Obesity, insulin resistance, and cancer prognosis: implications for practice for providing care among cancer survivors

Hypertension and hyperglycaemia are positively correlated with local invasion of early cervical cancer

Background

Metabolic disorders are involved in the development of numerous cancers, but their association with the progression of cervical cancer is unclear. This study aims to investigate the association between metabolic disorders and the pathological risk factors and survival in patients with early cervical cancer.

Methods

Patients with FIGO IB1 (2009) primary cervical cancer who underwent radical hysterectomy and systematic pelvic lymph node dissection at our institution from October 2014 to December 2017 were included retrospectively. Clinical data regarding the metabolic syndrome and surgical pathology of the patient were collected. The correlations between metabolic disorders (hypertension, hyperglycemia, and obesity) and clinicopathological characteristics as well as survival after surgery were analyzed.

Results

The study included 246 patients with clinical IB1 cervical cancer, 111 (45.1%) of whom had at least one of the comorbidities of hypertension, obesity, or hyperglycemia. Hypertension was positively correlated with parametrial invasion and poorly differentiated histology; hyperglycemia was positively correlated with stromal invasion; obesity was negatively associated with lymph node metastasis; but arbitrary disorder did not show any correlation with pathologic features. Hypertension was an independent risk factor for parametrial invasion (OR=6.54, 95% CI: 1.60-26.69); hyperglycemia was an independent risk factor for stromal invasion (OR=2.05, 95% CI: 1.07-3.95); and obesity was an independent protective factor for lymph node metastasis (OR=0.07, 95% CI: 0.01-0.60). Moreover, the patients with hypertension had a significantly lower 5-year OS rate (70.0% vs. 95.3%, P<0.0001) and a significantly lower 5-year PFS rate than those without hypertension (70.0% vs. 91.2%, P=0.010).

Conclusion

Hypertension and hyperglycemia are positively associated with local invasion of early cervical cancer, which need to be verified in multi-center, large scale studies.

Obesity-induced thymic involution and cancer risk

Declining thymic functions associated either with old age (i.e., age-related thymic involution), or with acute involution as a result of stress, infectious disease, or cytoreductive therapies (e.g., chemotherapy/radiotherapy), have been associated with cancer development. A key mechanism underlying such increased cancer risk is the thymus-dependent debilitation of adaptive immunity, which is responsible for orchestrating immunoediting mechanisms and tumor immune surveillance. In the past few years, a blooming set of evidence has intriguingly linked obesity with cancer development and progression. The majority of such studies has focused on obesity-driven chronic inflammation, steroid/sex hormone and adipokine production, and hyperinsulinemia, as principal factors affecting the tumor microenvironment and driving the development of primary malignancy. However, experimental observations about the negative impact of obesity on T cell development and maturation have existed for more than half a century. Here, we critically discuss the molecular and cellular mechanisms of obesity-driven thymic involution as a previously underrepresented intermediary pathology leading to cancer development and progression. This knowledge could be especially relevant in the context of childhood obesity, because impaired thymic function in young individuals leads to immune system abnormalities, and predisposes to various pediatric cancers. A thorough understanding behind the molecular and cellular circuitries governing obesity-induced thymic involution could therefore help towards the rationalized development of targeted thymic regeneration strategies for obese individuals at high risk of cancer development.

Imaging modalities for measuring body composition in patients with cancer: opportunities and challenges

Body composition assessment (ie, the measurement of muscle and adiposity) impacts several cancer-related outcomes including treatment-related toxicities, treatment responses, complications, and prognosis. Traditional modalities for body composition measurement include body mass index, body circumference, skinfold thickness, and bioelectrical impedance analysis; advanced imaging modalities include dual energy x-ray absorptiometry, computerized tomography, magnetic resonance imaging, and positron emission tomography. Each modality has its advantages and disadvantages, thus requiring an individualized approach in identifying the most appropriate measure for specific clinical or research situations. Advancements in imaging approaches have led to an abundance of available data, however, the lack of standardized thresholds for classification of abnormal muscle mass or adiposity has been a barrier to adopting these measurements widely in research and clinical care. In this review, we discuss the different modalities in detail and provide guidance on their unique opportunities and challenges.

