Visceral adiposity, insulin resistance and cancer risk

Impact of visceral fat volume and fat density on biochemical outcome after radical prostatectomy and postoperative radiotherapy

BACKGROUND

To assess the predictive value of visceral adipose tissue (VAT) and adipose tissue density after both radical prostatectomy (RP) and adjuvant or salvage external beam radiotherapy (EBRT).

MATERIALS AND METHODS

We randomly selected 201 patients treated with RP and EBRT between 2005 and 2015. Visceral adipose tissue and subcutaneous adipose tissue volumes were manually contoured and corresponding tissue densities in Hounsfield units (HU) calculated. Time to biochemical recurrence (BCR) was calculated using the Kaplan-Meier method and comparisons were made using the log-rank test. Cox regression analysis was done for multivariate analysis.

RESULTS

Median time to BCR or last follow-up was 32 months. In univariate analysis for BCR, VAT volume and fat density were both associated with a better outcome (p=0.025 and p=0.024, respectively) as well as seminal vesicle involvement (p=0.024). Body mass index (BMI) was not predictive of BCR (p=0.32). In a multivariate model including seminal vesicle involvement, both a VAT volume above the median (HR2.5, 95%CI 1.1-5.7, p=0.03) and a VAT density (HR 2.4, 95%CI 1.1-5.1, p=0.028) above the median remained predictive for a better biochemical outcome. Adjusting for BMI did not significantly change the model.

CONCLUSIONS

In both univariate and multivariate analysis, patients with both a larger VAT volume and density had a better biochemical outcome. The interaction between prostate cancer aggressiveness and visceral fat volume and density needs to be further evaluated to provide a better understanding of this disease.

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.

Postoperative excessive gain in visceral adipose tissue as well as body mass index are associated with adverse outcomes of an ileal pouch

BACKGROUND

There are no published studies on the impact of visceral adipose tissue (VAT) change on outcomes of restorative proctocolectomy and ileal pouch-anal anastomosis (IPAA). The aim of this historic cohort study was to evaluate the impact of excessive VAT gain on the outcomes of inflammatory bowel disease (IBD) patients with IPAA.

METHODS

We evaluated all eligible patients with at least two sequential CT scans after pouch construction from our prospectively maintained Pouchitis Registry between 2002 and 2014. The visceral fat area (VFA) was measured on CT images. The study group comprised patients with a significant VAT gain (> 15%), and the control group was those without. The adverse outcomes of the pouch were defined as the new development of chronic pouch inflammation (chronic pouchitis, chronic cuffitis or Crohn's disease of the pouch), anastomotic sinus and the combination of above (the composite adverse outcome) or pouch failure, after the inception CT.

RESULTS

Of 1564 patients in the Registry, 59 (3.8%) with at least 2 CT scans after pouch surgery were included. Twenty-nine patients (49.2%) were in the study group, and 30 (50.8%) were in the control group. The median duration from the inception to the latest CT was 552 (range: 31-2598) days for the entire cohort. We compared the frequency of new chronic pouch inflammation (13.8% vs 3.3%, P = 0.195), new pouch sinus (10.3% vs 0%, P = 0.112), composite adverse pouch outcome (24.1% vs 3.3%, P = 0.026) or pouch failure (10.3% vs 6.7%, P = 0.671) between the two groups. Kaplan-Meier plot for time-to-pouch failure between the pouch patients with or without excessive body mass index (BMI) gain (> 10%) showed statistical difference (P = 0.011). Limited stepwise multivariate analysis showed that excessive VAT gain (odds ratio = 12.608, 95% confidence interval: 1.190-133.538, P = 0.035) was an independent risk factor for the adverse pouch comes.

CONCLUSIONS

In this cohort of ileal pouch patients, excessive VAT gain as well as gain in BMI after pouch construction was found to be associated with poor long-term outcomes.

Place of sodium-glucose cotransporter-2 inhibitors in East Asian subjects with type 2 diabetes mellitus: Insights into the management of Asian phenotype

The burden of type 2 diabetes (T2DM) in East Asia is alarming. Rapid modernization and urbanization have led to major lifestyle changes and a tremendous increase in the prevalence of obesity, metabolic syndrome, and diabetes mellitus. The development of T2DM at a younger age, with lower body mass index, higher visceral adiposity, and more significant pancreatic beta-cell dysfunction compared to Caucasians are factors responsible for the increased prevalence of T2DM in East Asians. Sodium-glucose Cotransporter-2 (SGLT2) inhibitors (canagliflozin, dapaglifozin, empagliflozin, etc.) reduce renal glucose reabsorption, leading to favorable effects on glycemic, blood pressure, and weight control. The insulin-independent mechanism enables their use as monotherapy or combination therapy with insulin and other oral antidiabetic agents. The role of SGLT2 inhibitors in the management of T2DM among East Asians is an interesting area of research, given that East Asians have been proven to be uniquely different from Caucasians. This review provides comprehensive coverage of the available literature not only on the efficacy and safety, but also on the recent cardiovascular and renal outcomes of SGLT2 inhibitors, focusing among East Asians.

The most important questions in cancer research and clinical oncology-Question 2-5. Obesity-related cancers: more questions than answers

Obesity is recognized as the second highest risk factor for cancer. The pathogenic mechanisms underlying tobacco-related cancers are well characterized and effective programs have led to a decline in smoking and related cancers, but there is a global epidemic of obesity without a clear understanding of how obesity causes cancer. Obesity is heterogeneous, and approximately 25% of obese individuals remain healthy (metabolically healthy obese, MHO), so which fat deposition (subcutaneous versus visceral, adipose versus ectopic) is "malignant"? What is the mechanism of carcinogenesis? Is it by metabolic dysregulation or chronic inflammation? Through which chemokines/genes/signaling pathways does adipose tissue influence carcinogenesis? Can selective inhibition of these pathways uncouple obesity from cancers? Do all obesity related cancers (ORCs) share a molecular signature? Are there common (over-lapping) genetic loci that make individuals susceptible to obesity, metabolic syndrome, and cancers? Can we identify precursor lesions of ORCs and will early intervention of high risk individuals alter the natural history? It appears unlikely that the obesity epidemic will be controlled anytime soon; answers to these questions will help to reduce the adverse effect of obesity on human condition.

5-aminolevulinic acid combined with ferrous ion reduces adiposity and improves glucose tolerance in diet-induced obese mice via enhancing mitochondrial function

Background

Mitochondrial dysfunction is associated with obesity and various obesity-associated pathological conditions including glucose intolerance. 5-Aminolevulinic acid (ALA), a precursor of heme metabolites, is a natural amino acid synthesized in the mitochondria, and various types of cytochromes containing heme contribute to aerobic energy metabolism. Thus, ALA might have beneficial effects on the reduction of adiposity and improvement of glucose tolerance through its promotion of heme synthesis. In the present study, we investigated the effects of ALA combined with sodium ferrous citrate (SFC) on obesity and glucose intolerance in diet-induced obese mice.

Methods

We used 20-weeks-old male C57BL/6J diet-induced obesity (DIO) mice that had been fed high-fat diet from 4th week or wild-type C57BL/6J mice. The DIO mice were orally administered ALA combined with SFC (ALA/SFC) for 6 weeks. At the 4th and 5th week during ALA/SFC administration, mice were fasted for 5 h and overnight, respectively and used for oral glucose tolerance test. After the ALA/SFC administration, the plasma glucose levels, weight of white adipose tissue, and expression levels of mitochondrial oxidative phosphorylation (OXPHOS) complexes were examined. Furthermore, the effects of ALA/SFC on lipid content and glucose uptake were examined in vitro.

