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Many anticipate that application of findings in molecular genetics will help to achieve greater precision in defining high-risk populations that may benefit from chemopreventive interventions. We must recognize, however, that genetic susceptibility, environmental factors, and complex gene-environment interactions are all likely to be risk determinants for most cancers. Cohort studies of twins and cancer indicate that having "identical" genes is generally not a very accurate predictor of cancer incidence. Data from twin studies support the suggestion that environmental factors such as tobacco use significantly influence cancer risk. The complexities of the genetic contribution to disease risk are exemplified by the development of Duchenne muscular dystrophy in only one of monozygotic twin girls, hypothesized to be the result of X chromosome inactivation, with the distribution patterns of the X chromosome being skewed to the female X in the manifesting twin and to the male X in the normal twin. Evidence from transgenic and genetic-environmental studies in animals support the possibility of genetic-environmental interactions. Calorie restriction modifies tumor expression in p53 knockout mice; a high-fat, low-calcium, low-vitamin D diet increases prepolyp hyperplasia formation in Apc-mutated mice; and calorie restriction early in life influences development of obesity in the genetically obese Zucker rat (fafa). Such environmental modulation of gene expression suggests that chemoprevention has the potential to reduce risk for both environmentally and genetically determined cancers. In view of the growing research efforts in chemoprevention, the NCI has developed a Prevention Trials Decision Network (PTDN) to formalize the evaluation and approval process for large-scale chemoprevention trials. The PTDN addresses large trial prioritization and the associated issues of minority recruitment and retention; identification and validation of biomarkers as intermediate endpoints for cancer; and chemopreventive agent selection and development. A comprehensive database is being established to support the PTDN's decision-making process and will help to determine which agents investigated in preclinical and early phase clinical trials should move to large-scale testing. Cohorts for large-scale chemoprevention trials include individuals who are determined to be at high risk as a result of genetic predisposition, carcinogenic exposure, or the presence of biomarkers indicative of increased risk. Current large-scale trials in well-defined, high-risk populations include the Breast Cancer Prevention Trial (tamoxifen), the Prostate Cancer Prevention Trial (finasteride), and the N-(4-hydroxyphenyl) retinamide (4-HPR) breast cancer prevention study being conducted in Milan. Biomarker studies will provide valuable information for refining the design and facilitating the implementation of future large-scale trials. For example, potential biomarkers are being assessed at biopsy in women with ductal carcinoma in situ (DCIS). The women are then randomized to either placebo, tamoxifen, 4-HPR, or tamoxifen plus 4-HPR for 2-4 weeks, at which time surgery is performed and the biomarkers reassessed to determine biomarker modulation by the interventions. For prostate cancer, modulation of prostatic intraepithelial neoplasia (PIN) by 4-HPR and difluoromethylornithine is being investigated; similar studies are being planned for oltipraz, dehydroepiandrosterone, and vitamin E plus selenomethionine. The validation of biomarkers as surrogate endpoints for cancer incidence in high-risk cohorts will allow more agents to be evaluated in shorter studies that use fewer subjects to achieve the desired statistical power.
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PMID:Cancer risk factors for selecting cohorts for large-scale chemoprevention trials. 902 95

The partial androgen deficit of the ageing male is an essential part of the age-related changes of the endocrine system. Clinically relevant disturbances (co-) caused by a relative testosterone-deficit are: changes of body composition (increase of fat mass, decrease of lean tissue mass), decrease of muscle strength and mass, changes of the lipid profile, cardiovascular disease, osteoporosis and anemia. Controlled studies revealed a positive effect of testosterone substitution on body composition, muscle strength, bone metabolism and erythropoesis. Moreover, a protective effect on the development of coronary artery disease could be demonstrated by an improvement of the lipid profile, decrease of obesity and insulin resistance and by a direct effect on the coronary vessels. Clinically evident hypogonadism is a clear indication for testosterone-substitution also in the ageing male, whereas in the case of the partial testosterone-deficit in the absence of sufficient data at this time no general recommendation for substitution can be given; one has to decide about a (experimental) therapy in the individual patient. In every case the contraindications of a testosterone-supplementation (carcinoma of the prostate, elevated PSA-values, polyglobulia, sleep-apnea-syndrome) have to be observed, a continuous survey of the therapy, especially of the prostate is essential. A general recommendation for a substitution with dehydroepiandrosterone (DHEA) can not be given.
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PMID:[Androgen therapy from the viewpoint of the internal medicine physician]. 1181 54