Expected and paradoxical effects of obesity on cancer treatment response

Obesity, whose prevalence is pandemic and continuing to increase, is a major preventable and modifiable risk factor for diabetes and cardiovascular diseases, as well as for cancer. Furthermore, epidemiological studies have shown that obesity is a negative independent prognostic factor for several oncological outcomes, including overall and cancer-specific survival, for several site-specific cancers as well as for all cancers combined. Yet, a recently growing body of evidence suggests that sometimes overweight and obesity may associate with better outcomes, and that immunotherapy may show improved response among obese patients compared with patients with a normal weight. The so-called 'obesity paradox' has been reported in several advanced cancer as well as in other diseases, albeit the mechanisms behind this unexpected relationship are still not clear. Aim of this review is to explore the expected as well as the paradoxical relationship between obesity and cancer prognosis, with a particular emphasis on the effects of cancer therapies in obese people.

The Role of Obesity in the Development and Management of Gynecologic Cancer

Importance

Endometrial cancer is the most common gynecologic malignancy, with an estimated 54,000 new cases and 10,000 deaths in the United States in 2015. The obesity epidemic directly contributes to the escalating prevalence of chronic diseases, including obesity-related cancers. Patient body weight and nutritional status markedly impact perioperative oncologic care, chemotherapy administration, recurrence risk, and survivorship goals.

Objectives

The objective of this review is to explore the association between obesity and the development, treatment, and survival outcomes of gynecologic cancers.

Evidence Acquisition

A systematic literature review was performed utilizing PubMed and ClinicalTrials.gov.

Conclusions and Relevance

Caring for obese women with gynecologic cancers presents unique challenges. A coordinated multidisciplinary and system effort is required to address the prevention and treatment of obesity, as the sequela of this disease is a clear risk factor for the development of gynecologic malignancy and other comorbidities. Health care providers must be ready to address this worldwide health problem.

Impact of baseline visceral fat accumulation on prognosis in patients with metastatic renal cell carcinoma treated with systemic therapy

The aim of this study was to evaluate the clinical significance of visceral fat accumulation as a prognostic factor in patients with metastatic renal cell carcinoma (mRCC) treated with systemic therapies. A total of 114 patients were retrospectively reviewed. All patients received systemic therapy for mRCC at Keio University hospital in Japan. The intra-abdominal visceral fat area was determined by computed tomography at the umbilical level. The visceral fat accumulation was defined as ≥100 cm². The mean visceral fat area was 107.4 ± 62.8 cm². In the whole cohort, the median follow-up was 29 months. According to the Memorial Sloan Kettering Cancer Center (MSKCC) classification, 27.2% patients were favorable risk, 53.5% were intermediate risk, and 19.3% were poor risk. Visceral fat accumulation correlated with improved progression-free (P = 0.0070) and overall survival (P = 0.0001). On multivariate analysis, visceral fat accumulation (P = 0.0290) and MSKCC classification (P = 0.0085) were independent indices to predict progression-free survival in first-line treatment. In addition, visceral fat accumulation (P = 0.0007) and MSKCC classification (P = 0.0005) independently predicted overall survival. Prognostic grouping using visceral fat accumulation was identified as an independent prognostic marker in patients with mRCC. The addition of visceral fat accumulation improved the prognostic value of MSKCC classification alone in predicting overall survival in patients treated with systemic therapy for mRCC.

Breast cancer survival among young women: a review of the role of modifiable lifestyle factors

Almost 7 % of breast cancers are diagnosed among women age 40 years and younger in Western populations. Clinical outcomes among young women are worse. Early age-of-onset increases the risk of contralateral breast cancer, local and distant recurrence, and subsequent mortality. Breast cancers in young women (BCYW) are more likely to present with triple-negative (TNBC), TP53-positive, and HER-2 over-expressing tumors than among older women. However, despite these known differences in breast cancer outcomes and tumor subtypes, there is limited understanding of the basic biology, epidemiology, and optimal therapeutic strategies for BCYW. Several modifiable lifestyle factors associated with reduced risk of developing breast cancer have also been implicated in improved prognosis among breast cancer survivors of all ages. Given the treatment-related toxicities and the extended window for late effects, long-term lifestyle modifications potentially offer significant benefits to BCYW. In this review, we propose a model identifying three main areas of lifestyle factors (energy imbalance, inflammation, and dietary nutrient adequacy) that may influence survival in BCYW. In addition, we provide a summary of mechanisms of action and a synthesis of previous research on each of these topics.

