Obesity and Prostate Cancer: A Growing Problem: Fig. 1

Obesity and prostate cancer - microenvironmental roles of adipose tissue

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

The altered levels of adiponectin - leptin as predictive biomarkers to estimate the severity of prostate cancer

Introduction and Aim: Prostate is one of the commonest sites of malignancy affecting elderly male population & is increasingly becoming a significant public health issue especially in countries having aging population. We hypothesized that altered levels of adiponectin-leptins may be an underlying connection between incidence of prostate cancer (PCa) and aged matched males.   Materials and Methods: This study was designed to comparatively corelate circulating serum levels of adiponectin & leptin in 160 elderly patients with PCa to their serum levels in 160 healthy controls. The age and body mass index in all groups were dissimilar in case and control. Based on the Gleason score of 7, =7 >7, patients were further subdivided into low, intermediate, high grades of PCa, respectively.    Results: No significant statistical variance was identified in terms of age, Body mass index (BMI), Radom blood glucose, HDL, LDL, triglycerides, total cholesterol, creatinine, and BUN levels within the compared groups. In PCa patients’ group, concentration levels of serum adiponectin were significantly lower, and levels of serum leptin was significantly greater compared to healthy controls (P<0.001). Statistical analysis revealed a significant positive inverse association between PSA and adiponectin levels (r=0.285, P<0.001) and significant association between serum levels of PSA and leptin (r=0.285, P<0.001). Significant statistical correlation was also evident between BMI, PSA, TG, and leptin were whole group. However, there was no significant association observed between adiponectin or leptin level and grade of the disease.   Conclusion: Evaluation of data in our study suggests that patients of PCa exhibit low concentration of serum adiponectin levels and high concentration of leptin levels. Further, this association was independent of histological grading of disease of disease/disease progression as well as other biochemical parameters.

Fatty Acid Signaling Impacts Prostate Cancer Lineage Plasticity in an Autocrine and Paracrine Manner

Prostate cancer (PCa) affects an estimated 250,000 men every year and causes 34,000 deaths annually. A high-fat diet and obesity are associated with PCa progression and mortality. This study's premise was the novel observation of crosstalk between PCa epithelia and cancer-associated fibroblasts (CAF) in response to palmitate-mediated lineage plasticity. We found that cholesterol activated canonical Hedgehog (Hh) signaling by increasing cilium Gli activity in PCa cells, while palmitate activated Hh independent of Gli. Exogenous palmitate activated SOX2, a known mediator of lineage plasticity, in PCa cells cocultured with CAF. Stroma-derived Wnt5a was upregulated in CAF while cocultured with PCa cells and treated with palmitate. Wnt5a knockdown in CAF inhibited Hh and SOX2 expression in PCa cells from cocultures. These findings supported our proposed mechanism of a high-fat diet promoting Hh signaling-mediated transformation within the tumor microenvironment. SOX2 and Wnt5a expression were limited by the CD36 neutralizing antibody. Mice xenografted with PCa epithelia and CAF tumors were fed a high-fat diet, leading to elevated SOX2 expression and lineage plasticity reprogramming compared to mice fed an isocaloric rodent diet. CD36 inhibition with enzalutamide elevated apoptosis by TUNEL, but limited proliferation and SOX2 expression compared to enzalutamide alone. This study revealed a mechanism for a high-fat diet to affect prostate cancer progression. We found that saturated fat induced lineage plasticity reprogramming of PCa by interaction with CAF through Wnt5a and Hh signaling.

Obesity-Modified CD4+ T-Cells Promote an Epithelial-Mesenchymal Transition Phenotype in Prostate Cancer Cells

Obesity is associated with low-grade chronic inflammation, and metabolic dysregulation. Evidence shows that chronic inflammation inhibits protective immunity mediated by CD4+ T cells. Additionally, obesity-induced inflammation affects prostate cancer progression. However, the effect of obesity on CD4+ T-cell- response to prostate cancer is not well understood. To investigate whether obesity induces changes in CD4+ T cell cytokine profile, cytokine expression was measured in splenic CD4+ T-cells from 10-week-old male C57Bl/6 mice exposed to conditioned media (CM) from macrophages grown in sera from obese subjects. Additionally, expression levels of key regulators of Epithelial-Mesenchymal Transition (EMT) were measure in prostate cancer epithelial cells exposed to conditioned media from obesity-modified T-cells. Cell migration and invasion was measured in prostate cancer epithelial cells exposed to CM from obesity-modified CD4+ T-cells. Obesity suppressed the expression of IFNγ and IL-2 in CD4+ T-cells but up-regulated the expression of IL-6. Prostate epithelial cancer cells exposed to conditioned media from obesity-modified T cell increased the expression of EMT markers and showed a higher invasive and migratory capacity.

Metabolically Abnormal Obesity Increases the Risk of Advanced Prostate Cancer in Chinese Patients Undergoing Radical Prostatectomy

Background

To investigate the pathological risk of prostate cancer (PCa) according to the obesity and metabolic status of Chinese patients undergoing radical prostatectomy.

Materials and Methods

We performed a retrospective cross-sectional study of 1016 patients with PCa who underwent radical prostatectomy and whose metabolic status and body mass index were examined. Multivariate logistic regression analysis was performed to examine the relationship between different metabolic obesity phenotypes and the pathological outcomes of PCa.

Results

Among 1016 men, 551 (54.2%), 106 (10.4%), 238 (23.4%), and 121 (11.9%) were assigned to the metabolically healthy and normal weight (MHNW) group, metabolically abnormal but normal weight (MANW) group, metabolically healthy but overweight or obese (MHO) group, and metabolically abnormal and overweight or obese (MAO) group, respectively. Compared with the MHNW group, the MAO group had a significantly greater risk of a higher prostatectomy Gleason score [odds ratio (OR), 1.907; 95% confidence interval (95% CI), 1.144–3.182], pathological stage (OR, 1.606; 95% CI, 1.035–2.493), and seminal vesicle invasion (OR, 1.673; 95% CI, 1.041–2.687). In contrast, the ORs were not increased in the MHO or MANW group. In the context of normal weight, metabolic disorders were associated with lymph node involvement. The metabolic status and body mass index were not associated with extracapsular extension or surgical margins in any of the four groups.

Conclusion

The MAO phenotype is associated with aggressive PCa, including a higher prostatectomy Gleason score, pathological stage, and seminal vesicle invasion and might also be associated with disease progression. Obesity and metabolic disorders act synergistically to increase the pathological risk of PCa.