Results

Oral administration of ALA/SFC for 6 weeks reduced the body weight by about 10% and the weight of white adipose tissues in these animals. In vitro, ALA/SFC reduced lipid content in mouse 3T3-L1 adipocytes in a dose dependent manner, and enhanced glucose uptake in 3T3-L1 adipocytes by 70–90% and rat L6 myoblasts by 30% at 6 h. Additionally, oral administration of ALA/SFC reduced plasma glucose levels and improved glucose tolerance in DIO mice. Furthermore, ALA/SFC enhanced the expression of OXPHOS complexes III, IV, and V by 40–70% in white adipose tissues of DIO mice, improving mitochondrial function.

Conclusions

Our findings indicate that ALA/SFC is effective in the reduction of adiposity and improvement of glucose tolerance, and that the induction of mitochondrial OXPHOS complex III, IV, and V by ALA/SFC might be an essential component of the molecular mechanisms underlying these effects. ALA/SFC might be a useful supplement for obesity and obesity-related metabolic disease such as type 2 diabetes mellitus.

Electronic supplementary material

The online version of this article (doi:10.1186/s40360-016-0108-3) contains supplementary material, which is available to authorized users.

Visceral adiposity and cancer survival: a review of imaging studies

Although obesity is a well-known risk factor for cancer, the association between obesity and cancer survival remains controversial. This is partially due to the inability of conventional obesity measures to directly assess adiposity or adipose tissue distribution. As a metabolic organ, visceral adipose tissue (VAT) secrets a variety of cytokines and cytokine-like factors, potentially affecting cancer survival. The objective of this review was to investigate the influence of imaging-assessed VAT on cancer survival. A total of 22 studies assessing the impact of visceral adiposity on survival were included. Negative associations between VAT and survival were more frequently observed among patients with colorectal (four of six studies) and pancreatic (three of five studies) cancers, compared to higher VAT predicting longer survival in most studies of renal cell carcinoma patients (four of five studies). Methodological limitations, including unstandardised VAT measurement methods, lack of other body composition measurement (i.e. muscle mass), small sample size and heterogeneous cohort characteristics, may explain controversial findings related to the impact of VAT on cancer survival.

Genetic variants in the mTOR pathway and interaction with body size and weight gain on breast cancer risk in African-American and European American women

PURPOSE

Positive energy imbalance and growth factors linked to obesity promote the phosphatidylinositol 3-kinase/AKT/mammalian target of rapamycin (mTOR) pathway. As the obesity-breast cancer associations differ between European American (EA) and African-American (AA) women, we investigated genetic variants in the mTOR pathway and breast cancer risk in these two racial groups.

METHODS

We examined 400 single-nucleotide polymorphisms (SNPs) in 31 mTOR pathway genes in the Women's Circle of Health Study with 1263 incident breast cancers (645 EA, 618 AA) and 1382 controls (641 EA, 741 AA). Multivariable logistic regression was performed separately within racial groups. Effect modification was assessed for measured body size and weight gain since age 20.

RESULTS

In EA women, variants in FRAP1 rs12125777 (intron), PRR5L rs3740958 (synonymous coding), and CDKAL1 rs9368197 (intron) were associated with increased breast cancer risk, while variants in RPTOR rs9900506 (intron) were associated with decreased risk (nominal p-trend for functional and FRAP1 SNPs or p adjusted for correlated test [p ACT] < 0.05). For AA women, variants in RPTOR rs3817293 (intron), PIK3R1 rs7713645 (intron), and CDKAL1 rs9368197 were associated with decreased breast cancer risk. The significance for FRAP1 rs12125777 and RPTOR rs9900506 in EA women did not hold after correction for multiple comparisons. The risk associated with FRAP1 rs12125777 was higher among EAs who had body mass index ≥30 kg/m(2) (odds ratio = 7.69, 95 % CI 2.11-28.0; p-interaction = 0.007) and gained weight ≥35 lb since age 20 (odds ratio = 3.34, 95 % CI 1.42-7.85; p-interaction = 0.021), compared to their counterparts.

CONCLUSIONS

The mTOR pathway may be involved in breast cancer carcinogenesis differently for EA and AA women.

Body weight, fat distribution and colorectal cancer risk: a report from cohort studies of 134255 Chinese men and women

OBJECTIVE

To evaluate the association of body size and fat distribution with risk of colorectal cancer (CRC) in Chinese men and women.

DESIGN

Population-based, prospective cohort study.

SUBJECTS

The analysis included 134 255 Chinese adults enrolled in the Shanghai Women’s Health Study and the Shanghai Men’s Health Study, with an average follow-up of 11.0 and 5.5 years, respectively.

MEASUREMENTS

Waist circumference (WC), body mass index (BMI) and waist-to-hip ratio (WHR) were measured by trained interviewers at baseline. Multivariable Cox models were used to calculate adjusted hazard ratios (HRs) for incident CRC.

RESULTS

A total of 935 incident CRC cases were identified. Both measures of general adiposity (measured by BMI) and central adiposity (measured by WHR and WC) were significantly associated with increased risk of colon cancer in men but not in women. Multivariable adjusted HRs for colon cancer in men in the highest compared with the lowest quintiles were 2.15 (95% CI: 1.35-3.43; P for trend = 0.0006) for BMI, 1.97 (95% CI: 1.19-3.24; P for trend = 0.0004) for WHR and 2.00 (95% CI: 1.21-3.29; P for trend = 0.0002) for WC. The BMI-associated risk was attenuated in analyses stratified by WHR, while the WHR-associated risk remained significant in the high BMI stratum (HR for comparison of extreme tertiles of WHR: 3.38, 95% CI: 1.47-7.75; P for trend =0.0002). None of these anthropometric measures were significantly associated with rectal cancer.

CONCLUSION

Obesity, particularly central obesity, was associated with increased risk of colon cancer in men.

Obesity and cancer: An update of the global impact

In view of the growing global obesity epidemic, this paper reviews the relation between recent trends in body mass index (BMI) and the changing profile of cancer worldwide. By examining seven selected countries, each representing a world region, a pattern of increasing BMI with region and gender-specific diversity is noted: increasing levels of BMI were most pronounced in the Middle East (Saudi Arabia), rather modest in Eastern Asia (India) and generally more rapid in females than in males. This observation translates into a disproportionate distribution of cancer attributable to high levels of BMI, ranging by sex from 4-9% in Saudi Arabia and from 0.2-1.2% in India. Overweight and obesity may also influence cancer outcomes, and hence have a varying impact on cancer survival and death in different world regions. Future challenges in cancer studies exploring the association with overweight and obesity concern the measurement of adiposity and its potentially cumulative effect over the life course. Given the limitations of BMI as an imperfect measure of body fatness, routine anthropometric data collection needs to be extended to develop more informative measures, such as waist circumference in settings where the gold standard tools remain unaffordable. Furthermore, questions surrounding the dose-response and timing of obesity and their associations with cancer remain to be answered. Improved surveillance of health risk factors including obesity as well as the scale and profile of cancer in every country of the world is urgently needed. This will enable the design of cost-effective actions to curb the growing burden of cancer related to excess body weight.

The effect of visceral obesity on clinicopathological features in patients with endometrial cancer: a retrospective analysis of 200 Chinese patients

Background

To assess the effect of visceral adiposity on clinical and pathological characteristics in patients with endometrial cancer.

Methods

A retrospective review of medical documentation was performed in surgically treated endometrial cancer patients from January to November 2015 in our institution. The visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) were measured at the level of umbilicus on single-slice computerized tomography. Visceral adiposity (VAT%) was calculated as VAT/(VAT + SAT).

