2% combination arm, −0.8% control), compared with the control arm. The interventions did not change insulin-like growth factor–1 or insulin-like growth factor binding protein–3 measurements as compared with the control arm. Tolerance to metformin limited compliance (approximately 50% of the participants took at least 75% of the planned dosages in both treatment arms).

Conclusions

The combination of exercise and metformin statistically significantly improved insulin and associated metabolic markers, as compared to the control arm, with potential greater effect than either exercise or metformin alone though power limited formal synergy testing. Larger efforts are warranted to determine if such a combined modality intervention can improve outcomes in colorectal and breast cancer survivors.

Risk Factor Analysis for Breast Cancer in Premenopausal and Postmenopausal Women of Punjab, India

OBJECTIVE

Amritsar, the second largest town of agrarian state of Punjab, India reports high number of breast cancer cases every year. The present study investigated the etiology of breast cancer using various obesity indices and other epidemiological factors among breast cancer patients residing in and around Amritsar city.

METHODS

In this case control study, risk factors for breast cancer were analyzed in 542 female subjects: 271 females with breast cancer patients and 271 unrelated healthy females matched for age as control females.

RESULTS

Bivariate analysis for risk factors in cases and controls showed a lower risk (OR=0.65, 95% CI 0.43-0.99, p=0.04) in obese cases with BMI≥25kg/m2 as compared to subjects with normal BMI. Risk factor analysis showed that parameter which provided risk for cancer in postmenopausal women was obesity and in premenopausal women was parity. Postmenopausal women with BMI (overweight: OR=0.39, 95% CI 0.17-0.92, p=0.03; obese: OR= 0.26, 95% CI 0.13-0.52, p=0.00), WC (OR=0.17, 95% CI 0.05-0.52, p=0.00) and WHtR (p=0.02) had highr risk. Premenopausal women with 3 or less than 3 children had a higher risk (OR=5.54, 95 % CI 2.75-11.19, p=0.00) than postmenopausal women when compared to women with more than 3 children. Binary logistic regression analysis revealed that low parity (≤3) substantially increased the risk for breast cancer (OR=4.80, 95% CI 2.34-9.85, p=0.00) in premenopausal women.

CONCLUSION

Obesity, parity associated breast cancer risk and reduced breastfeeding cumulatively predispose the premenopausal women of this region to higher risk of breast cancer.
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World Cancer Research Fund International: Continuous Update Project-systematic literature review and meta-analysis of observational cohort studies on physical activity, sedentary behavior, adiposity, and weight change and breast cancer risk

PURPOSE

The purpose of the present study was to systematically review the complex associations between energy balance-related factors and breast cancer risk, for which previous evidence has suggested different associations in the life course of women and by hormone receptor (HR) status of the tumor.

METHODS

Relevant publications on adulthood physical activity, sedentary behavior, body mass index (BMI), waist and hip circumferences, waist-to-hip ratio, and weight change and pre- and postmenopausal breast cancer risk were identified in PubMed up to 30 April 2017. Random-effects meta-analyses were conducted to summarize the relative risks across studies.

RESULTS

One hundred and twenty-six observational cohort studies comprising over 22,900 premenopausal and 103,000 postmenopausal breast cancer cases were meta-analyzed. Higher physical activity was inversely associated with both pre- and postmenopausal breast cancers, whereas increased sitting time was positively associated with postmenopausal breast cancer. Although higher early adult BMI (ages 18-30 years) was inversely associated with pre- and postmenopausal breast cancers, adult weight gain and greater body adiposity increased breast cancer risk in postmenopausal women, and the increased risk was evident for HR+ but not HR- breast cancers, and among never but not current users of postmenopausal hormones. The evidence was less consistent in premenopausal women. There were no associations with adult weight gain, inverse associations with adult BMI (study baseline) and hip circumference, and non-significant associations with waist circumference and waist-to-hip ratio that were reverted to positive associations on average in studies accounting for BMI. No significant associations were observed for HR-defined premenopausal breast cancers.

CONCLUSION

Better understanding on the impact of these factors on pre- and postmenopausal breast cancers and their subtypes along the life course is needed.

The influence of fasting and energy restricting diets on IGF-1 levels in humans: A systematic review and meta-analysis

BACKGROUND

Fasting and energy restricting diets have a potential means of delaying or preventing the onset of a range of age-related metabolic and neoplastic diseases. Consistently at the centre of this effect appears to be a significant reduction in circulating IGF-1 levels. The aim of the current systematic review and meta-analysis was to determine the influence of fasting and energy restriction on IGF-1 levels in human subjects.

METHODS

A comprehensive systematic search was conducted from onset of the database to February 2019 in Embase, MEDLINE/PubMed, and SCOPUS to identify randomized clinical trials that investigating the impact of fasting or energy restriction circulating IGF-1 levels. Effect size was reported as weighted mean difference (WMD) and 95% confidence intervals (CI) using a random-effects models. Subgroup analysis was performed to identify the probable source of heterogeneity among trials.