Effects of Obesity on the Regulation of Macrophage Population in the Prostate Tumor Microenvironment

Obesity is associated with a greater risk of prostate cancer mortality. However, the mechanisms connecting obesity to the progression of prostate cancer remain unknown. This study determined the impact of obesity on macrophage recruitment and tumor-associated macrophage (TAM) polarization in the prostate tumor microenvironment, since a high concentration of TAMs in tumors has been linked to progression in prostate cancer. We utilized an in vitro model in which pre-adipocytes, prostate cancer cells, and macrophages were exposed to sera from obese or nonobese men, or conditioned media generated under obese or nonobese conditions. Matrigel invasion chambers were used to assess macrophage recruitment in vitro, and immunohistochemical analysis evaluated recruitment in a PTEN knockout mouse model. qPCR was used to measure mRNA levels of CCL2, COX-2, IL-10, TGF-beta, VEGF-A, arginase-1, and MMP-9. PGE2 production was measured by ELISA. Obesity increased macrophage and TAM recruitment, and increased mRNA levels of TAM markers in macrophages. Similarly, obese conditions increased CCL2 and COX-2 expression, as well as PGE2 levels in prostate cancer cells. COX-2 inhibition resulted in lower expression of obesity-induced TAM markers. Our data suggest that obesity promotes macrophage infiltration into the prostate tumor microenvironment, and induces TAM polarization through the COX-2/PGE2 pathway.

Insulin Receptor Isoform Variations in Prostate Cancer Cells

Men who develop prostate cancer (PCa) increasingly have one of the co-morbidities associated with a Western lifestyle that are characterized by hyperinsulinemia, hyperglycemia and increased expression of insulin-like growth factors-I (IGF-I) and IGF-II. Each have been associated with poor prognosis and more aggressive cancers that exhibit increased metabolism and increased glucose uptake. The insulin receptor (IR) has two splice isoforms IR-A and IR-B: IR-A has a higher affinity for IGF-II comparable to that for insulin, whereas the IR-B isoform predominantly just binds to insulin. In this study, we assessed alterations in the IR-A and IR-B isoform ratio and associated changes in cell proliferation and migration of PCa cell lines following exposure to altered concentrations of glucose and treatment with IGF-II and insulin. We observed that where IR-B predominated insulin had a greater effect on migration than IGF-II and IGF-II was more effective when IR-A was the main isoform. With regard to proliferation IGF-II was more effective than insulin regardless of which isoform was dominant. We assessed the abundance of the IR isoforms both in vivo and in vitro and observed that the majority of the tissue samples and cell lines expressed more IR-A than IR-B. Alterations in the isoforms in response to changes in their hormonal milieu could have a profound impact on how malignant cells behave and play a role in promoting carcinogenesis. A greater understanding of the mechanisms underlying changes in alternative splicing of the IR may provide additional targets for future cancer therapies.

A review of clinical effects associated with metabolic syndrome and exercise in prostate cancer patients

Androgen deprivation therapy (ADT), a primary treatment for locally advanced or metastatic prostate cancer, is associated with the adverse effects on numerous physiologic parameters, including alterations in cardiometabolic variables that overlap with components of the metabolic syndrome (MetS). As MetS is an established risk factor for cardiovascular mortality and treatment for prostate cancer has been associated with the development of MetS, interventions targeting cardiometabolic factors have been investigated in prostate cancer patients to attenuate the detrimental effects of ADT. Much support exists for exercise interventions in improving MetS variables in insulin-resistant adults, but less evidence is available in men with prostate cancer. Regular exercise, when performed at appropriate intensities and volumes, can elicit improvements in ADT-related adverse effects, including MetS, and contributes to the growing body of literature supporting the role of exercise in cancer survivorship. This review (1) discusses the biologic inter-relationship between prostate cancer, ADT and MetS, (2) evaluates the current literature in support of exercise in targeting MetS and (3) describes the physiological mechanisms by which exercise may favorably alter MetS risk factors in prostate cancer patients on ADT.

Total, free, and complexed prostate-specific antigen levels among US men, 2007-2010

BACKGROUND

Screening for prostate cancer using prostate-specific antigen (PSA) is common. Prostate cancer has been associated with higher total PSA (tPSA), lower free PSA (fPSA), lower percent free PSA (%fPSA), and higher complexed PSA (cPSA).

METHODS

Total, free and complexed PSAs were performed on 3251 men ≥40years in the 2007-2010 National Health and Nutrition Examination Survey. Distributions of the PSA tests were examined by age, race and ethnicity, and body mass index (BMI) groups. Percentages of men at PSA thresholds were examined.

RESULTS

Total PSA geometric mean was 0.96μg/l among men aged ≥40years and increased from 0.74μg/l for men 40-49years, to 1.82μg/l for men 80years and older. Non-Hispanic Whites had lower age-adjusted mean tPSA (1.03μg/l) and cPSA (0.56μg/l) than non-Hispanic Blacks (tPSA 1.25μg/l and cPSA 0.72μg/l). Obese men had lower age-adjusted mean total, free and complexed PSAs (0.94, 0.27, and 0.51μg/l, respectively) than men with normal BMI (tPSA 1.21, fPSA 0.32, and cPSA 0.68μg/l, respectively).

CONCLUSION

Total, free and complexed PSAs increased with age; tPSA and cPSAs were highest in non-Hispanic Blacks; and total, free, and complexed PSAs were lowest in obese men.

HES5 silencing is an early and recurrent change in prostate tumourigenesis

Prostate cancer is the most common cancer in men, resulting in over 10 000 deaths/year in the UK. Sequencing and copy number analysis of primary tumours has revealed heterogeneity within tumours and an absence of recurrent founder mutations, consistent with non-genetic disease initiating events. Using methylation profiling in a series of multi-focal prostate tumours, we identify promoter methylation of the transcription factor HES5 as an early event in prostate tumourigenesis. We confirm that this epigenetic alteration occurs in 86-97% of cases in two independent prostate cancer cohorts (n=49 and n=39 tumour-normal pairs). Treatment of prostate cancer cells with the demethylating agent 5-aza-2'-deoxycytidine increased HES5 expression and downregulated its transcriptional target HES6, consistent with functional silencing of the HES5 gene in prostate cancer. Finally, we identify and test a transcriptional module involving the AR, ERG, HES1 and HES6 and propose a model for the impact of HES5 silencing on tumourigenesis as a starting point for future functional studies.