Results

A total of 200 cases were included in the study. Median age at diagnosis was 54 years old. Most patients presented with early-stage tumor (86.0 % for I + II) and endometrioid histology (90.5 %). Positive lymph node occurred in 11.0 % (22/200) of the patients with the median number of retrieved nodes as 25 (range, 4–56). The entire population had a median body mass index (BMI) of 24.7 kg/m² and median VAT% of 31.89 %. BMI correlated with total adipose tissue (correlation coefficient = 0.667, P < 0.001), but not with VAT% (P = 0.495). Viscerally obese patients tended to be old and post-menopausal (P < 0.001; P = 0.003). Nodal metastasis and extrauterine disease were more commonly reported in patients with high VAT% (6.0 % vs. 16.0 %, P = 0.024; 9.0 % vs. 19.0 %, P = 0.042, respectively). Univariate and multivariate logistic regressions were performed to discern the contribution of variable factors on the lymph node metastasis. Grade (HR = 15.41, 95 % CI = 1.60–148.76; P = 0.018), lympho-vascular invasion (HR = 449.61, 95 % CI = 31.27–6463.93; P < 0.001) and high VAT% (HR = 6.37, 95 % CI = 1.42–28.69; P = 0.016) retained statistical significance for predicting lymph node metastasis.

Conclusions

Viscerally obese patients were more likely to be old and have positive lymph node as well as extrauterine disease. Grade, lympho-vascular invasion presence and visceral adiposity were predictors of nodal disease.

Comparison of anthropometric measurements of adiposity in relation to cancer risk: a systematic review of prospective studies

PURPOSE

In epidemiology, the relationship between increased adiposity and cancer risk has long been recognized. However, whether the association is the same for measures of abdominal or whole body adiposity is unclear. The aim of this systematic review is to compare cancer risk, associated with body mass index (BMI), an indicator of whole body adiposity, with indicators of abdominal adiposity in studies in which these indicators have been directly measured.

METHODS

We conducted a systematic search from 1974 (EMBASE) and 1988 (PubMed) to September 2015 with keywords related to adiposity and cancer. Included studies were limited to cohort studies reporting directly measured anthropometry and performing mutually adjusted analyses.

RESULTS

Thirteen articles were identified, with two reporting on breast cancer, three on colorectal cancer, three on endometrial cancer, two on gastro-oesophageal cancer, two on renal cancer, one on ovarian cancer, one on bladder cancer, one on liver and biliary tract cancer and one on leukaemia. Evidence suggests that abdominal adiposity is a stronger predictor than whole body adiposity for gastro-oesophageal, leukaemia and liver and biliary tract cancer in men and women and for renal cancer in women. Abdominal adiposity was a stronger predictor for bladder and colorectal cancer in women, while only BMI was a predictor in men. In contrast, BMI appears to be a stronger predictor for ovarian cancer. For breast and endometrial cancer, both measures were predictors for cancer risk in postmenopausal women.

CONCLUSIONS

Only few studies used mutually adjusted and measured anthropometric indicators when studying adiposity-cancer associations. Further research investigating cancer risk and adiposity should include more accurate non-invasive indicators of body fat deposition and focus on the understudied cancer types, namely leukaemia, ovarian, bladder and liver and biliary tract cancer.

Visceral Obesity is Associated with Poor Prognosis in Pancreatic Adenocarcinoma

An association between obesity and unfavorable outcomes for various types of malignancy has been established. Nevertheless, the impact of visceral obesity (VO) on outcomes in pancreatic cancer is still unknown and controversial. The aim of this study was to uncover an association between VO and pancreatic cancer outcomes. We retrospectively reviewed 499 patients with pancreatic cancer who were diagnosed and treated in Severance Hospital from January 2006 to December 2011. Compared to the low-VO group (n = 260), the high-VO group (n = 239) was mostly male (68.2% vs. 31.8%, P < 0.001) and was more likely to have current smoking status (29.7% vs. 17.7%, P < 0.001), current alcohol intake status (52.3% vs. 26.4%, P < 0.001) and diabetes mellitus (54.4% vs. 31.9%, P = 0.028). The progression free survival (PFS) and overall survival (OS) were found to be significantly shorter by the Kaplan-Meier method in the high-VO group than in the low-VO group (PFS; P = 0.044, OS: P = 0.013). In addition, the higher percentage of visceral fat was correlated with more lymph node metastasis and shorter OS (P = 0.011 and P = 0.017, respectively). In patients with pancreatic cancer, VO at the time of diagnosis is associated with negative outcomes, such as shorter PFS and OS.

Identification of a Novel Function of Adipocyte Plasma Membrane-Associated Protein (APMAP) in Gestational Diabetes Mellitus by Proteomic Analysis of Omental Adipose Tissue

Gestational diabetes mellitus (GDM) is considered as an early stage of type 2 diabetes mellitus. In this study, we compared demographic and clinical data between six GDM subjects and six normal glucose tolerance (NGT; healthy controls) subjects and found that homeostasis model of assessment for insulin resistance index (HOMA-IR) increased in GDM. Many previous studies demonstrated that omental adipose tissue dysfunction could induce insulin resistance. Thus, to investigate the cause of insulin resistance in GDM, we used label-free proteomics to identify differentially expressed proteins in omental adipose tissues from GDM and NGT subjects (data are available via ProteomeXchange with identifier PXD003095). A total of 3528 proteins were identified, including 66 significantly changed proteins. Adipocyte plasma membrane-associated protein (APMAP, a.k.a. C20orf3), one of the differentially expressed proteins, was down-regulated in GDM omental adipose tissues. Furthermore, mature 3T3-L1 adipocytes were used to simulate omental adipocytes. The inhibition of APMAP expression by RNAi impaired insulin signaling and activated NFκB signaling in these adipocytes. Our study revealed that the down-regulation of APMAP in omental adipose tissue may play an important role in insulin resistance in the pathophysiology of GDM.

Obesity-associated cancer: an immunological perspective

Epidemiological studies have established an association between obesity, insulin resistance, type 2 diabetes and a number of cancer types. Research has focused predominantly on altered endocrine factors, growth factors and signalling pathways, with little known in man about the immune involvement in the relevant pathophysiological processes. Moreover, in an era of exciting new breakthroughs in cancer immunotherapy, there is also a need to study the safety and efficacy of immunotherapeutics in the complex setting of inflammatory-driven obesity-associated cancer. This review addresses key immune cell subsets underpinning obesity-associated inflammation and describes how such immune compartments might be targeted to prevent and treat obesity-associated cancer. We propose that the modulation, metabolism, migration and abundance of pro- and anti-inflammatory cells and tumour-specific T cells might be therapeutically altered to both restore immune balance, alleviating pathological inflammation, and to improve anti-tumour immune responses in obesity-associated cancer.

Obesity and increased risk of esophageal adenocarcinoma

There has been a substantial increase in the incidence of esophageal adenocarcinoma over the past 40 years. Meta-analyses of large prospective cohorts and population-based case-control studies demonstrate consistent associations between obesity and the development of adenocarcinoma of the esophagus and esophago-gastric junction, with an approximate doubling of risk of esophageal adenocarcinoma among patients who are obese, and an almost five-fold increased risk among those with BMI >40 kg/m². The pathologic precursor, specialized intestinal metaplasia in Barrett's esophagus, is also associated with increased adiposity. Epidemiologic evidence suggests that this cancer risk is not solely due to increased gastro-esophageal reflux, and that adipose tissue itself, in particular visceral adipose, may fuel carcinogenesis through the production of adipokines, cytokines, growth factors, and increased inflammation. The robust epidemiologic evidence linking obesity with esophageal adenocarcinoma makes it an exemplar model for investigating the molecular mechanisms underpinning obesity-associated malignant progression, which are discussed in this review.