RESULTS

Total pooling of fasting and energy restriction randomised controlled trials in WMD analysis revealed no significant effect on circulating IGF-1 levels (WMD: -16.41 ng/ml, 95% CI: -35.88, 3.07). Sub grouped analysis fasting regimens appeared to substantially reduce IGF-1 (WMD: -28.87 ng/ml, 95% CI: -43.69, -14.05, I² = 00%), energy restricting regimens failed to do the same (WMD: -10.98 ng/ml, 95% CI: -33.08, 11.11, I² = 90%). Within this final subgrouping, it was observed that only energy restriction regimens of 50% or greater of normal daily energy intake were capable of significantly reducing IGF-1 levels (WMD: -36.57 ng/ml, 95% CI: -59.19, -13.95, I² = 00%). Finally, a meta regression were noted in which the percentage restriction of daily energy intake inversely correlated with plasma IGF-1 levels (p = 0.04).

CONCLUSION

This study uncovered that fasting significantly reduced levels of IGF-1, while energy restriction diets were successful only when intake was reduced by 50% or more.

Hyperinsulinemia promotes aberrant histone acetylation in triple-negative breast cancer

BACKGROUND

Hyperinsulinemia, the presence of excess insulin relative to glucose in the blood, is considered to be a poor prognostic indicator for patients with triple-negative breast cancer (TNBC). mTOR, a downstream effector of insulin, enhances mitochondrial biogenesis and activity, thereby increasing acetyl-CoA precursors. Increased acetyl-CoA can, in turn, be utilized by nuclear acetyltransferases for histone acetylation, a critical feature of genome regulation. While signaling pathways downstream of insulin have been established for sometime, the effect of insulin on chromatin remains unclear. We hypothesized that hyperinsulinemia-induced metabolic changes lead to genome-wide changes in histone acetylation in TNBC.

RESULTS

MDA-MB-231 cells were xenografted into hyperinsulinemic and wild-type mice. Tumors in the hyperinsulinemic mice displayed elevated levels of histone acetylation compared to tumors in normal insulin conditions. We show that insulin treatment in vitro leads to global increase in chromatin-associated histone acetylation, in particular at H3K9, through the PI3K/AKT/mTOR pathway. Genome-wide analyses revealed that most promoter regions have an increase in histone acetylation upon insulin treatment. In addition, insulin induces higher levels of reactive oxygen species and DNA damage foci in cells.

CONCLUSIONS

These results demonstrate the impact of hyperinsulinemia on altered gene regulation through chromatin and the importance of targeting hyperinsulinemia-induced processes that lead to chromatin dysfunction in TNBC.

Adult weight gain accelerates the onset of breast cancer

PURPOSE

Weight gain in adulthood is a risk factor for breast cancer; however, the impact on age of onset is unknown. The objective of this study was to investigate whether weight gain from early- to mid-adulthood influenced the timing of breast cancer onset.

METHODS

Increase in body mass index (BMI) from lowest adult BMI to BMI at diagnosis and age at which these events occurred were calculated from breast cancer survivors enrolled in a weight loss trial (n = 660). Quartiles (Q) of the average increase in BMI were determined and associations between weight gain and age at disease onset were analyzed using analysis of covariance and spline regression models.

RESULTS

A significant linear trend was observed across the quartiles of BMI change for earlier age at diagnosis [Q1 52.3 (± 0.73), Q2 51.9 (± 0.70), Q3 49.6 (± 0.66), Q4 47.3 (± 0.67), p < 0.0001] after adjusting for potential confounders. In analyses that stratified by tumor subtype and menopausal status, significant linear trends continued to be observed for earlier age at diagnosis across quartiles of BMI for ER ± , PR ± , HER2 + , as well as pre- and postmenopausal status (p-values < 0.001).

CONCLUSIONS

Women who gain excess weight during adulthood are not only at risk for breast cancer, but also may experience earlier onset of disease and reduced cancer-free years.