Cardiopulmonary fitness, adiponectin, chemerin associated fasting insulin level in colorectal cancer patients

PURPOSE

Since circulating level of insulin is associated with colorectal cancer prognosis, it is important to identify factors contributing to fasting insulin level in colorectal cancer patients. The purpose of the current study is to investigate the association of physical fitness, adiponectin, and chemerin levels with circulating level of insulin in colorectal cancer patients.

METHODS

A total of 123 stage II-III colorectal cancer patients who completed standard cancer treatment were recruited. Anthropometric characteristics, fitness measurements, fasting insulin level, homeostasis model assessment of insulin resistance, lipid profiles, and adiponectin and chemerin levels were analyzed.

RESULT

Cardiopulmonary fitness level inversely associated with fasting insulin levels (the least fit (1st tertile): 8.11 ± 0.64, moderately fit (2nd tertile): 6.02 ± 0.63, and highly fit (3rd tertile): 5.58 ± 0.66 μU/ml, unfit vs. moderately fit, p < 0.01; unfit vs. highly fit, p < 0.05) after adjustment for gender, age, stage, and BMI. In addition, fasting adiponectin and chemerin levels were associated with fasting insulin levels after adjustment for gender, age, stage, and BMI. In our combined analyses, participants with high adiponectin and low chemerin levels showed significantly lower fasting insulin levels (4.92 ± 0.75 vs. 8.07 ± 0.80 μU/ml, p < 0.01) compared with participants with low adiponectin and high chemerin levels. Multiple linear regression analysis confirmed that cardiopulmonary fitness and adiponectin levels (β = -0.299, p = 0.002; β = -0.201, p = 0.033) were independently associated with fasting insulin level.

CONCLUSION

Our results suggest that physical fitness and adiponectin and chemerin levels may contribute to circulating levels of insulin. These results suggest that exercise may influence the prognosis of colorectal cancer patients by influencing physical fitness level, circulating levels of adiponectin and chemerin.

Environmental (nongenetic) factors in gynecological cancers: update and future perspectives

Globally, gynecological cancers comprise three of the seven most common female cancers and are responsible for more than 1,000,000 new cases and 500,000 deaths annually. This review summarizes current knowledge regarding the role of environmental factors in gynecological cancer etiology and survival, focusing on those that are potentially amenable to intervention. Strong associations with use of exogenous hormones are countered by opposing risks of breast cancer, thus current hormonal preparations are not an option for prevention. Weight control would reduce risk of endometrial cancer but this and other lifestyle modifications are unlikely to have a major effect on gynecological cancer mortality rates. There is little information regarding the potential for lifestyle changes to improve outcomes for women with gynecological cancer.

Body composition parameters and adipokines levels in relation to bone mineral density in patients with malignant bone tumors after treatment

BACKGROUND

Recent data support the concept that adipokines, which are secreted by fat cells, are important modulators of bone metabolism. The aim of this study was to assess the relationships between body composition parameters, adipokines (leptin, adiponectin) and bone mineral density (BMD) in patients with malignant bone tumors after anticancer therapy.

PROCEDURE

The study included 35 patients (median age 14.8 years) with diagnosed malignant bone tumors treated according to obligatory protocols. Total fat mass, lean mass, bone mineral content (BMC) and BMD measurements were performed after treatment completion by dual energy-ray absorptiometry (DXA). Serum concentrations of leptin, leptin receptor and adiponectin were determined using immunoenzymatic assays. The control group consisted of 28 healthy children (median age 14.3 years).

RESULTS

Patients with bone tumor after chemotherapy had significantly higher fat mass (P < 0.01), increased ratio of fat mass/lean mass (P < 0.001), and a decrease (P < 0.001) in total body and lumbar spine BMD compared with controls. We observed higher serum leptin concentration (P < 0.01) and lower soluble leptin receptor (P < 0.001) and adiponectin (P = 0.01) in patients than in controls. The ratios of leptin/leptin receptor and leptin/adiponectin were about three-fold higher in patients compared with the control group (P = 0.001). We found a significant positive correlation between BMD and body composition and a negative correlation between BMD and adiponectin in the patients group.

CONCLUSIONS

Changes in body composition parameters coexisting with disturbed adipokine levels, especially higher levels of leptin and lower levels of adiponectin, might be associated with bone status in patients treated for malignant bone tumors.