Obesity-related insulin resistance: implications for the surgical patient

In healthy surgical patients, preoperative fasting and major surgery induce development of insulin resistance (IR). IR can be present in up to 41% of obese patients without diabetes and this can rise in the postoperative period, leading to an increased risk of postoperative complications. Inflammation is implicated in the aetiology of IR. This review examines obesity-associated IR and its implications for the surgical patient. Searches of the Medline and Science Citation Index databases were performed using various key words in combinations with the Boolean operators AND, OR and NOT. Key journals, nutrition and metabolism textbooks and the reference lists of key articles were also hand searched. Adipose tissue has been identified as an active endocrine organ and the chemokines secreted as a result of macrophage infiltration have a role in the pathogenesis of IR. Visceral adipose tissue appears to be the most metabolically active, although results across studies are not consistent. Results from animal and human studies often provide conflicting results, which has rendered the pursuit of a common mechanistic pathway challenging. Obesity-associated IR appears, in part, to be related to inflammatory changes associated with increased adiposity. Postoperatively, the surgical patient is in a proinflammatory state, so this finding has important implications for the obese surgical patient.

Visceral adiposity and colorectal adenomas: dose-response meta-analysis of observational studies

BACKGROUND

Obesity-related hormonal and metabolic perturbations implicated in colorectal carcinogenesis are mainly driven by visceral adipose tissue (VAT) rather than subcutaneous adipose tissue (SAT). Yet, most epidemiologic studies have examined the relationship between excess adiposity and colorectal neoplasia using body mass index (BMI) and waist circumference (WC). Due to the inability of BMI and WC to distinguish VAT from SAT, they are likely to have underestimated the true association.

PATIENTS AND METHODS

We conducted a dose-response meta-analysis to summarize the relationships between VAT and colorectal adenomas and to examine the value of VAT as an independent risk factor beyond BMI, WC, and SAT. PubMed and Embase were searched through September 2014 to identify relevant observational studies. The summary odds ratio (OR) 95% confidence interval (CI) were estimated using a random-effects model.

RESULTS

In linear dose-response meta-analysis, the summary OR for each 25 cm(2) increase in VAT area was 1.13 (95% CI 1.05-1.21; I(2) = 62%; 6 studies; 2776 cases; range of VAT area = 30-228 cm(2)). The dose-response curve suggested no evidence of nonlinearity (Pnon-linearity = 0.37). In meta-analysis comparing the highest versus lowest category of VAT based on 12 studies, a positive association between VAT and adenomas remained statistically significant even after adjustment for BMI, WC, and SAT. In contrast, adjustment for VAT substantially attenuated associations of BMI, WC, and SAT with adenomas. Across the studies, VAT was more strongly associated with advanced adenomas than nonadvanced adenomas.

CONCLUSIONS

VAT may be the underlying mediator of the observed associations of BMI and WC with adenomas, increasing adenoma risk continuously over a wide range of VAT area. Considering that the joint use of BMI and WC better captures VAT than the use of either one, clinicians are recommended to use both BMI and WC to identify those at high risk for colorectal neoplasia.

Adipocyte secreted factors enhance aggressiveness of prostate carcinoma cells

Obesity has been associated with increased incidence and risk of mortality of prostate cancer. One of the proposed mechanisms underlying this risk association is the change in adipokines expression that could promote the development and progression of the prostate tumor cells. The main goal of this study was to evaluate the effect of preadipocyte and adipocyte secretome in the proliferation, migration and invasion of androgen independent prostate carcinoma cells (RM1) and to assess cell proliferation in the presence of the adiposity signals leptin and insulin. RM1 cells were co-cultured in with preadipocytes, adipocytes or cultured in their respective conditioned medium. Cell proliferation was assessed by flow cytometry and XTT viability test. Cell migration was evaluated using a wound healing injury assay of RM1 cells cultured with conditioned media. Cellular invasion of RM1 cells co-cultured with adipocytes and preadipocytes was assessed using matrigel membranes. Preadipocyte conditioned medium was associated with a small increase in RM1 proliferation, while adipocytes conditioned media significantly increased RM1 cell proliferation (p<0.01). Adipocytes also significantly increased the RM1 cells proliferation in co-culture (p <0.01). Cell migration was higher in RM1 cells cultured with preadipocyte and adipocyte conditioned medium. RM1 cell invasion was significantly increased after co-culture with preadipocytes and adipocytes (p <0.05). Insulin also increased significantly the cell proliferation in contrast to leptin, which showed no effect. In conclusion, prostate carcinoma cells seem to be influenced by factors secreted by adipocytes that are able to increase their ability to proliferate, migrate and invade.

Adult weight gain and adiposity-related cancers: a dose-response meta-analysis of prospective observational studies

BACKGROUND

Adiposity, measured by body mass index, is implicated in carcinogenesis. While adult weight gain has diverse advantages over body mass index in measuring adiposity, systematic reviews on adult weight gain in relation to adiposity-related cancers are lacking.

METHODS

PubMed and Embase were searched through September 2014 for prospective observational studies investigating the relationship between adult weight gain and the risk of 10 adiposity-related cancers. Dose-response meta-analyses were performed using a random-effects model to estimate summary relative risk (RR) and 95% confidence interval (CI) for each cancer type. All statistical tests were two-sided.

RESULTS

A total of 50 studies were included. For each 5 kg increase in adult weight gain, the summary relative risk was 1.11 (95% CI = 1.08 to 1.13) for postmenopausal breast cancer among no- or low-hormone replacement therapy (HRT) users, 1.39 (95% CI = 1.29 to 1.49) and 1.09 (95% CI = 1.02 to 1.16) for postmenopausal endometrial cancer among HRT nonusers and users, respectively, 1.13 (95% CI = 1.03 to 1.23) for postmenopausal ovarian cancer among no or low HRT users, 1.09 (95% CI = 1.04 to 1.13) for colon cancer in men. The relative risk of kidney cancer comparing highest and lowest level of adult weight gain was 1.42 (95% CI = 1.11 to 1.81). Adult weight gain was unrelated to cancers of the breast (premenopausal women, postmenopausal HRT users), prostate, colon (women), pancreas, and thyroid. An increase in risk associated with adult weight gain for breast cancer was statistically significantly greater among postmenopausal women (P(heterogeneity) = .001) and HRT nonusers (P(heterogeneity) = .001); that for endometrial cancer was alike among HRT nonusers (P(heterogeneity) = .04).

CONCLUSIONS

Avoiding adult weight gain itself may confer protection against certain types of cancers, particularly among HRT nonusers.

Associations among pericolonic fat, visceral fat, and colorectal polyps on CT colonography

OBJECTIVE

To determine the association between pericolonic fat and colorectal polyps using CT colonography (CTC).

METHODS

A total of 1169 patients who underwent CTC and optical colonoscopy on the same day were assessed. Pericolonic fat was measured on CTC in a band surrounding the colon. Visceral adipose tissue volume was measured at the L2-L3 levels. Student's t-tests, odds ratio, logistic regression, binomial statistics, and weighted kappa were performed to ascertain associations with the incidence of colorectal polyps.

RESULTS

Pericolonic fat volume fractions (PFVF) were 61.5 ± 11.0% versus 58.1 ± 11.5%, 61.6 ± 11.1% versus 58.7 ± 11.5%, and 62.4 ± 10.6% versus 58.8 ± 11.5% for patients with and without any polyps, adenomatous polyps, and hyperplastic polyps, respectively (P<0.0001). Similar trends were observed when examining visceral fat volume fractions (VFVF). When patients were ordered by quintiles of PFVF or VFVF, there were 2.49-, 2.19-, and 2.39-fold increases in odds ratio for the presence of any polyp, adenomatous polyps, or hyperplastic polyps from the first to the fifth quintile for PFVF and 1.92-, 2.00-, and 1.71-fold increases in odds ratio for VFVF. Polyps tended to occur more commonly in parts of the colon that had more PFVF than the spatially adjusted average for patients in the highest quintile of VFVF.