The purpose of the present study was to perform a BPH risk factor analysis in men, relating the prostate gland volume to components of the metabolic syndrome and to identify clues to the etiology of BPH. Our material comprised a consecutive series of 158 patients with lower urinary tract symptoms with or without manifestations of the metabolic syndrome. In this group, the measured volume of the prostate was related consecutively to potential risk factors. The diagnoses atherosclerosis, non-insulin-dependent diabetes mellitus (NIDDM) and treated hypertension were obtained from the patient's medical history. Data on blood pressure, waist and hip measure, body height and weight were collected and body mass index (BMI) and waist/hip ratio (WHR) were calculated. Blood samples were drawn from fasting patients to determine insulin, cholesterol, triglycerides, HDL and LDL-cholesterol, uric acid and ALAT. The prostate gland volume was determined using ultrasound. Our results show that there was a larger prostate gland in men with NIDDM (P=0.0058), treated hypertension (P=0.0317), obesity (P<0.0001), low HDL-cholesterol levels (P=0.0132) and high insulin levels (P<0.0001) than in men without these conditions. The prostate gland volume correlated positively with the systolic blood pressure (r(s)=0.17; P=0.03), obesity (r(s)=0.34; P<0.0001) and fasting insulin (r(s)=0.38; P<0.0001) and negatively with HDL-cholesterol (r(s)=-0.22; P=0.009). On the basis of our findings, we concluded that NIDDM, treated hypertension, obesity, low HDL-cholesterol levels and high insulin levels constitute risk factors for the development of BPH. The results suggest that BPH is a facet of the metabolic syndrome and that BPH patients may share the same metabolic abnormality of a defective insulin-mediated glucose uptake and secondary hyperinsulinemia as patients with the metabolic syndrome. The findings generate a hypothesis of a causal relationship between high insulin levels and the development of BPH. In a clinical setting, the findings of the present report suggest that, in any patient presenting with BPH, the possible presence of NIDDM, hypertension, obesity, high insulin and low HDL-cholesterol levels should be considered. Conversely, in patients suffering from these conditions, the possibility of a clinically important BPH should be kept in mind.
Prostate Cancer Prostatic Dis 1998 Mar
PMID:Components of the metabolic syndrome-risk factors for the development of benign prostatic hyperplasia. 1249 10

Androgens, diet, race and obesity are thought to play some roles in the pathogenesis of prostate cancer. We wanted to evaluate if there were any inter-relationships between prostate specific antigen (PSA), serum testosterone, serum cholesterol, HDL, triglycerides, body mass index (BMI) and race, in older patients with and without prostate cancer (CaP). We evaluated 308 patients referred to urologists in private practice offices and clinics with and without prostate cancer with regard to race, serum PSA, age, serum testosterone, full lipid profile, height and weight, and stage of cancer. We used multivariate analysis, Fisher's exact test and t-tests as well as logistic regression analysis. Data was analyzed using SPSS computer software, and P-values<0.05 were considered statistically significant. Significantly higher levels of serum testosterone were found in black men with CaP than black men without CaP (526+/-28 vs 404+/-19, respectively.) We also found significantly higher levels of serum testosterone in white men with CaP than white men without CaP (409+/-20 vs 302+/-14, respectively, P<0.05). HDL was higher in black men than white men, and triglycerides were higher in white men than black men. Cholesterol was similar across all groups, but BMI was highest in white men with CaP. We also found a significant association between BMI and pathological stage of prostate cancer patients among both black and white men (P<0.05). Our study demonstrated that black men who developed CaP had higher serum testosterone levels, on average, than white men who developed CaP. Furthermore, BMI was highest in white men developing CaP compared to black men, but we found a significant association between pathological stage and BMI in both black and white patients. Although it is controversial whether obesity is considered to be a risk factor for prostate cancer, this small pilot study suggests that BMI may play a role in the progression of the disease once it is established.Prostate Cancer and Prostatic Diseases (2001) 4, 101-105
Prostate Cancer Prostatic Dis 2001
PMID:A pilot study analyzing PSA, serum testosterone, lipid profile, body mass index and race in a small sample of patients with and without carcinoma of the prostate. 1249 46