Long‑term exposure to leptin enhances the growth of prostate cancer cells

Obesity correlates with an increased risk of developing prostate cancer (PCa) and leptin plays an important role in PCa progression. Since leptin is produced by adipocytes, the serum leptin level is higher in obese than in non-obese individuals. However, the effects of leptin remain controversial and unclear. The aim of the present study was to investigate the effect of leptin on PCa cell aggressiveness. Three human PCa cell lines (LNCaP, DU145 and PC-3) were treated with recombinant leptin for 28 days. Cell proliferation, migration, and invasion were estimated using the WST assay, a wound-healing assay, and a BD Matrigel invasion assay, respectively. The mechanism underlying the proliferative effect of leptin was investigated by cell transfections with small interfering RNA (siRNA) against the leptin receptor (ObR) or forkhead box O1 (FOXO1), and by immunocytochemistry. Long-term exposure of PCa cells to leptin enhanced their proliferation, migration and invasion. Leptin increased ObR expression and enhanced Akt phosphorylation constitutively. Leptin also increased the phosphorylation of FOXO1 via PI3K signaling and FOXO1 gene silencing enhanced PCa cell proliferation. Leptin induced the translocation of FOXO1 from the nucleus to the cytoplasm. Furthermore, the PI3K inhibitor, LY294002 suppressed this translocation. These results suggested that leptin regulated the subcellular localization of FOXO1 and induced Akt phosphorylation. Additionally, we revealed that leptin increased the expression of cyclin D1 and decreased the expression of p21 protein. In conclusion, long-term exposure to leptin increased the cell proliferation, migration, and invasion of PCa cells through inactivation of FOXO1. This inactivation resulted from exclusion of FOXO1 from the nucleus and its restriction to the cytoplasm through PI3K/Akt signaling. Our findings contribute to an understanding of the association between obesity and PCa aggressiveness.

NOTCH and PTEN in prostate cancer

Over the past decade, our understanding of the role that Notch-signaling has in tumorigenesis has shifted from leukemogenesis into cancers of solid tumors. Emerging data suggests that in addition to direct effects mediated through the canonical Notch pathway, Notch may participate in epithelial tumor development through regulation of pathways such as PTEN/PI3K/Akt. Prostate cancer is a disease for which PTEN gene expression is especially essential. This review will summarize a role for Notch in prostate development and cancer with an emphasis on how the Notch pathway may intersect with PTEN/PI3K/Akt and mTOR signaling.

Periprostatic adipose tissue from obese prostate cancer patients promotes tumor and endothelial cell proliferation: a functional and MR imaging pilot study

BACKGROUND

Obesity, particularly visceral adiposity, confers a worse prognosis for prostate cancer (PCa) patients, and increasing periprostatic adipose (PPA) tissue thickness or density is positively associated with more aggressive disease. However, the cellular mechanism of this activity remains unclear. Therefore, in this pilot study, we assessed the functional activity of PPA tissue secretions and established a biochemical profile of PPA as compared to subcutaneous adipose (SQA) tissues from lean, overweight and obese PCa patients.

METHODS

Adipose tissues were collected from PCa patients undergoing surgical prostate removal. Tissues were analyzed by histologic and magnetic resonance (MR) techniques. Explant tissue culture secretions were used in proliferation assays on PCa and endothelial cells.

RESULTS

PPA secretions obtained from obese patients were significantly more pro-proliferative in both PCa and endothelial cells as compared to PPA obtained from lean or overweight men and SQA tissues. Consistent with this, PPA microvessel density was increased, and the T2 relaxation time was decreased, compared to SQA tissues, and we observed a modest, inverse correlation between the T2 and tumor stage. Moreover, the ratio of unsaturated to saturated fatty acids, obtained using MR spectroscopy, showed a modest, inverse correlation with Gleason score.

CONCLUSIONS

These pilot data show that PPA stimulates PCa cell proliferation and angiogenesis and that obesity intensifies this activity, thus generating a mechanistic hypothesis to explain the worse prognosis observed in obese PCa patients. Our pilot study also shows that MR technology may be useful in further elucidating the relationship between obesity and PCa progression.

Metabolic syndrome as a peculiar target for management of prostate cancer patients

An interesting and reciprocal association between the metabolic syndrome and prostate cancer has been identified. Metabolic alterations, such as hyperinsulinemia, increased levels of insulin growth factor-1, and insulin resistance could be on the basis of development and progression of many tumors, including prostate cancer, and changes in body composition, in turn, can represent some side effects of androgen deprivation therapy and novel drugs, such as mammalian target of rapamycin inhibitors. This review evaluates this interrelation between metabolic syndrome and prostate tumor scanning in many clinical and preclinical epidemiological studies and describes possible pathogenetic biological mechanisms. Finally, this article discusses feasible clinical implications for the management, prevention, diagnosis, prognosis, and treatment of patients affected by metabolic syndrome and prostate cancer, with particular attention to the metformin action.

The fat side of prostate cancer

Prostate cancer (PCa) metabolism appears to be unique in comparison with other types of solid cancers. Normal prostate cells mainly rely on glucose oxidation to provide precursors for the synthesis and secretion of citrate, resulting in an incomplete Krebs cycle and minimal oxidative phosphorylation for energy production. In contrast, during transformation, PCa cells no longer secrete citrate and they reactivate the Krebs cycle as energy source. Moreover, primary PCas do not show increased aerobic glycolysis and therefore they are not efficiently detectable with (18)F-FDG-PET. However, increased de novo lipid synthesis, strictly intertwined with deregulation in classical oncogenes and oncosuppressors, is an early event of the disease. Up-regulation and increased activity of lipogenic enzymes (including fatty acid synthase and choline kinase) occurs throughout PCa carcinogenesis and correlates with worse prognosis and poor survival. Thus, lipid precursors such as acetate and choline have been successfully used as alternative tracers for PET imaging. Lipid synthesis intermediates and FA catabolism also emerged as important players in PCa maintenance. Finally, epidemiologic studies suggested that systemic metabolic disorders including obesity, metabolic syndrome, and diabetes as well as hypercaloric and fat-rich diets might increase the risk of PCa. However, how metabolic disorders contribute to PCa development and whether dietary lipids and de novo lipids synthesized intra-tumor are differentially metabolized still remains unclear. In this review, we examine the switch in lipid metabolism supporting the development and progression of PCa and we discuss how we can exploit its lipogenic nature for therapeutic and diagnostic purposes. This article is part of a Special Issue entitled Lipid Metabolism in Cancer.