CONCLUSIONS

Pericolonic fat accumulations, like visceral fat, are correlated with an increased risk of adenomatous and hyperplastic polyps.

Adipose tissue, muscle, and function: potential mediators of associations between body weight and mortality in older adults with type 2 diabetes

OBJECTIVE

Studies in type 2 diabetes report both increased mortality for normal weight and no evidence of an obesity paradox. We aimed to examine whether adipose tissue, muscle size, and physical function, which are known to vary by weight, mediate associations between BMI and mortality.

RESEARCH DESIGN AND METHODS

The AGES-Reykjavik cohort comprised participants aged 66-96 years with diabetes defined by fasting glucose, medications, or self-report. BMI was determined from measured height and weight and classified as normal (18.5-24.9 kg/m(2), n = 117), overweight (25.0-29.9 kg/m(2), n = 293, referent group) or obese (≥30.0 kg/m(2), n = 227). Thigh muscle area and intermuscular, visceral, and subcutaneous adipose tissues were assessed with computed tomography. Function was assessed from gait speed and knee extensor strength. Hazard ratios (HRs) and 95% CIs were estimated by Cox proportional hazards regression adjusted for demographics and diabetes-related risk factors.

RESULTS

The median follow-up was 6.66 years, and there were 85, 59, and 44 deaths among normal weight, overweight, and obese participants, respectively. There was no mortality risk for obese participants and an increased risk among normal weight compared with overweight participants (HR 1.72 [95% CI 1.12-2.64]). Associations remained with adjustment for adipose tissues and knee extensor strength; however, mortality risk for normal weight was attenuated following adjustment for thigh muscle (HR 1.36 [95% CI 0.87-2.11]) and gait speed (HR 1.44 [95% CI 0.91-2.27]). Linear regression confirmed with bootstrapping indicated that thigh muscle size mediated 46% of the relationship between normal weight and mortality.

CONCLUSIONS

Normal weight participants had elevated mortality risk compared with overweight participants. This paradoxical association was mediated in part by muscle size.

Visceral fat accumulation is associated with colorectal cancer in postmenopausal women

Background

Obesity is a known risk factor for colorectal cancer (CRC), and emerging data suggest that this association is mediated by visceral fat rather than total body fat. However, there is a lack of studies evaluating the association between visceral fat area and the prevalence of CRC.

Methods

To investigate the relationship between visceral adiposity and prevalence of CRC, data of 497 women diagnosed with CRC and 318 apparently healthy women were analysed and data of well-balanced 191 pairs of women with CRC and healthy women matched based on propensity scores were additionally analysed. Diagnosis of CRC was confirmed by colonoscopy and histology. Metabolic parameters were assessed, along with body composition, using computed tomography.

Results

The median visceral fat area was significantly higher in the CRC group compared with the control group before and after matching. The prevalence of CRC increased significantly with increasing visceral fat tertiles after matching (p for trend <0.01). A multivariate analysis showed that mean visceral fat area of individuals in the 67^th percentile or greater group was associated with an increased prevalence of CRC (adjusted odds ratio: 1.80; 95% confidence interval: 1.12–2.91 before matching and adjusted odds ratio: 2.96; 95% confidence interval: 1.38–6.33) compared with that of individuals in the 33^th percentile or lower group.

Conclusion

Thus, we conclude that visceral fat area is positively associated with the prevalence of CRC. Although we could not determine the causality, visceral adiposity may be associated with the risk of CRC. Further prospective studies are required to determine the benefits of controlling visceral obesity for reducing CRC risk.

Holo-retinol-binding protein and its receptor STRA6 drive oncogenic transformation

Vitamin A, retinol, circulates in blood bound to retinol-binding protein (RBP). At some tissues, RBP is recognized by STRA6, a plasma membrane protein that serves a dual role: it transports retinol from extracellular RBP into cells and it transduces a signaling cascade mediated by the Janus kinase JAK2 and the transcription factors STAT3 and STAT5. We show here that expression of RBP and STRA6 is markedly upregulated in human breast and colon tumors, that holo-RBP/STRA6 signaling promotes oncogenic properties, and that STRA6 expression is critical for tumor formation by colon carcinoma cells in vivo. The holo-RBP/STRA6 pathway also efficiently induces fibroblasts to undergo oncogenic transformation, rendering them highly tumorigenic. These data establish that holo-RBP and its receptor STRA6 are potent oncogenes and suggest that the pathway is a novel target for therapy of some human cancers.

Inflammatory and metabolic biomarkers and risk of liver and biliary tract cancer

Obesity and associated metabolic disorders have been implicated in liver carcinogenesis; however, there are little data on the role of obesity-related biomarkers on liver cancer risk. We studied prospectively the association of inflammatory and metabolic biomarkers with risks of hepatocellular carcinoma (HCC), intrahepatic bile duct (IBD), and gallbladder and biliary tract cancers outside of the liver (GBTC) in a nested case-control study within the European Prospective Investigation into Cancer and Nutrition. Over an average of 7.7 years, 296 participants developed HCC (n=125), GBTC (n=137), or IBD (n=34). Using risk-set sampling, controls were selected in a 2:1 ratio and matched for recruitment center, age, sex, fasting status, and time of blood collection. Baseline serum concentrations of C-reactive protein (CRP), interleukin-6 (IL-6), C-peptide, total high-molecular-weight (HMW) adiponectin, leptin, fetuin-a, and glutamatdehydrogenase (GLDH) were measured, and incidence rate ratios (IRRs) and 95% confidence intervals (CIs) were estimated using conditional logistic regression. After adjustment for lifestyle factors, diabetes, hepatitis infection, and adiposity measures, higher concentrations of CRP, IL-6, C-peptide, and non-HMW adiponectin were associated with higher risk of HCC (IRR per doubling of concentrations=1.22; 95% CI=1.02-1.46; P=0.03; 1.90; 95% CI=1.30-2.77; P=0.001; 2.25; 95% CI=1.43-3.54; P=0.0005; and 2.09; 95% CI=1.19-3.67; P=0.01, respectively). CRP was associated also with risk of GBTC (IRR=1.22; 95% CI=1.05-1.42; P=0.01). GLDH was associated with risks of HCC (IRR=1.62; 95% CI=1.25-2.11; P=0.0003) and IBD (IRR=10.5; 95% CI=2.20-50.90; P=0.003). The continuous net reclassification index was 0.63 for CRP, IL-6, C-peptide, and non-HMW adiponectin and 0.46 for GLDH, indicating good predictive ability of these biomarkers.

CONCLUSION

Elevated levels of biomarkers of inflammation and hyperinsulinemia are associated with a higher risk of HCC, independent of obesity and established liver cancer risk factors.

Resistin: insulin resistance to malignancy

Adipose tissue is recognized as an endocrine organ that secretes bioactive substances known as adipokines. Excess adipose tissue and adipose tissue dysfunction lead to dysregulated adipokine production that can contribute to the development of obesity-related co-morbidities. Among the various adipokines, resistin, which was initially considered as a determinant of the emergence of insulin resistance in obesity, has appeared as an important link between obesity and inflammatory processes. Several experimental and clinical studies have suggested an association between increased resistin levels and severe conditions associated with obesity such as cardiovascular disease and malignancies. In this review, we present the growing body of evidence that human resistin is an inflammatory biomarker and potential mediator of obesity-associated diseases. A common pathway seems to involve the combined alteration of immune and inflammatory processes that favor metabolic disturbances, atherosclerosis and carcinogenesis. The mode of action and the signaling pathways utilized by resistin in its interactions with target cells could involve oxidative and nitrosative stress. Therefore, resistin could function as a key molecule in the complications of obesity development and could potentially be used as a diagnostic and prognostic marker.