We present a review of the epidemiological evidence for relations of prostate cancer risk to circulating total and bioavailable androgens, to alterations in the metabolism of insulin-like growth factor-1 (IGF-1), and to anthropometric indices of longitudinal growth (body stature) and overweight. In addition, we review the physiological inter-relationships between insulin, growth hormone/IGF-1 axis, and sex steroid metabolism, as well as the associations of bioavailable sex steroid levels with overweight and obesity. A first conclusion of this review is that, taken together, epidemiological studies have provided little support for the hypothesis that prostate cancer risk is increased in men with elevated total or biovailable testosterone (T). Although one prospective study showed an increased risk in men with low plasma sex hormone-binding globulin (SHBG) and with elevated plasma T for given levels of SHBG, this was not confirmed by results from other cohort studies. A second conclusion is that overweight, which is generally associated with moderate reductions in both total and bioavailable plasma T, appears to be unrelated to any significant increase or decrease in prostate cancer risk. However, significant increases in risk have been observed for men with a taller body stature, or with elevated plasma IGF-1. IGF-1 may directly enhance prostate tumorigenesis by inhibiting apoptosis and by stimulating cell proliferation. In addition, IGF-1 downregulates the synthesis of SHBG, and enhances sex steroid synthesis. Therefore, we do not entirely rule out that due to an elevation of plasma IGF-1 levels, men at increased risk of prostate cancer also have mildly elevated plasma bioavailable T, which epidemiological studies may have failed to demonstrate because of methodological problems. Prostate Cancer and Prostatic Diseases (2000) 3, 157-172
Prostate Cancer Prostatic Dis 2000 Nov
PMID:Plasma androgens, IGF-1, body size, and prostate cancer risk: a synthetic review. 1249 92

Some studies suggest that several tumors have a greater incidence in those patients with a high fat diet, such as colon, breast, and prostate. However, we wanted to determine the effects of obesity alone, independent of diet, on the progression of prostate tumor growth. Using a genetic model of obese and lean Zucker rats, we wanted to demonstrate any sera differences in the concentration of basic fibroblast growth factor (FGF-2) and vascular endothelial cell growth factor (VEGF), two important factors involved in the growth and progression of prostate cancer. We also wanted to investigate if there were any differences in immune function between the two sera, which could also account for uninhibited tumor growth, as well as differences in mitogenic stimulation. Female Zucker rat obese and lean sera were analyzed using ELISA assays for FGF-2, VEGF, and macrophage inflammatory protein-1 alpha (MIP-1a), as a measure of macrophage function. In addition, the sera of lean and obese sera were plated on wells growing LNCaP prostate cancer cells to determine differences in mitogenicity. We found a greater concentration of FGF-2 in the sera from obese Zucker rats compared to lean Zucker rats: 6.32+/-0.56 vs 3.48+/-0.34 pg/ml, respectively, P<0.05). We also demonstrated a greater concentration of VEGF in obese rat sera compared to lean sera: 54.4+/-4.1 vs 38.0+/-2.9 pg/mL, respectively, P<0.05). We detected a trend in mitogenic stimulation among LNCaP cells along the higher concentrations of the dose-response curve (0.72+/-0.06 vs 0.51+/-0.5). However, this was not statistically significant. In addition, we did not find a significant difference in MIP-1a macrophage activity levels between sera. To conclude, we speculate that the greater concentrations of VEGF and FGF-2 in the sera of obese rodents vs lean rodents may account for some of the differences seen in obesity-related tumor growth seen in the human condition. However, the lack of any sera differences of immune function, as measured by macrophage activity, as well as no significant differences on mitogenic proliferation on LNCaP prostate cancer cells, suggests that other mechanisms may exist to explain differences seen in obesity-related prostate tumor biology.
Prostate Cancer Prostatic Dis 2003
PMID:Immune function, mitogenicity, and angiogenic growth factor concentrations in lean and obese rodent sera: implications in obesity-related prostate tumor biology. 1466 68

Obesity-associated prostate cancer (PCa) remains controversial, although most studies rely on body mass index evaluation, which is an indirect measure of fatness. Studies using body fat measurement and disease stratification according to PCa stage found stronger associations between obesity and PCa. Leptin is a pleiotrophic hormone mainly synthesized by adipocytes that acts in peripheral organs such as the prostate. This article reviews obesity-associated leptin's pathophysiological role in PCa progression. PCa development results from some known risk factors. Currently, there is enough evidence suggesting that leptin is an additional factor involved in advanced PCa occurrence, and obesity association with high-grade disease. Life-long exposure to genetic and/or environmental susceptibility factors that predispose to obesity and higher leptin levels may increase the risk for advanced PCa.
Prostate Cancer Prostatic Dis 2006
PMID:The link between obesity and prostate cancer: the leptin pathway and therapeutic perspectives. 1679 46