A longitudinal study on engagement with dieting information as a predictor of dieting behavior among adults diagnosed with cancer

OBJECTIVE

This study explores cancer survivors' engagement with information about dieting to control weight from doctors, interpersonal, and media sources and examines whether engagement from these sources impacts subsequent dieting behavior.

METHODS

A total of 1128 respondents diagnosed with colorectal, breast, or prostate cancers were surveyed over three years following their cancer diagnoses. Using weighted logistic regression analyses, the authors predicted the odds of dieting based on earlier information engagement with sources, controlling for dieting in the previous year and confounders.

RESULTS

Participants reported talking with doctors more frequently (37%) than seeking or scanning from interpersonal and media sources about dieting (15-22%). Seeking from interpersonal and media sources, and discussion with physicians, significantly predicted dieting behavior. In addition, discussions with physicians increased the odds of subsequent dieting behavior by 2.32 times (95% CI: 1.50-3.61; p=.002), over and above the effects of other information engagement.

CONCLUSION

Cancer survivors reported engaging with a variety of information sources about dieting. Engagement with doctors and information-seeking from interpersonal or media sources predicted cancer survivors' dieting behavior a year later.

PRACTICE IMPLICATIONS

The results may inform strategies to encourage and empower cancer survivors to engage with information about healthy lifestyle changes for promoting long-term health.

Features of cancer management in obese patients

There is worldwide increased in obesity prevalence and statistical almost half of United-States, including children, could be obese by 2050. Obesity in cancer patients is a major issue in oncology because weight gain and obesity account for approximately 20% of all cancer cases. Indeed, increased obesity is linked with higher risk of various types of cancer and a poorer survival. Although biological mechanisms underlying how obesity causes an increased risk of cancer are suggested, overweight as a putative direct cause of death is still debated. Numerous confounding factors may impact on survival, including comorbidities and imaging limitations. Moreover, difficulties to achieve the standard oncologic care with surgery, chemotherapy and/or radiation may also be concerned. Herein, we examined the specific features and potential adaptation of the cancer management in overweighed patients. Then, we reviewed how implicated molecular pathways may provide new strategies to decrease cancer risk and predict toxicities in an increasingly obese population.

The adipocyte-derived hormone leptin has proliferative actions on androgen-resistant prostate cancer cells linking obesity to advanced stages of prostate cancer

Background. Because obesity may be a risk factor for prostate cancer, we investigated proliferative effects of adipocytes-derived hormone leptin on human prostate cancer cells and assessed the role of mitogen-activated protein kinase (MAPK) signaling pathway in mediating these actions. Material and Methods. Three human prostate cancer cell lines were treated with increasing doses of recombinant leptin. Cell growth was measured under serum-free conditions using a spectrophotometric assay. Further, Western blotting was applied to detect the phosphorylation of an ERK1/2, and a specific inhibitor of MAPK (PD98059; 40 μM) was used. Results. In both androgen-resistant cell lines DU145 and PC-3, cell growth was dose-dependently increased by leptin after 24 hrs and 48 hrs of incubation, whereas leptin's proliferative effects on androgen-sensitive cell line LNCaP was less pronounced. Further, leptin caused dose-dependent ERK1/2 phosphorylation in both androgen-resistant cell lines, and pretreatment of these cells with PD98059 inhibited these responses. Conclusions. Leptin may be a potential link between obesity and risk of progression of prostate cancer. Thus, studies on leptin and obesity association to prostate cancer should differentiate patients according to androgen sensitivity.

Lipids and prostate cancer

The role of lipid metabolism has gained particular interest in prostate cancer research. A large body of literature has outlined the unique upregulation of de novo lipid synthesis in prostate cancer. Concordant with this lipogenic phenotype is a metabolic shift, in which cancer cells use alternative enzymes and pathways to facilitate the production of fatty acids. These newly synthesized lipids may support a number of cellular processes to promote cancer cell proliferation and survival. Hence, de novo lipogenesis is under intense investigation as a therapeutic target. Epidemiologic studies suggest dietary fat may also contribute to prostate cancer; however, whether dietary lipids and de novo synthesized lipids are differentially metabolized remains unclear. Here, we highlight the lipogenic nature of prostate cancer, especially the promotion of de novo lipid synthesis, and the significance of various dietary lipids in prostate cancer development and progression.

The correlation between metabolic syndrome and prostatic diseases

CONTEXT

Metabolic syndrome (MetS), a cluster of several metabolic abnormalities with a high socioeconomic cost, is considered a worldwide epidemic. Recent epidemiologic and clinical data suggest that MetS is involved in the pathogenesis and progression of prostatic diseases such as benign prostatic hyperplasia (BPH) and prostate cancer (PCa).

OBJECTIVE

This review evaluates the available evidence of the role of MetS in BPH and PCa development and progression and discusses possible clinical implications for the management, prevention, and treatment of these diseases.

EVIDENCE ACQUISITION

A National Center for Biotechnology Information (NCBI) PubMed search for relevant articles published between 1995 and September 2011 was performed by combining the following Patient population, Intervention, Comparison, Outcome (PICO) terms: male, metabolic syndrome, prostate, benign prostatic hyperplasia, prostate cancer, prevention, diagnosis, treatment, and prognosis. Additional references were obtained from the reference list of full-text manuscripts.

EVIDENCE SYNTHESIS

MetS is a complex, highly prevalent disorder and a worldwide epidemic. Central obesity, insulin resistance, dyslipidemia, and hypertension are the main components of MetS. Notwithstanding all the attempts made to correctly define MetS, a major problem related to most definitions remains the applicability to different populations and ethnic groups. Although there is growing evidence of the association of MetS with the initiation and clinical progression of BPH and PCa, molecular mechanisms and effects on treatment efficacy remain unclear. Further research is required to better understand the role of MetS in BPH and PCa.

CONCLUSIONS

Data from the peer-reviewed literature suggest an association of MetS with BPH and PCa, although the evidence for a causal relationship remains missing. MetS should be considered a new domain in basic and clinical research in patients with prostatic disorders.