Global patterns in excess body weight and the associated cancer burden

The prevalence of excess body weight and the associated cancer burden have been rising over the past several decades globally. Between 1975 and 2016, the prevalence of excess body weight in adults-defined as a body mass index (BMI) ≥ 25 kg/m² -increased from nearly 21% in men and 24% in women to approximately 40% in both sexes. Notably, the prevalence of obesity (BMI ≥ 30 kg/m² ) quadrupled in men, from 3% to 12%, and more than doubled in women, from 7% to 16%. This change, combined with population growth, resulted in a more than 6-fold increase in the number of obese adults, from 100 to 671 million. The largest absolute increase in obesity occurred among men and boys in high-income Western countries and among women and girls in Central Asia, the Middle East, and North Africa. The simultaneous rise in excess body weight in almost all countries is thought to be driven largely by changes in the global food system, which promotes energy-dense, nutrient-poor foods, alongside reduced opportunities for physical activity. In 2012, excess body weight accounted for approximately 3.9% of all cancers (544,300 cases) with proportion varying from less than 1% in low-income countries to 7% or 8% in some high-income Western countries and in Middle Eastern and Northern African countries. The attributable burden by sex was higher for women (368,500 cases) than for men (175,800 cases). Given the pandemic proportion of excess body weight in high-income countries and the increasing prevalence in low- and middle-income countries, the global cancer burden attributable to this condition is likely to increase in the future. There is emerging consensus on opportunities for obesity control through the multisectoral coordinated implementation of core policy actions to promote an environment conducive to a healthy diet and active living. The rapid increase in both the prevalence of excess body weight and the associated cancer burden highlights the need for a rejuvenated focus on identifying, implementing, and evaluating interventions to prevent and control excess body weight.

Therapeutic cancer prevention: achievements and ongoing challenges - a focus on breast and colorectal cancer

The constant increase of cancer incidence and the huge costs of new treatments make cancer prevention a crucial goal in order to maintain sustainable public health systems across the world. Carcinogenesis is a multistep process, which allows time for active intervention with natural or synthetic agents to stop or reverse the pathological process. Cancer prevention medicine can be considered to be treatment of premalignant cells or preneoplastic conditions. Clearly such interventions require well‐defined risk classification so that personalized strategies and specific treatments can be applied to cohorts with a documented increased cancer risk, and not to the general population as a whole. Further development of these strategies in an efficient and timely manner requires investment in the discovery and validation of surrogate cancer biomarkers with both prognostic and predictive value to detect and monitor the efficacy of interventions in clinical trials and beyond. In the field of cancer prevention medicine, breast and colon cancer demonstrates the strongest clinical evidence that pharmacological intervention can lower cancer risk. Here, we offer an overview of the major clinical achievements for these cancers and the critical issues to improve implementation and clinical uptake of efficacious therapies, as well as further developments needed in the field of preventive medicine.

Elevated leptin disrupts epithelial polarity and promotes premalignant alterations in the mammary gland

Obesity is a highly prevalent and modifiable breast cancer risk factor. While the role of obesity in fueling breast cancer progression is well established, the mechanisms linking obesity to breast cancer initiation are poorly understood. A hallmark of breast cancer initiation is the disruption of apical polarity in mammary glands. Here we show that mice with diet-induced obesity display mislocalization of Par3, a regulator of cellular junctional complexes defining mammary epithelial polarity. We found that epithelial polarity loss also occurs in a 3D coculture system that combines acini with human mammary adipose tissue, and establish that a paracrine effect of the tissue adipokine leptin causes loss of polarity by overactivation of the PI3K/Akt pathway. Leptin sensitizes non-neoplastic cells to proliferative stimuli, causes mitotic spindle misalignment, and expands the pool of cells with stem/progenitor characteristics, which are early steps for cancer initiation. We also found that normal breast tissue samples with high leptin/adiponectin transcript ratio characteristic of obesity have an altered distribution of apical polarity markers. This effect is associated with increased epithelial cell layers. Our results provide a molecular basis for early alterations in epithelial architecture during obesity-mediated cancer initiation.

Energy oversupply to tissues: a single mechanism possibly underlying multiple cancer risk factors

BACKGROUND AND OBJECTIVES

Several major risk factors for cancer involve vascular oversupply of energy to affected tissues. These include obesity, diabetes and chronic inflammation. Here, we propose a potential mechanistic explanation for the association between energy oversupply and cancer risk, which we call the metabolic cancer suppression hypothesis: We hypothesize that oncogenesis is normally suppressed by organismal physiology that regulates and strictly limits normal energy supply to somatic cells, and that this protection is removed by abnormal oversupply of energy.

METHODOLOGY

We evaluate this hypothesis using a computational model of somatic cell evolution to simulate experimental manipulation of the vascular energy supply to a tissue. The model simulates the evolutionary dynamics of somatic cells during oncogenesis.

RESULTS

In our simulation experiment, we found that under plausible biological assumptions, elevated energy supply to a tissue led to the evolution of elevated energy uptake by somatic cells, leading to the rapid evolution of both defining traits of cancer cells: hyperproliferation, and tissue invasion.

CONCLUSIONS AND IMPLICATIONS

Our results support the hypothesis of metabolic cancer suppression, suggesting that vascular oversupply of energetic resources to somatic cells removes normal energetic limitations on cell proliferation, and that this accelerates cellular evolution toward cancer. Various predictions of this hypothesis are amenable to empirical testing, and have promising implications for translational research toward clinical cancer prevention.