Cognitive impairment in older patients with breast cancer before systemic therapy: is there an interaction between cancer and comorbidity?

PURPOSE

To determine if older patients with breast cancer have cognitive impairment before systemic therapy.

PATIENTS AND METHODS

Participants were patients with newly diagnosed nonmetastatic breast cancer and matched friend or community controls age > 60 years without prior systemic treatment, dementia, or neurologic disease. Participants completed surveys and a 55-minute battery of 17 neuropsychological tests. Biospecimens were obtained for APOE genotyping, and clinical data were abstracted. Neuropsychological test scores were standardized using control means and standard deviations (SDs) and grouped into five domain z scores. Cognitive impairment was defined as any domain z score two SDs below or ≥ two z scores 1.5 SDs below the control mean. Multivariable analyses evaluated pretreatment differences considering age, race, education, and site; comparisons between patient cases also controlled for surgery.

RESULTS

The 164 patient cases and 182 controls had similar neuropsychological domain scores. However, among patient cases, those with stage II to III cancers had lower executive function compared with those with stage 0 to I disease, after adjustment (P = .05). The odds of impairment were significantly higher among older, nonwhite, less educated women and those with greater comorbidity, after adjustment. Patient case or control status, anxiety, depression, fatigue, and surgery were not associated with impairment. However, there was an interaction between comorbidity and patient case or control status; comorbidity was strongly associated with impairment among patient cases (adjusted odds ratio, 8.77; 95% CI, 2.06 to 37.4; P = .003) but not among controls (P = .97). Only diabetes and cardiovascular disease were associated with impairment among patient cases.

CONCLUSION

There were no overall differences between patients with breast cancer and controls before systemic treatment, but there may be pretreatment cognitive impairment within subgroups of patient cases with greater tumor or comorbidity burden.

Republished: obesity and colorectal cancer

Excess body weight, as defined by the body mass index (BMI), has been associated with several diseases and includes subjects who are overweight (BMI≥25-29.9 kg/m(2)) or obese (BMI≥30 kg/m(2)). Overweight and obesity constitute the fifth leading risk for overall mortality, accounting for at least 2.8 million adult deaths each year. In addition around 11% of colorectal cancer (CRC) cases have been attributed to overweight and obesity in Europe. Epidemiological data suggest that obesity is associated with a 30-70% increased risk of colon cancer in men, whereas the association is less consistent in women. Similar trends exist for colorectal adenoma, although the risk appears lower. Visceral fat, or abdominal obesity, seems to be of greater concern than subcutaneous fat obesity, and any 1 kg/m(2) increase in BMI confers additional risk (HR 1.03). Obesity might be associated with worse cancer outcomes, such as recurrence of the primary cancer or mortality. Several factors, including reduced sensitivity to antiangiogenic-therapeutic regimens, might explain these differences. Except for wound infection, obesity has no significant impact on surgical procedures. The underlying mechanisms linking obesity to CRC are still a matter of debate, but metabolic syndrome, insulin resistance and modifications in levels of adipocytokines seem to be of great importance. Other biological factors such as the gut microbita or bile acids are emerging. Many questions still remain unanswered: should preventive strategies specifically target obese patients? Is the risk of cancer great enough to propose prophylactic bariatric surgery in certain patients with obesity?

Impact of obesity on postoperative and long-term outcomes in a general surgery population: a retrospective cohort study

BACKGROUND

The obesity paradox has been demonstrated postoperatively in several surgical populations, but only a few studies have reported long-term survival. This study evaluates the presence of the obesity paradox in a general surgery population, reporting both postoperative and long-term survival.

METHODS

This retrospective study included 10,427 patients scheduled for elective, noncardiac surgery. Patients were classified as underweight (body mass index (BMI) < 18.5 kg/m(2)); normal weight (BMI 18.5-24.9 kg/m(2)); overweight (BMI 25.0-29.9 kg/m(2)); obesity class I (BMI 30.0-34.9 kg/m(2)); obesity class II (BMI 35.0-39.9 kg/m(2)); and obesity class III (BMI ≥ 40.0 kg/m(2)). Study endpoints were 30-day postoperative and long-term mortality, including cause-specific mortality. Multivariable analyses were used to evaluate mortality risks for each BMI category.

RESULTS

Within 30 days after surgery, 353 (3.4 %) patients died. Overweight was the only category associated with postoperative mortality, showing improved survival [odds ratio 0.7; 95 % confidence interval (CI) 0.6-0.9]. During the long-term follow-up 4,884 (47 %) patients died. Underweight patients had the highest mortality risk [hazard ratio (HR) 1.4; 95 % CI 1.2-1.6), particularly due to high cancer-related deaths. In contrast, overweight and obese patients demonstrated improved survival (overweight: HR 0.8, 95 % CI 0.8-0.9; obesity class I: HR 0.7, 95 % CI 0.7-0.8; obesity class II: HR 0.7, 95 % CI 0.6-0.9; obesity class III: HR 0.7, 95 % CI 0.5-1.0), mainly because of a strongly reduced risk of cancer-related death.

CONCLUSIONS

In this surgical population the obesity paradox was validated at the long term, mainly because of decreased cancer-related deaths among obese patients.

Visceral adipose tissue: the link with esophageal adenocarcinoma

OBJECTIVE

There is strong evidence for an association between obesity and esophageal adenocarcinoma (EAC). This study investigated the association between directly measured visceral adipose tissue and the risk of EAC.

METHODS

In a case-control setting, we measured visceral adipose tissue in patients with EAC and healthy controls. Visceral adipose tissue was determined by abdominal CT. Exclusion criteria were uninterpretable CT scans and severe comorbidity. Controls were healthy volunteers undergoing screening CT colonography. Cross-sectional areas of visceral and subcutaneous adipose tissues were measured in cm(2) at L3/L4. Values of adipose tissue of EAC patients were extrapolated to stage 0 and compared to controls. The association between visceral adipose tissue and EAC was calculated with least-squares regression, adjusted for age, sex and TNM stage.

RESULTS

We included 175 EAC patients and 251 controls. While body mass index was similar in EAC patients (26.1 kg/m(2)) and controls (26.2 kg/m(2)), visceral adipose tissue was significantly higher in EAC patients at stage 0 than in controls (276 vs. 231 cm(2); p = 0.015). Regarding subcutaneous adipose tissue, there was no difference.

CONCLUSIONS

Patients with EAC have significantly higher visceral adipose tissue than healthy controls. Visceral adipose tissue is a risk factor in the development of EAC and seems to be more important than obesity alone.

Proteomic analysis of adipose tissue: informing diabetes research

Diabetes, one of the most common endocrine diseases worldwide, results from complex pathophysiological mechanisms that are not fully understood. Adipose tissue is considered a major endocrine organ and plays a central role in the development of diabetes. The identification of the adipose tissue-derived factors that contribute to the onset and progression of diabetes will hopefully lead to the development of preventive and therapeutic interventions. Proteomic techniques may be useful tools for this purpose. In the present review, we have summarized the studies conducting adipose tissue proteomics in subjects with diabetes and insulin resistance, and discussed the proteins identified in these studies as candidates to exert important roles in these disorders.