Lifestyle modification in cervical cancer survivors: an ongoing need

OBJECTIVE

With the introduction of multimodality therapy for cervical cancer, many women will be long-term survivors in need of comprehensive surveillance care. Our goals were to evaluate patterns of obesity and smoking in a cohort of cervical cancer survivors and to assess the potential influence of these comorbidities on subsequent follow-up.

METHODS

We reviewed the records of patients treated for invasive cervical cancer at our institution from 2000 to 2003 who had no evidence of disease for 3 or more years. Demographic and clinical data were collected, including smoking history and anthropometric measurements. Body mass index (BMI) was categorized according to World Health Organization criteria. Logistic regression and Wilcoxon rank sum analyses were performed.

RESULTS

Two hundred ninety-eight women had complete follow-up data at 3 years. The median age at diagnosis was 43.5 years (range, 17.6-87.1 years). At diagnosis, 31.9% had a normal BMI, 28.2% were overweight, and 34.6% were obese compared with 31.7%, 21.1%, and 30.2% at 3 years, respectively. Of the 51 women whose BMI categorization changed, 33 (64.7%) had weight gain, and 18 (35.3%) had weight loss. By paired analyses, increase in BMI was significant over the 3-year interval (P < 0.001). Seventy patients actively smoked at diagnosis. Compared with nonsmokers, current smokers had a greater odds of referral to the pain service (odds ratio [OR], 6.56; confidence interval [CI], 6.26-16.43; P < 0.001), physical therapy (OR, 4.74; CI, 1.29-17.36; P = 0.02), and gastroenterology (OR, 2.25; CI, 1.14-4.24; P = 0.02).

CONCLUSIONS

Obesity and smoking are significant comorbidities that may complicate care in cervical cancer survivors. Interventions aimed at modifying these risk factors should be routinely undertaken in this population.

Obesity and non-Hodgkin lymphoma survival in an ethnically diverse population: the Multiethnic Cohort study

PURPOSE

Obesity increases mortality for several malignancies, but for non-Hodgkin lymphoma (NHL), the association between body mass index (BMI) and survival is unclear. We examined the association of pre-diagnostic BMI with overall and NHL-specific survival in the multiethnic cohort (MEC) study of African Americans, Native Hawaiians, Japanese Americans, Latinos, and Caucasians.

METHODS

MEC participants free of NHL at cohort entry and diagnosed with NHL during follow-up were included in the analyses (n = 1,331). BMI was based on self-reported weight and height at cohort entry and after 6.1 years of cohort entry. Cox proportional hazards regression was used to calculate hazard ratios (HR) and 95 % confidence intervals (CI) with BMI as time-varying exposure in relation to all-cause and NHL-specific mortality while adjusting for known confounders.

RESULTS

The mean age at NHL diagnosis was 70.5 (range 45-89) years. After a mean follow-up of 4.3 ± 3.5 years, 667 deaths including 450 NHL-specific deaths occurred. In multivariable models, obese patients (BMI ≥30.0 kg/m(2)) had higher all-cause (HR 1.46, 95 % CI 1.13-1.87) and NHL-specific (HR 1.77, 95 % CI 1.30-2.41) mortality compared with patients with high-normal BMI (22.5-24.9 kg/m(2)). For overweight patients (BMI = 25.0-29.9 kg/m(2)), the respective HRs were 1.21 (95 % CI 0.99-1.49) and 1.36 (95 % CI 1.06-1.75). Cases with low-normal BMI (<22.5 kg/m(2)) experienced a significant 45 % higher all-cause and a 40 % higher NHL-specific mortality. After stratification by NHL type, the adverse effect of BMI was stronger for chronic lymphocytic leukemia/small lymphocytic lymphoma than for diffuse large B cell lymphoma and follicular lymphoma.

CONCLUSIONS

Pre-diagnostic BMI may be a suitable prognostic marker for NHL patients.