Metabolic alterations and targeted therapies in prostate cancer

Cancer cells synthesize de novo large amounts of fatty acids and cholesterol, irrespective of the circulating lipid levels and benefit from this increased lipid synthesis in terms of growth advantage, self-survival and drug resistance. Key lipogenic alterations that commonly occur in prostate cancer include over-expression of the enzyme fatty acid synthase (FASN) and deregulation of the 5-AMP-activated protein kinase (AMPK). FASN is a key metabolic enzyme that catalyses the synthesis of palmitate from the condensation of malonyl-CoA and acetyl-CoA de novo and plays a central role in energy homeostasis, by converting excess carbon intake into fatty acids for storage. AMPK functions as a central metabolic switch that governs glucose and lipid metabolism. Recent interest has focused on the potential of targeting metabolic pathways that may be altered during prostate tumorigenesis and progression. Several small molecule inhibitors of FASN have now been described or in development for therapeutic use; in addition, drugs that directly or indirectly induce AMPK activation have potential benefit in prostate cancer prevention and treatment.

Disease and host characteristics as predictors of time to first bone metastasis and death in men with progressive castration-resistant nonmetastatic prostate cancer

BACKGROUND

The natural history of castration-resistant nonmetastatic prostate cancer is poorly defined.

METHODS

The authors used data from 331 subjects in the placebo group of a randomized controlled trial to evaluate the relations of disease and host characteristics with time to first bone metastases in men with prostate cancer, rising prostate-specific antigen (PSA) despite androgen deprivation therapy, and no radiographic evidence of metastases. Relations between baseline covariates and clinical outcomes were assessed by Cox proportional hazard analyses. Covariates in the model were age, body mass index, prior prostatectomy, prior orchiectomy, Gleason score, performance status, PSA, urinary N-telopeptide, bone alkaline phosphatase, albumin, lactate dehydrogenase, and hemoglobin.

RESULTS

At 2 years, 46% of subjects had developed bone metastases, and 20% had died. Median bone metastasis-free survival was 25 months. In multivariate analyses, baseline PSA ≥ 13.1 ng/mL was associated with shorter overall survival (relative risk [RR], 2.34; 95% confidence interval [CI], 1.71-3.21; P < .0001), time to first bone metastasis (RR, 1.98; 95% CI, 1.43-2.74; P < .0001), and bone metastasis-free survival (RR, 1.98; 95% CI, 1.45-2.70; P < .0001). PSA velocity was significantly associated with overall and bone metastasis-free survival. Other covariates were not consistently associated with clinical outcomes.

CONCLUSIONS

In men with progressive castration-resistant prostate cancer and no detectable metastases, baseline PSA was significantly associated with time to first bone metastasis, bone metastasis-free survival, and overall survival. Other disease and host characteristics, including body mass index and bone turnover markers, were not consistently associated with clinical outcomes.

Prostate cancer gene expression signature of patients with high body mass index

The goal of this study was to evaluate prostate cancer gene expression signatures associated with elevated body mass index (BMI). Global gene expression profiles of prostate tumor cells and matching normal epithelial cells were compared between patients with features of normal- and high BMI at the time of radical prostatectomy. Knowledge-based analyses revealed an association of high BMI with altered levels of lipid metabolism and cholesterol homeostasis genes, such as stearoyl-CoA desaturase 1 (SCD1) and insulin-induced gene 1 (INSIG1), respectively, in prostate tumor cells. These genes were connected to known pathways of tumorigenesis revealed by the v-maf (musculoaponeurotic fibrosarcoma) oncogene homolog (MAF), notch receptor ligand, jagged 1 (JAG1), and the alanyl aminopeptidase (ANPEP/CD13) genes. This study highlighted that SCD1, a known target of statins, may play a mechanistic role in the recently noted beneficial effects of statin treatment in reducing biochemical recurrence of prostate cancer. An additional finding of our study is that some of the obesity related genes were upregulated in tumor-matched normal cells within the high BMI group, when compared to normal cells within the normal BMI cohort.

New strategies in prostate cancer: targeting lipogenic pathways and the energy sensor AMPK

Although the role of metabolic syndrome (MS) and a high fat diet in prostate cancer (PCa) risk is still a matter of intense debate, it is becoming increasingly clear that obesity can cause perturbations in metabolic pathways that contribute to the pathogenesis and progression of PCa. Moreover, prostate epithelial cells per se undergo a series of metabolic changes, including an increase in de novo lipogenesis, during the process of tumor formation. These metabolic alterations, at both the cellular and organismal levels, are intertwined with genetic aberrations necessary for neoplastic transformation. Thus, altered metabolism is currently subject to intense research efforts and might provide preventative and therapeutic opportunities, as well as a platform for biomarker development. In this article, we review evidence that the metabolic sensor 5'-AMP-activated protein kinase (AMPK), which physiologically integrates nutritional and hormonal signals and regulates cell survival and growth-related metabolic pathways to preserve intracellular ATP levels, represents a link between energy homeostasis and cancer. Thus, when AMPK is not activated, as in the setting of MS and obesity, systemic metabolic alterations permissive to the development of PCa are allowed to proceed unchecked. Hence, the use of AMPK activators and inhibitors of key lipogenic enzymes may represent a promising therapeutic strategy for PCa.

A systematic review of the effect of diet in prostate cancer prevention and treatment

Dietary therapy has been proposed as a cost effective and noninvasive means of reducing the risk of prostate cancer (PC) and its progression. There is a large volume of published studies describing the role of diet in the prevention and treatment of PC. This article systematically reviews the data for dietary-based therapy in the prevention of PC, as well as in the management of patients with PC, aiming to provide clarity surrounding the role of diet in preventing and treating PC. Although conclusive evidence is limited, the current data are indicative that a diet low in fat, high in vegetables and fruits, and avoiding high energy intake, excessive meat, excessive dairy products and calcium intake, is possibly effective in preventing PC. However, caution must be taken to ensure that members of the public do not take excessive amounts of dietary supplements because there may be adverse affects associated with their over consumption. The dietary recommendations for patients diagnosed with PC are similar to those aiming to reduce their risk of PC.

Biological mediators of effect of diet and stress reduction on prostate cancer

BACKGROUND

A 6-month pilot intervention trial was conducted to determine whether adoption of a plant-based diet, reinforced by stress reduction, could reduce the rate of prostate-specific antigen (PSA) increase, a marker of disease progression, in asymptomatic, hormonally untreated patients experiencing consistently increasing PSA levels after surgery or radiation.