Studies on the relationship between obesity and prostate cancer incidence are inconsistent. In part, this inconsistency may be due to a differential effect of obesity on low-grade and high-grade cancer or confounding of the association of obesity with prostate cancer risk by diabetes. We investigated the associations of obesity and diabetes with low-grade and high-grade prostate cancer risk. Data were from 10,258 participants (1,936 prostate cancers) in the Prostate Cancer Prevention Trial who all had cancer presence or absence determined by prostate biopsy. Multiple logistic regression was used to model the risk of total prostate cancer, and polytomous logistic regression was used to model the risk of low-grade and high-grade prostate cancer. Compared with men with body mass index < 25, obese men (body mass index > or =30) had an 18% [odds ratio (OR), 0.82; 95% confidence interval (95% CI), 0.69-0.98] decreased risk of low-grade prostate cancer (Gleason <7) and a 29% (OR, 1.29; 95% CI, 1.01-1.67) increased risk of high-grade prostate cancer (Gleason > or =7) or, alternatively, a 78% (OR, 1.78; 95% CI, 1.10-2.87) increased risk defining high-grade cancer as Gleason sum 8 to 10. Diabetes was associated with a 47% (OR, 0.53; 95% CI, 0.34-0.83) reduced risk of low-grade prostate cancer and a 28% (OR, 0.72; 95% CI, 0.55-0.94) reduced risk of high-grade prostate cancer. Associations of obesity or diabetes with cancer risk were not substantially changed by mutually statistical controlling for each other. Obesity increases the risk of high-grade but decreases the risk of low-grade prostate cancer, and this relationship is independent of the lower risk for prostate cancer among men with diabetes.
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PMID:Obesity, diabetes, and risk of prostate cancer: results from the prostate cancer prevention trial. 1722 Mar 51

Increasing prostate volume contributes to urinary tract symptoms and may obscure prostate cancer detection. We investigated the association between obesity and prostate volume, prostate-specific antigen (PSA) and PSA density among 753 men referred for prostate biopsy. Among men with a negative biopsy, prostate volume significantly increased approximately 25% from the lowest to highest body mass index (BMI), waist or hip circumference or height categories. PSA was 0.7 ng/ml lower with a high waist-to-hip ratio. These associations were less consistent among subjects diagnosed with high-grade prostatic intraepithelial neoplasia or cancer. Our data suggest that obesity and height are independently associated with prostate volume..
Prostate Cancer Prostatic Dis 2007
PMID:The association between body size, prostate volume and prostate-specific antigen. 1717 79

Clifton Leaf, in his article "Why We're Losing the War on Cancer," presents criticisms of past research approaches and the small impact of this research thus far on producing cures or substantially extending the life of many cancer patients. It is true that gains in long-term survival for people with advanced cancers have been modest, hindered in part by the heterogeneity of tumors, which allows the cancers to persist using alternate molecular pathways and so evade many cancer therapeutics. In contrast, clinical trials have demonstrated that it is possible to reduce the incidence or improve cancer survival through prevention and early detection. Strides have been made in preventing or detecting early the four deadliest cancers in the United States (i.e., lung, breast, prostate, and colorectal). For example, 7-year follow-up data from the Breast Cancer Prevention Trial (BCPT) provides evidence that tamoxifen reduces the occurrence of invasive breast tumors by more than 40%; recent studies using aromatase inhibitors and raloxifene are also promising. The Prostate Cancer Prevention Trial (PCPT) showed that finasteride reduced prostate cancer incidence by 25%, and the ongoing Selenium and Vitamin E Cancer Prevention Trial (SELECT) is investigating selenium and vitamin E for prostate cancer prevention based on encouraging results from earlier studies. Living a healthy lifestyle, including regular physical activity, avoiding obesity, and eating primarily a plant-based diet has been associated with a lower risk of colorectal cancer. In addition, noninvasive stool DNA tests for early detection are being studied, which may lessen the reluctance of people to be screened for colorectal polyps and cancer. Behavioral and medical approaches for smoking prevention are ways to reduce the incidence of lung cancer, with antinicotine vaccines on the horizon that may help former smokers to avoid relapse. The US National Lung Screening Trial is testing whether early detection via spiral CT screening will reduce lung cancer mortality. Prevention and earlier detection offer efficient and practical strategies to reduce the cancer burden. Several of the suggestions Mr. Leaf makes, such as developing interdisciplinary collaborations and allocating resources to research earlier in the process of carcinogenesis, have become an integral strategy in the National Cancer Institute's (NCI) approach in the past decade, specifically in the realm of cancer prevention and early detection. For example, an aggressive program to identify biomarkers for earlier detection of cancer--the NCI's Early Detection Research Detection (EDRN)--has identified three promising biomarkers since its establishment in 2000. It collaborates with the National Institute of Standards and Technology and extramural scientists to develop validation standards and to identify the best technologies to use for systematic investigations. If these biomarkers can be validated, they might help to reduce cancer mortality.
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PMID:A favorable view: progress in cancer prevention and screening. 1730 81


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