Evaluation of epidemiological factors in survival of patients with de novo myelodysplastic syndromes

Myelodysplastic syndromes (MDS) prognosis is currently based solely on clinical parameters. The identification of additional factors associated with MDS outcome could be used to further improve the current scoring system such as the International Prognostic Scoring System (IPSS). The present study evaluates the role of epidemiological markers as predictors of survival for 365 adult de novo MDS patients. Multivariable Cox regression analysis was used to estimate overall survival. Median follow-up time was 22 months. At the time of last follow-up, 271 patients (74.3 %) had died. For all MDS patients, medium-high lifetime occupational agrochemical exposure (HR 1.85, CI 1.19-2.89) remained as an independent predictor of MDS survival. Stratified analysis by gender showed that ≥ 25 pack-years smoked (HR 1.44, CI 1.001-2.09) and medium-high lifetime occupational agrochemical exposure (HR 1.84, CI 1.15-2.97) were independent predictors of MDS survival in men, but not in women. For MDS patients stratified by IPSS categories, ≥ 25 pack-years smoked (HR 1.75, CI 1.005-3.06) was an independent predictor for intermediate 1 IPSS risk group only, and medium-high lifetime occupational agrochemical exposure was associated with increased mortality (HR 4.36, CI 1.20-15.8) in the high IPSS risk group. Smoking and lifetime occupational agrochemical exposure may play a role in MDS survival. Incorporating relevant epidemiological markers with known clinical predictors of outcome may help physician stratify patients and customize treatment strategies to improve the outcome of MDS.

Selectively starving cancer cells through dietary manipulation: methods and clinical implications

As the link between obesity and metabolic syndrome and cancer becomes clearer, the need to determine the optimal way to incorporate dietary manipulation in the treatment of cancer patients becomes increasingly important. Metabolic-based therapies, such as caloric restriction, intermittent fasting and a ketogenic diet, have the ability to decrease the incidence of spontaneous tumors and slow the growth of primary tumors, and may have an effect on distant metastases in animal models. Despite the abundance of preclinical data demonstrating the benefit of dietary modification for cancer, to date there are few clinical trials targeting diet as an intervention for cancer patients. We hypothesize that this may be due, in part, to the fact that several different types of diet modification exist with no clear recommendations regarding the optimal method. This article will delineate three commonly used methods of dietary manipulation to assess the potential of each as a regimen for cancer therapy.

Body mass index, weight change, and survival in non-Hodgkin lymphoma patients in Connecticut women

Evidence is emerging that obesiy and weight gain may affect the prognosis of several types of cancer. We investigated the impact of body mass index (BMI) as well as pre-and postdiagnosis weight changes on non-Hodgkin lymphoma (NHL) prognosis. A cohort of 573 female incident NHL cases diagnosed during 1996-2000 in Connecticut was followed for a median of 7.8 yr. Self-reported height and weight at 3 time points before and after diagnosis were collected. Hazard ratios (HR) and 95% confidence intervals (CI) were estimated using proportional hazard models adjusting for factors believed to be associated with overall survival of NHL. Underweight (BMI < 18.5; HR = 2.84; 95% CI = 1.12-7.15) before diagnosis was associated with poorer survival compared to being normal weight (18.5 ≤ BMI < 25). Prediagnosis weight loss (HR = 1.42; 95% CI = 1.02-1.97) and posttreatment weight loss (HR = 1.98; 95% CI = 1.14-3.45) and weight gain (HR = 1.85; 95% CI = 1.04-3.32) were associated with poorer survival. NHL patients who were underweight, lost weight prediagnosis, or change weight after treatment were found to have a poorer survival.

Obesity and gynecologic cancer etiology and survival

The prevalence of overweight and obesity in the United States and elsewhere has increased dramatically in recent decades. It has long been known that obese women have an increased risk of developing endometrial cancer, but recent studies suggest this association is strongest for the most common low-grade endometrioid endometrial cancers and weaker for the other histologic subtypes. There are insufficient data to assess whether obesity affects endometrial cancer-specific survival or whether the relation with all-cause mortality is similar to that seen in the general population. Recent data suggest obesity also increases risk of ovarian cancer, although it may not influence risk of the high-grade serous cancers that account for the majority of ovarian cancer deaths, and that it is also associated with poorer outcomes. There is currently insufficient evidence to draw any clear conclusions regarding the relation between obesity and risk of/survival from other gynecologic cancers although there are suggestions that obesity may increase risk of cervical cancer, particularly adenocarcinoma, and perhaps vulvar cancer. Possible mechanisms whereby obesity might influence gynecologic cancer risk and survival include: its strong association with endogenous estrogen levels among postmenopausal women, its effects on glucose metabolism, its effects on the wide range of adipocytokines and inflammatory mediators that are produced by adipose tissue and altered in concentration among obese individuals, and its potential effects on patient management, particularly with regard to chemotherapy dosing.