Validation of anthropometric indices of adiposity against whole-body magnetic resonance imaging--a study within the German European Prospective Investigation into Cancer and Nutrition (EPIC) cohorts

Background

In epidemiological studies, measures of body fat generally are obtained through anthropometric indices such as the body mass index (BMI), waist (WC), and hip circumferences (HC). Such indices, however, can only provide estimates of a person’s true body fat content, overall or by adipose compartment, and may have limited accuracy, especially for the visceral adipose compartment (VAT).

Objective

To determine the extent to which different body adipose tissue compartments are adequately predicted by anthropometry, and to identify anthropometric measures alone, or in combination to predict overall adiposity and specific adipose tissue compartments, independently of age and body size (height).

Methods

In a sub-study of 1,192 participants of the German EPIC (European Prospective Investigation into Cancer and Nutrition) cohorts, whole-body MRI was performed to determine adipose and muscle tissue compartments. Additional anthropometric measurements of BMI, WC and HC were taken.

Results

After adjusting for age and height, BMI, WC and HC were better predictors of total body volume (TBV), total adipose tissue (TAT) and subcutaneous adipose tissue (SAT) than for VAT, coronary adipose tissue (CAT) and skeletal muscle tissue (SMT). In both sexes, BMI was the best predictor for TBV (men: r = 0.72 [0.68–0.76], women: r = 0.80 [0.77–0.83]) and SMT (men: r = 0.52 [0.45–0.57], women: r = 0.48 [0.41–0.54]). WC was the best predictor variable for TAT (r = 0.48 [0.41–0.54]), VAT (r = 0.44 [0.37–0.50]) and CAT (r = 0.34 [0.26–0.41]) (men), and for VAT (r = 0.42 [0.35–0.49]) and CAT (r = 0.29 [0.22–0.37]) (women). BMI was the best predictor for TAT (r = 0.49 [0.43–0.55]) (women). HC was the best predictor for SAT (men (r = 0.39 [0.32–0.45]) and women (r = 0.52 [0.46–0.58])).

Conclusions

Especially the volumes of internal body fat compartments are poorly predicted by anthropometry. A possible implication may be that associations of chronic disease risks with the sizes of internal body fat as measured by BMI, WC and HC may be strongly underestimated.

Managing lipid metabolism in proliferating cells: new perspective for metformin usage in cancer therapy

Cancer cells metabolically adapt to undergo cellular proliferation. Lipids, besides their well-known role as energy storage, represent the major building blocks for the synthesis of neo-generated membranes. There is increasing evidence that cancer cells show specific alterations in different aspects of lipid metabolism. The changes of expression and activity of lipid metabolising enzymes are directly regulated by the activity of oncogenic signals. The dependence of tumour cells on the deregulated lipid metabolism suggests that proteins involved in this process could be excellent chemotherapeutic targets for cancer treatment. Due to its rare side effects in non-cancerous cells, metformin has been recently revaluated as a potential anti-tumourigenic drug, which negatively affects lipid biosynthetic pathways. In this review we summarised the emerging molecular events linking the anti-proliferative effect of metformin with lipid metabolism in cancer cells.

The effect of molecular subtype and body mass index on neo-adjuvant chemotherapy in breast cancer patients

The aim of the present study was to analyze the effect of subtype and body mass index (BMI) on neo-adjuvant chemotherapy (NAC) and postoperative prognosis. Two-hundred and forty nine patients who underwent surgery after NAC were included. A multivariate analysis and survival analysis were used to clarify the relationship between BMI, subtype, and NAC. In the logistic regression model, the pCR rate had a significant relationship with the subtype and tumor stage. In the non-pCR group, more overweight patients had significantly a worse disease-free survival (DFS) compared to normal range patients (Log lank test, p < 0.05). In the Cox proportional hazards model, subtype and tumor stage were significantly associated with decreased DFS. In conclusion, patients with the ER (+), HER (-) type and a high BMI had a high risk for recurrence when they achieved non-pCR after NAC.

Triple-negative breast cancer risk in women is defined by the defect of estrogen signaling: preventive and therapeutic implications

Epidemiologic studies strongly support that triple-negative breast cancers (TNBCs) may be distinct entities as compared with estrogen receptor (ER)+ tumors, suggesting that the etiologic factors, clinical characteristics, and therapeutic possibilities may vary by molecular subtypes. Many investigations propose that reproductive factors and exogenous hormone use differently or even quite inversely affect the risk of TNBCs and ER+ cancers. Controversies concerning the exact role of even the same risk factor in TNBC development justify that the biological mechanisms behind the initiation of both TNBCs and non-TNBCs are completely obscure. To arrive at a comprehensive understanding of the etiology of different breast cancer subtypes, we should also reconsider our traditional concepts and beliefs regarding cancer risk factors. Malignancies are multicausal, but the disturbance of proper estrogen signaling seems to be a crucial risk factor for the development of mammary cancers. The grade of defect in metabolic and hormonal equilibrium is directly associated with TNBC risk for women during their whole life. Inverse impact of menopausal status or parity on the development of ER+ and ER− breast cancers may not be possible; these controversial results derive from the misinterpretation of percentage-based statistical evaluations. Exogenous or parity-associated excessive estrogen supply is suppressive against breast cancer, though the lower the ER expression of tumors, the weaker the anticancer capacity. In women, the most important preventive strategy against breast cancers – included TNBCs – is the strict control and maintenance of hormonal equilibrium from early adolescence through the whole lifetime, particularly during the periods of great hormonal changes.

The role of obesity in gastrointestinal cancer: evidence and opinion

There is increasing recognition of the impact of being overweight and obese on the development of cancers at diverse sites including the gastrointestinal tract. Large epidemiological studies indicate that up to 14% of tumours may be related to obesity. Pathophysiological mechanisms underpinning this association are not well understood and so are discussed in this review.

Role of adipokines and cytokines in obesity-associated breast cancer: therapeutic targets

Obesity is the cause of a large proportion of breast cancer incidences and mortality in post-menopausal women. In obese people, elevated levels of various growth factors such as insulin and insulin-like growth factors (IGFs) are found. Elevated insulin level leads to increased secretion of estrogen by binding to the circulating sex hormone binding globulin (SHBG). The increased estrogen-mediated downstream signaling favors breast carcinogenesis. Obesity leads to altered expression profiles of various adipokines and cytokines including leptin, adiponectin, IL-6, TNF-α and IL-1β. The increased levels of leptin and decreased adiponectin secretion are directly associated with breast cancer development. Increased levels of pro-inflammatory cytokines within the tumor microenvironment promote tumor development. Efficacy of available breast cancer drugs against obesity-associated breast cancer is yet to be confirmed. In this review, we will discuss different adipokine- and cytokine-mediated molecular signaling pathways involved in obesity-associated breast cancer, available therapeutic strategies and potential therapeutic targets for obesity-associated breast cancer.

Circulatory estrogen level protects against breast cancer in obese women

Literary data suggest apparently ambiguous interaction between menopausal status and obesity-associated breast cancer risk based on the principle of the carcinogenic capacity of estrogen. Before menopause, breast cancer incidence is relatively low and adiposity is erroneously regarded as a protective factor against this tumor conferred by the obesity associated defective estrogen-synthesis. By contrast, in postmenopausal cases, obesity presents a strong risk factor for breast cancer being mistakenly attributed to the presumed excessive estrogen-production of their adipose-tissue mass. Obesity is associated with dysmetabolism and endangers the healthy equilibrium of sexual hormone-production and regular menstrual cycles in women, which are the prerequisites not only for reproductive capacity but also for somatic health. At the same time, literary data support that anovulatory infertility is a very strong risk for breast cancer in young women either with or without obesity. In the majority of premenopausal women, obesity associated insulin resistance is moderate and may be counteracted by their preserved circulatory estrogen level. Consequently, it is not obesity but rather the still sufficient estrogen-level, which may be protective against breast cancer in young adult females. In obese older women, never using hormone replacement therapy (HRT) the breast cancer risk is high, which is associated with their continuous estrogen loss and increasing insulin-resistance. By contrast, obese postmenopausal women using HRT, have a decreased risk for breast cancer as the protective effect of estrogen-substitution may counteract to their obesity associated systemic alterations. The revealed inverse correlation between circulatory estrogen-level and breast cancer risk in obese women should advance our understanding of breast cancer etiology and promotes primary prevention measures. New patents recommend various methods for the prevention and treatment of obesity-related systemic disorders and the associated breast cancer.