METHODS

A pre-post design was used to examine (1) the effect of intervention on potential mediators of disease progression, including body composition and weight-related biomarkers (sex steroid hormones and cytokines), and (2) whether changes in these variables were associated with change in rate of PSA increase. The baseline rate of PSA increase (from the time of posttreatment recurrence to the start of intervention) was ascertained from medical records. Body composition and biomarkers were assessed at baseline (prior to intervention), during the intervention (3 months), and at the end of the intervention (6 months). Changes in body composition and biomarkers were determined and compared with rates of PSA increase over the corresponding time intervals.

RESULTS

There was a significant reduction in waist-to-hip ratio (P=.03) and increase in circulating sex hormone binding globulin (P=.04). The rate of PSA increase decreased from the preintervention period (PSA slope=0.059) to the period from 0 to 3 months (PSA slope=0.002, P<.01) and increased slightly, although not significantly, from 0 to 3 months to the period from 3 to 6 months (0.029, P=.43).

CONCLUSIONS

Adoption of a plant-based diet and stress reduction may reduce central adiposity and improve the hormonal milieu in patients with recurrent PC. Changes in the rate of increase in PSA were in the same direction as changes in waist-to-hip ratio and opposite those of sex hormone binding globulin, raising the possibility that the effect of the intervention may have been mediated, in part, by these variables.

Insulin receptor expression by human prostate cancers

BACKGROUND

Although recent laboratory and population studies suggest that prostate cancer may be responsive to insulin, there is a gap in knowledge concerning the expression of insulin receptors on benign or malignant prostate tissue.

METHODS

We immunostained 644 cores on tissue microarrays prepared from 29 prostate tissue samples without malignancies, 78 Gleason grade 3 cancers, 21 Gleason grade 4 cancers and 33 Gleason grade 5 cancers with antibodies against the insulin-like growth factor I receptor and the insulin receptor.

RESULTS

We observed immunoreactivity with both antibodies, which implies the presence of hybrid receptors as well as IGF-I receptors and insulin receptors. Insulin receptor staining intensity was significantly (P < 0.001) higher on malignant than benign prostate epithelial cells. Analysis of information from public gene expression databases confirmed that co-expression of insulin receptor mRNA and IGF-I receptor mRNA is common in prostate cancer specimens. RT-PCR methods provided evidence for the presence of mRNA for both IR-A and IR-B insulin receptor isoforms.

CONCLUSION

These observations document the presence of insulin receptors on primary human prostate cancers. The findings are relevant not only to ongoing clinical trials of drug candidates that target IGF-I and/or insulin receptors, but also to the hypothesis that obesity-associated hyperinsulinemia mediates the adverse effect of obesity on prostate cancer prognosis.

Mitogenic and anti-apoptotic actions of adipocyte-derived hormone leptin in prostate cancer cells

OBJECTIVE

To investigate the proliferative and anti-apoptotic effects of leptin on human prostate cancer cells, and the role of related signalling pathways in mediating these actions, as obesity is a possible risk factor for prostate cancer and leptin, an adipocyte-derived hormone, has mitogenic action in various cell types.

MATERIALS AND METHODS

Two human prostate cancer cell lines, DU145 and PC-3, were treated with leptin (5-100 ng/mL) for up to 48 h. Under serum-free conditions, cell proliferation was measured using a colorimetric tetrazolium assay and apoptosis by an enzyme-linked immunosorbent assay measuring cell death. Also, the phosphorylation of ERK1/2 and Akt was detected by Western blotting, and specific inhibitors of mitogen-activated protein kinase (MAPK) (PD98059; 40 microm) and phosphatidylinositol 3-kinase (PI3-K, LY294002; 40 microm) were used to evaluate the role of these signalling pathways.

RESULTS

Leptin dose-dependently increased the cell number in both cell lines for up to 48 h of incubation, the mean (sem) percentage of the control being 189 (4.3)% for DU145 and 173 (7.5)% for PC-3 (100 ng/mL leptin, 48 h; P < 0.01). Leptin also significantly reduced the number of apoptotic cells after 24 h of treatment, dose-dependently caused ERK1/2 and Akt phosphorylation; pretreatment with inhibitors of MAPK and PI3-K inhibited these responses.

CONCLUSION

These results show that chronic increases in leptin might enhance the growth of prostate cancer via the MAPK and PI3-K pathways. Further studies are needed to investigate whether the ability of leptin to stimulate mitogenic/anti-apoptotic signal transduction pathways could represent a target for anticancer drug discovery.

Association of diet-induced hyperinsulinemia with accelerated growth of prostate cancer (LNCaP) xenografts

BACKGROUND

Prior research suggested that energy balance and fat intake influence prostate cancer progression, but the influence of dietary carbohydrate on prostate cancer progression has not been well characterized. We hypothesized that hyperinsulinemia resulting from high intake of refined carbohydrates would lead to more rapid growth of tumors in the murine LNCaP xenograft model of prostate cancer.

METHODS

Athymic mice were injected subcutaneously with LNCaP human prostate cancer cells and, when tumors were palpable, were randomly assigned (n = 20 per group) to high carbohydrate-high fat or low carbohydrate-high fat diets. Body weight and tumor volume were measured weekly. After 9 weeks, serum levels of insulin and insulin-like growth factor 1 (IGF-1) were measured by enzyme immunoassay. AKT activation and the levels of the insulin receptor in tumor cells were determined by immunoblotting. The in vitro growth response of LNCaP cells to serum from mice in the two treatment groups was measured based on tetrazolium compound reduction. All statistical tests were two-sided.

RESULTS

After 9 weeks on the experimental diets, mice on the high carbohydrate-high fat diet were heavier (mean body weight of mice on the high carbohydrate-high fat diet = 34 g versus 29.1 g on the low carbohydrate-high fat diet, difference = 4.9 g, 95% CI = 3.8 to 6.0 g; P = .003), experienced increased tumor growth (mean tumor volume in mice on high carbohydrate-high fat diet = 1695 versus 980 mm3 on low carbohydrate-high fat diet, difference = 715 mm3, 95% CI = 608 to 822 mm3; P<.001), and experienced a statistically significant increase in serum insulin and IGF-1 levels. Tumors from mice on the high carbohydrate-high fat diet had higher levels of activated AKT and modestly higher insulin receptor levels than tumors from mice on the low carbohydrate-high fat diet. Serum from mice on the high carbohydrate-high fat diet was more mitogenic for LNCaP cells in vitro than serum from mice fed the low carbohydrate-high fat diet.