Obesity and ovarian cancer survival: a systematic review and meta-analysis

Studies that have examined the association between obesity and ovarian cancer survival have provided conflicting results. We reviewed and quantitatively summarized existing evidence, exploring potentially important sources of variability, such as the timing of body mass index (BMI) assessment and different cutpoints used to categorize BMI. A systematic search of MEDLINE and EMBASE was conducted to identify original data evaluating the association between obesity and survival in women with ovarian cancer. Adjusted hazard ratios (HR) from studies were pooled using a random-effects model. The meta-analysis of 14 studies showed slightly poorer survival among obese than in non-obese women [pooled HR, 1.17; 95% confidence interval (CI), 1.03-1.34]. This estimate did not vary appreciably when BMI was measured before diagnosis (1.13; 0.95-1.35), at the time of diagnosis (1.13; 0.81-1.57) or at the commencement of chemotherapy (1.12; 0.96-1.31). We found a slightly stronger association in studies that only included women with a BMI ≥ 30 in their "obese" group (1.20) than in studies that also included overweight women (BMI ≥ 25; 1.14). Women with ovarian cancer who are obese appear to have slightly worse survival than non-obese women. However, there is a large amount of inter-study variation, which means that no solid conclusions can be drawn.

Dietary fiber, carbohydrates, glycemic index, and glycemic load in relation to breast cancer prognosis in the HEAL cohort

BACKGROUND

Dietary intake of fiber, carbohydrate, glycemic index (GI), and glycemic load (GL) may influence breast cancer survival, but consistent and convincing evidence is lacking.

METHODS

We investigated associations of dietary fiber, carbohydrates, GI, and GL with breast cancer prognosis among n = 688 stage 0 to IIIA breast cancer survivors in the Health, Eating, Activity, and Lifestyle (HEAL) study. Premenopausal and postmenopausal women from Western Washington State, Los Angeles County, and New Mexico participated. Usual diet was assessed with a food frequency questionnaire. Total mortality, breast cancer mortality, nonfatal recurrence, and second occurrence data were obtained from SEER (Surveillance, Epidemiology, and End Results) registries and medical records. Cox proportional hazards regression estimated multivariate-adjusted hazard ratios and 95% confidence intervals (CI).

RESULTS

During a median of 6.7 years follow-up after diagnosis, n = 106 total deaths, n = 83 breast cancer-specific deaths, and n = 82 nonfatal recurrences were confirmed. We observed an inverse association between fiber intake and mortality. Multivariate-adjusted hazard rate ratios (HRR) comparing high to low intake were 0.53 (95% CI 0.23-1.23) and 0.75 (95% CI 0.43-1.31). A threshold effect was observed whereby no additional benefit was observed for intakes of 9 g/d or more. Fiber intake was suggestively inversely associated with breast cancer-specific mortality (HRR = 0.68, 95% CI 0.27-1.70) and risk of nonfatal recurrence or second occurrence (HRR = 0.68, 95% CI 0.27-1.70), but results were not statistically significant.

CONCLUSION

Dietary fiber was associated with a nonsignificant inverse association with breast cancer events and total mortality. Further studies to assess and confirm this relationship are needed in order to offer effective dietary strategies for breast cancer patients.

IMPACT

Increasing dietary fiber may an effective lifestyle modification strategy for breast cancer survivors.

Energy balance, host-related factors, and cancer progression

Obesity is associated with an increased risk and worsened prognosis for many types of cancer, but the mechanisms underlying the obesity-cancer progression link are poorly understood. Several energy balance-related host factors are known to influence tumor progression and/or treatment responsiveness after cancer develops, and these have been implicated as key contributors to the complex effects of obesity on cancer outcome. These host factors include leptin, adiponectin, steroid hormones, reactive oxygen species associated with inflammation, insulin, insulin-like growth factor-1, and sirtuins. Each of these host factors is considered in this article in the context of energy balance and cancer progression. In addition, future research directions in this field are discussed, including the importance of study designs addressing energy balance across the life course, the development and application of highly relevant animal models, potential roles of cancer stem cells in the response to energy balance modulation, and emerging pharmacologic approaches that target energy balance-related pathways.