Expression of ADAM28 and IGFBP-3 genes in patients with colorectal cancer - a preliminary report

Adamalisynes (ADAMs) play an important role in inter-membrane interactions, cell adhesion and fusion processes and protein shedding from the cell surface. Many reports indicate that members of the ADAMs family are overexpressed in human cancer. The aim of the present study was to evaluate ADAM28 and Insulin Like Growth Factor Binding Protein-3 (IGFBP-3)) gene expression in colorectal carcinoma tissues with regard to the overweight or obese status of the patients using an oligonucleotide microarray technique. Fresh tissue specimens were obtained from colorectal cancer patients during surgical treatment. Eighteen specimens from tumour and 18 normal tissue specimens from colorectal cancer patients at clinical stages III and IV were analysed. The examined patients were divided into two groups; those with BMI greater than or equal to 25 and those with normal BMI. The control group consisted of 18 specimens of non-neoplastic colon tissues, which were divided between overweight/obese and normal body weight patients. The gene transcriptional activity from the specimens was analysed using an oligonucleotide microarray technique. Microarrays and rinsing and marking solutions were prepared according to the procedure in the Gene Expression Analysis Technical Manual. The following conclusions were made: i) change of ADAM28 and IGFBP-3 genes expression are present in the normal tissue in overweight/obese patients with colorectal cancer only; ii) the observed molecular variability of ADAM28 and IGFBP-3 expression may be an initial process of cancer proliferation; iii) the histopathologically normal surgical margin in this group of patients was not equal to the molecular margin.

Should visceral fat be reduced to increase longevity?

Several epidemiologic studies have implicated visceral fat as a major risk factor for insulin resistance, type 2 diabetes mellitus, cardiovascular disease, stroke, metabolic syndrome and death. Utilizing novel models of visceral obesity, numerous studies have demonstrated that the relationship between visceral fat and longevity is causal while the accrual of subcutaneous fat does not appear to play an important role in the etiology of disease risk. Specific recommended intake levels vary based on a number of factors, including current weight, activity levels, and weight loss goals. It is discussed the need of reducing the visceral fat as a potential treatment strategy to prevent or delay age-related diseases and to increase longevity.

Should visceral fat, strictly linked to hepatic steatosis, be depleted to improve survival?

Numerous epidemiologic studies have implicated abdominal obesity as a major risk factor for insulin resistance, type 2 diabetes mellitus, cardiovascular disease, stroke, metabolic syndrome and its further expression, i.e., nonalcoholic fatty liver disease and death. Using novel models of visceral obesity, several studies have demonstrated that the relationship between visceral fat and longevity is causal, while the accrual of subcutaneous fat does not appear to play an important role in the etiology of disease risk. The need of reducing the visceral fat to improve survival, mainly taking into account the strict link between nonalcoholic fatty liver disease and the coronary artery disease is discussed.

The relationship between visceral obesity and colorectal cancer

SUMMARY The prevalence of obesity continues to rise globally and physicians and healthcare systems have to prepare for rising rates of obesity-associated disease. Aside from cardiovascular disease and diabetes, recent evidence suggests a strong association between obesity and the development of cancer, including colorectal cancer. Using BMI as a marker for obesity, excess body fat is associated with an increased risk of colorectal cancer; however, this relationship appears to be stronger among males and more consistent for colon rather than rectal cancer. Epidemiologic literature evaluating the risk of obesity on colorectal cancer survival using BMI is less consistent. Recent evidence suggests that visceral fat plays a greater role in the development of disease. Current research on the effect of visceral obesity on colorectal cancer outcomes is in its infancy, but may drive a new wave of practice for this ever-growing population of colorectal cancer patients.

Obesity and diabetes: newer concepts in imaging

Quantifying body fat is currently an area of active research. Recent studies have shown that the quantity and location of fat in different compartments have varying clinical significance. This information can now be obtained from computed tomography (CT) or magnetic resonance (MR), and it can inform clinical decision making for patient management. Diabetes patients with insulin resistance and hyperinsulinemia have nonalcoholic fatty liver disease (NAFLD) ranging from steatosis to nonalcoholic steatohepatitis (NASH) and cirrhosis, typically diagnosed by liver biopsy or serum markers. There is now an emerging role of noninvasive imaging tests such as MR imaging or MR spectroscopy or elastography, which can provide quantitative information and have potential to avoid biopsy. Obese patients with diabetes are also at risk for cardiovascular disease and cancer. There is an emerging role for imaging in early detection of not only structural but also functional abnormalities of myocardium at a subclinical stage. Screening for cancer is currently recommended only for breast, colon, prostate, and cervix. Given wider availability and advances in imaging techniques such as positron emission tomography/CT (faster scans with higher resolution and less ionizing radiation) and better understanding of molecular biology and risk-stratification, more and more cancers are being detected in early stages with better clinical outcomes. Concerns related to cost, overdiagnosis, and unnecessary interventions must be addressed before population-based screening for other cancers is recommended. Based on ongoing imaging research, it is expected that it will be possible to provide more precise measurement of body fat and detect cardiovascular disease and cancers earlier in their course.

Visceral obesity and colorectal cancer: are we missing the boat with BMI?

INTRODUCTION

Compared to subcutaneous fat, visceral fat is more metabolically active, leading to chronic inflammation and tumorigenesis. The aim of this study is to describe the effect of visceral obesity on colorectal cancer outcomes using computed tomography (CT) imaging to measure visceral fat.

MATERIALS AND METHODS

We conducted a retrospective chart review of patients who underwent surgical resection for colorectal cancer. Visceral fat volume was measured by preoperative CT scans. Final analysis was performed by stratifying patients based on oncologic stage.

RESULTS

Two hundred nineteen patients met the inclusion criteria, 111 viscerally obese and 108 nonobese. Body mass index (BMI) weakly correlated with visceral fat volume measurements (R (2) = 0.304). Whereas obese patients had no difference in survival when categorizing obesity by BMI, categorizing based on visceral fat volume resulted in significant differences in stage II and stage III patients. In stage II cancer, viscerally obese patients had a nearly threefold decrease in disease-free survival (hazard ratio (HR) = 2.72; 95 % confidence interval (CI) = 1.21, 6.10). In stage III cancer, viscerally obese patients had a longer time to recurrence (HR = 0.39; 95 % CI = 0.16, 0.99).

CONCLUSION

This study shows that viscerally obese patients with stage II colorectal cancer are at higher risk for poor outcomes and should be increasingly considered for adjuvant chemotherapy.

Visceral adiposity in gastrointestinal and hepatic carcinogenesis

There is emerging evidence that the association between obesity and cancer is mediated by visceral rather than generalised body fat. Visceral fat has been directly implicated in the risk and progression of several gastrointestinal cancers including colorectal, oesophageal, pancreatic and hepatocellular carcinomas. Excess visceral adipose tissue induces a state of chronic systemic inflammation and altered metabolic activity that promotes a pro-oncogenic environment. This review examines the evidence linking visceral fat in gastrointestinal and hepatic carcinogenesis and explores our current understanding of the mechanisms underlying this relationship.