CONCLUSION

A diet high in refined carbohydrates is associated with increased tumor growth and with activation of signaling pathways distal to the insulin receptor in a murine model of prostate cancer.

Obesity as a predictor of biochemical recurrence and survival after radiation therapy for prostate cancer

OBJECTIVE

Obesity has been demonstrated to predict biochemical progression in men undergoing radical prostatectomy for prostate adenocarcinoma, and is associated with a higher risk of biochemical and clinical relapse after radiation therapy (RT). We evaluated if obesity, determined by body mass index (BMI), is associated with adverse disease characteristics, pre-treatment serum testosterone, biochemical disease free survival (bDFS), disease-specific survival (DSS), or overall survival (OS) in patients undergoing radical external beam radiation therapy for prostate cancer.

PATIENTS AND METHODS

A cohort of 706 patients with localized prostate adenocarcinoma treated with RT between 1993 and 2001 were categorized as obese (BMI > or = 30 kg/m(2)), overweight (BMI 25-29.9 kg/m(2)) or normal (BMI < 25 kg/m(2)). The association between BMI, disease characteristics, and progression were evaluated by Chi-square and ANOVA tests, Kaplan-Meier survival analysis, and Cox regression analysis.

RESULTS

195 patients (27.6%) were normal weight, 358 (50.7%) were overweight and 153 (21.7%) were obese. Obese men had lower serum testosterone levels than overweight and normal-weight men (means 12.8, 14.1, and 15.7 nmol/L, respectively; p < 0.001). The BMI groups did not differ in Gleason score, pretreatment PSA, or stage. On multivariate analysis, BMI group was predictive of reduced bDFS (p = 0.02) and DSS (p = 0.008), with a trend toward reduced OS (p = 0.062).

CONCLUSION

Obesity was associated with lower serum testosterone levels but not with adverse pretreatment pathological features. Obese men have a higher risk of biochemical recurrence and prostate-cancer specific death after RT.

Obesity and sex steroids during gonadotropin-releasing hormone agonist treatment for prostate cancer

PURPOSE

To evaluate effects of obesity on sex steroid levels during treatment with a gonadotropin-releasing hormone agonist in men with prostate cancer.

EXPERIMENTAL DESIGN

Forty-nine hormone-naïve men with recurrent or locally advanced prostate cancer were included in the analyses. All subjects were treated with leuprolide 3-month depot for 48 weeks. Serum levels of estradiol, sex hormone-binding globulin, total testosterone, and free testosterone were assessed at baseline, 24 weeks, and 48 weeks. Subjects were categorized by body mass index (BMI) and percent body fat.

RESULTS

Pretreatment serum sex hormone-binding globulin and total testosterone levels were significantly lower in overweight and obese men than in men with normal BMI. In the overall study population, mean serum testosterone concentrations decreased from 372 +/- 18 ng/dL at baseline to 13 +/- 1 ng/dL at week 48 (P < 0.001). Free testosterone decreased from 6.75 +/- 0.33 ng/dL at baseline to 0.21 +/- 0.02 ng/dL at week 48 (P < 0.001). During treatment with leuprolide, obese men had significantly higher total and free testosterone levels than men with normal BMI. Compared with normal men, total and free testosterone levels during treatment were 1.8-fold and 2.3-fold higher in obese men. Similar results were observed when subjects were categorized by body fat.

CONCLUSIONS

Despite lower pretreatment serum testosterone levels, obese men have higher total and free testosterone levels during leuprolide treatment than men with normal BMI. These differences may contribute to the association between obesity and increased prostate cancer mortality.

Obesity and prostate cancer: a role for adipokines

OBJECTIVES

Many studies have investigated the association between obesity and prostate cancer risk but have yielded inconsistent results. Recent evidence suggests a particular role for obesity in prostate cancer progression. Many studies have investigated the roles of adipose tissue-derived factors (adipokines) as putative molecular mediators between obesity and prostate cancer. This review provides an overview of current evidence that supports such a role for adipokines.

METHODS

A comprehensive literature review was carried out using PubMed to search for articles relating to prostate cancer and the following adipokines: leptin, interleukin 6, vascular endothelial growth factor (VEGF), and adiponectin.

RESULTS

Prostate cancer cells are exposed to adipokines either via the circulation or through locally produced adipokines following invasion of the retropubic fat pad. Circulating levels of most adipokines are positively correlated with obesity; adiponectin is inversely correlated with obesity. High circulating levels of leptin, interleukin 6, and VEGF are associated with increased prostate cancer risk and increased aggressiveness. Adiponectin levels are lower in patients with prostate cancer and are inversely associated with grade of disease. Adipokines exert a variety of biologic effects on prostate cancer cells, modulating cellular differentiation, apoptosis, proliferation, and angiogenesis.

CONCLUSIONS

Evidence suggests a role for obesity and adipokines in promoting the progression of established prostate cancer. Adipokines may contribute to the molecular basis for the association between obesity and prostate cancer, but the complex pathophysiology of both these disease states requires further studies.

Prospective study of adiposity and weight change in relation to prostate cancer incidence and mortality

BACKGROUND

Adiposity has been linked inconsistently with prostate cancer, and few studies have evaluated whether such associations vary by disease aggressiveness.

METHODS

The authors prospectively examined body mass index (BMI) and adult weight change in relation to prostate cancer incidence and mortality in 287,760 men ages 50 years to 71 years at enrollment (1995-1996) in the National Institutes of Health-AARP Diet and Health Study. At baseline, participants completed questionnaires regarding height, weight, and cancer screening practices, including digital rectal examinations and prostate-specific antigen tests. Cox regression analysis was used to calculate relative risks (RR) and 95% confidence intervals (95% CIs).

RESULTS

In total, 9986 incident prostate cancers were identified during 5 years of follow-up, and 173 prostate cancer deaths were ascertained during 6 years of follow-up. In multivariate models, higher baseline BMI was associated with significantly reduced total prostate cancer incidence, largely because of the relationship with localized tumors (for men in the highest BMI category [>or=40 kg/m(2)] vs men in the lowest BMI category [<25 kg/m(2)]: RR, 0.67; 95% CI, 0.50-0.89; P = .0006). Conversely, a significant elevation in prostate cancer mortality was observed at higher BMI levels (BMI <25 kg/m(2): RR, 1.0 [referent group]; BMI 25-29.9 kg/m(2): RR, 1.25; 95% CI, 0.87-1.80; BMI 30-34.9 kg/m(2): RR, 1.46; 95% CI, 0.92-2.33; and BMI >or=35 kg/m(2): RR, 2.12; 95% CI, 1.08-4.15; P = .02). Adult weight gain from age 18 years to baseline also was associated positively with fatal prostate cancer (P = .009), but not with incident disease.

CONCLUSIONS

Although adiposity was not related positively to prostate cancer incidence, higher BMI and adult weight gain increased the risk of dying from prostate cancer.

Obesity is negatively associated with prostate-specific antigen in U.S. men, 2001-2004

BACKGROUND

Recent studies have shown a negative association between body mass index (BMI) and prostate-specific antigen (PSA), a commonly used serum marker for the detection and diagnosis of prostate cancer. We have examined the association between several anthropometric measures and PSA in a nationally representative sample of men.

METHODS

We analyzed data from the 2001-2004 National Health and Nutrition Examination Survey. Participants in this study were men ages >or=40 years without previously diagnosed prostate cancer who had PSA measured. Height, weight, waist circumference, BMI, triceps skinfold, subscapular skinfold, and calculated total body water were examined categorically by quintiles using multiple linear regression models. All tests of significance were two sided.

RESULTS

Among white men, we report a trend for decreasing PSA with increasing weight, BMI, waist circumference, triceps skinfold thickness, and calculated total body water. Among Mexican American men, we found a trend for decreasing PSA with increasing BMI, and among black men we found a trend for decreasing PSA with increasing triceps thickness. None of the interaction terms between race/ethnicity and any of the anthropometric measures were statistically significant. Controlling for age and race/ethnicity in the multiple linear regression model, we found moderate declines in PSA with a 1 SD increase in BMI [5.9% decrease (95% confidence interval, -9.0% to -2.8%) in geometric mean PSA per 5.2-unit increase], weight [5.9% decline (-8.8% to -2.8%) per 17.7-kg increase], waist circumference [6.6% decline (-9.4% to -3.6%) per 13.4-cm increase], triceps skinfold [5.4% decline (-8.9% to -1.8%) per 6.4-mm increase], and calculated total body water [5.7% decline (-8.9% to -2.4%) per 6.5-liter increase].

CONCLUSION

Our population-based, nationally representative results expand the validity of previous studies on obesity and PSA. Higher weight, BMI, waist circumference, triceps skinfold, and total body water are associated with moderately lower PSA values. A prospective study is needed to verify whether this association affects the accuracy of the PSA test in obese men.

Body mass index, weight change, and risk of prostate cancer in the Cancer Prevention Study II Nutrition Cohort

BACKGROUND

Obesity has been associated with aggressive prostate cancer. The extent of this association, which varies by stage and grade, remains unclear. The role of recent weight change had not been previously examined.

METHODS

We examined body mass index (BMI) and weight change in relation to incident prostate cancer by disease stage and grade at diagnosis among 69,991 men in the Cancer Prevention Study II Nutrition Cohort. Participants provided information on height and weight in 1982, and again at enrollment in 1992. During follow-up through June 30, 2003 (excluding the first 2 years of follow-up), we documented 5,252 incident prostate cancers. Cox proportional hazards models were used to estimate rate ratios (RR) and 95% confidence intervals (95% CI).

RESULTS

The association between BMI in 1992 and risk of prostate cancer differed by stage and grade at diagnosis. BMI was inversely associated with risk of nonmetastatic low-grade prostate cancer (RR, 0.84; 95% CI, 0.66-1.06), but BMI was positively associated with risk of nonmetastatic high-grade prostate cancer (RR, 1.22; 95% CI, 0.96-1.55) and risk of metastatic or fatal prostate cancer (RR, 1.54; 95% CI, 1.06-2.23). Compared with weight maintenance, men who lost >11 pounds between 1982 and 1992 were at a decreased risk of nonmetastatic high-grade prostate cancer (RR, 0.58; 95% CI, 0.42-0.79).

CONCLUSION

Obesity increases the risk of more aggressive prostate cancer and may decrease either the occurrence or the likelihood of diagnosis of less-aggressive tumors. Men who lose weight may reduce their risk of prostate cancer.

The regulation of adiponectin receptors in human prostate cancer cell lines

Obesity is a risk factor for prostate cancer, and plasma levels of the adipokine, adiponectin, are low in the former but high in the latter. Adiponectin has been shown to modulate cell proliferation and apoptosis, suggesting that adiponectin and its receptors (Adipo-R1, Adipo-R2) may provide a molecular association between obesity and prostate carcinogenesis. We show for the first time, the protein distribution of Adipo-R1 and Adipo-R2 in LNCaP and PC3 cells, and in human prostate tissue. Using real-time RT-PCR we provide novel data demonstrating the differential regulation of Adipo-R1 and Adipo-R2 mRNA expression by testosterone, 5-alpha dihydrotestosterone, beta-estradiol, tumour necrosis factor-alpha, leptin, and adiponectin in LNCaP and PC3 cells. Our findings suggest that adiponectin and its receptors may contribute to the molecular association between obesity and prostate cancer through a complex interaction with other hormones and cytokines that also play important roles in the pathophysiology of obesity and prostate cancer.

Patterns of cancer incidence, mortality, and prevalence across five continents: defining priorities to reduce cancer disparities in different geographic regions of the world

Efforts to reduce global cancer disparities begin with an understanding of geographic patterns in cancer incidence, mortality, and prevalence. Using the GLOBOCAN (2002) and Cancer Incidence in Five Continents databases, we describe overall cancer incidence, mortality, and prevalence, age-adjusted temporal trends, and age-specific incidence patterns in selected geographic regions of the world. For the eight most common malignancies-cancers of lung, breast, colon and rectum, stomach, prostate, liver, cervix, and esophagus-the most important risk factors, cancer prevention and control measures are briefly reviewed. In 2002, an estimated 11 million new cancer cases and 7 million cancer deaths were reported worldwide; nearly 25 million persons were living with cancer. Among the eight most common cancers, global disparities in cancer incidence, mortality, and prevalence are evident, likely due to complex interactions of nonmodifiable (ie, genetic susceptibility and aging) and modifiable risk factors (ie, tobacco, infectious agents, diet, and physical activity). Indeed, when risk factors among populations are intertwined with differences in individual behaviors, cultural beliefs and practices, socioeconomic conditions, and health care systems, global cancer disparities are inevitable. For the eight most common cancers, priorities for reducing cancer disparities are discussed.