Metabolic syndrome is associated with aggressive prostate cancer regardless of race.

PURPOSE: Recent meta-analyses suggest the Metabolic Syndrome (MS) increases high-grade prostate cancer (PC), although studies are inconsistent and few black men were included. We investigated MS and PC diagnosis in black and white men undergoing prostate biopsy in an equal access healthcare system. We hypothesized MS would be linked with aggressive PC, regardless of race. METHODS: Among men undergoing prostate biopsy at the Durham Veterans Affairs Hospital, medical record data abstraction of diagnosis or treatment for hypertension (≥ 130/85 mmHg), dyslipidemia (HDL < 40 mg/dL), hypertriglyceridemia (≥ 150 mg/dL), diabetes, hyperglycemia (fasting glucose ≥ 100 ml/dL), and central obesity (waist circumference ≥ 40 inches) were done. Biopsy grade group (GG) was categorized as low (GG1) or high (GG2-5). Multinomial logistic regression was used to examine MS (3-5 components) vs. no MS (0-2 components) and diagnosis of high grade and low grade vs. no PC, adjusting for potential confounders. Interactions between race and MS were also tested. RESULTS: Of 1,051 men (57% black), 532 (51%) had MS. Men with MS were older, more likely to be non-black, and had a larger prostate volume (all p ≤ 0.011). On multivariable analysis, MS was associated with high-grade PC (OR = 1.73, 95% CI 1.21-2.48, p = 0.003), but not overall PC (OR = 1.17, 95% CI 0.88-1.57, p = 0.29) or low grade (OR = 0.87, 95% CI 0.62-1.21, p = 0.39). Results were similar in black and non-black men (all p-interactions > 0.25). CONCLUSION: Our data suggest that metabolic dysregulation advances an aggressive PC diagnosis in both black and non-black men. If confirmed, prevention of MS could reduce the risk of developing aggressive PC, including black men at higher risk of PC mortality.

Implications of Regionalizing Care in the Developing World: Impact of Distance to Referral Center on Compliance to Biopsy Recommendations in a Brazilian Prostate Cancer Screening Cohort.

Given growing specialization in medical care, optimal care may require regionalization, which may create access barriers. We tested this within a large prostate cancer (PC) screening program in Brazil. In 2004-2007, Barretos Cancer Hospital prospectively screened men for PC throughout rural Brazil. Men with abnormal screen were referred for follow-up and possible biopsy. We tested the link between distance from screening site to Barretos Cancer Hospital and risk of noncompliance with showing up for biopsy, PC on biopsy and, among those with PC, PC grade using crude and multivariable logistic regression analysis. Among 10,467 men undergoing initial screen, median distance was 257 km (IQR: 135-718 km). On crude and multivariable analyses, farther distance was significantly linked with biopsy noncompliance (OR/100 km: 0.83, P < 0.001). Among men who lived within 150 km of Barretos Cancer Hospital, distance was unrelated to compliance (OR/100 km: 1.09, P=0.87). There was no association between distance and PC risk or PC grade (all P > 0.25). In Brazil, where distances to referral centers can be large, greater distance was related to reduced biopsy compliance in a PC screening cohort. Among men who lived within 150 km, distance was unrelated to compliance. Care regionalization may reduce access when distances are large.

Genome-wide association analysis of metabolic syndrome quantitative traits in the GENNID multiethnic family study.

BACKGROUND: To identify genetic associations of quantitative metabolic syndrome (MetS) traits and characterize heterogeneity across ethnic groups. METHODS: Data was collected from GENetics of Noninsulin dependent Diabetes Mellitus (GENNID), a multiethnic resource of Type 2 diabetic families and included 1520 subjects in 259 African-American, European-American, Japanese-Americans, and Mexican-American families. We focused on eight MetS traits: weight, waist circumference, systolic and diastolic blood pressure, high-density lipoprotein, triglycerides, fasting glucose, and insulin. Using genotyped and imputed data from Illumina's Multiethnic array, we conducted genome-wide association analyses with linear mixed models for all ethnicities, except for the smaller Japanese-American group, where we used additive genetic models with gene-dropping. RESULTS: Findings included ethnic-specific genetic associations and heterogeneity across ethnicities. Most significant associations were outside our candidate linkage regions and were coincident within a gene or intergenic region, with two exceptions in European-American families: (a) within previously identified linkage region on chromosome 2, two significant GLI2-TFCP2L1 associations with weight, and (b) one chromosome 11 variant near CADM1-LINC00900 with pleiotropic blood pressure effects. CONCLUSIONS: This multiethnic family study found genetic heterogeneity and coincident associations (with one case of pleiotropy), highlighting the importance of including diverse populations in genetic research and illustrating the complex genetic architecture underlying MetS.

Asian Race and Risk of Prostate Cancer: Results from the REDUCE Study.

BACKGROUND: Global prostate cancer incidence rates are lower in Asian men than Caucasian men. Whether this is the result of less screening in Asian men remains to be determined. We examined whether Asian race was associated with prostate cancer diagnosis in the Reduction by Dutasteride of Cancer Events (REDUCE) study. METHODS: REDUCE was a 4-year, multicenter, randomized trial of dutasteride versus placebo for prostate cancer prevention among men who underwent prostate-specific antigen (PSA)-independent biopsies at 2 and 4 years. Eligible men were ages 50 to 75 years, had PSA between 2.5 and 10 ng/mL, and a negative prestudy prostate biopsy. We tested the association between Asian and Caucasian race and prostate cancer diagnosis using logistic regression. RESULTS: Of 8,122 men in REDUCE, 5,755 (71%) were Caucasian and 105 (1.8%) were Asian. Asians had lower body mass index (24.8 vs. 26.9 kg/m2, P < 0.001), had smaller prostate volume (35.0 vs. 43.5 cc, P < 0.001), and were less likely to have abnormal digital rectal exams (P = 0.048), but were similar in baseline age, PSA, family history of prostate cancer, and smoking status compared with Caucasian men (all P ≥ 0.164). Asian men were equally likely to receive any on-study biopsy compared with Caucasian men (P = 0.634). After adjusting for potential confounders, Asian men were less likely to be diagnosed with prostate cancer during the 4-year study (OR = 0.49; 95% confidence interval, 0.28-0.88; P = 0.016), compared with Caucasian men. CONCLUSIONS: In REDUCE, where all men underwent biopsies largely independent of PSA, Asian race was associated with lower prostate cancer diagnosis. IMPACT: These findings suggest that lower prostate cancer risk in Asian men may be due to biological, genetic, and/or lifestyle factors.

Serum cholesterol levels and tumor growth in a PTEN-null transgenic mouse model of prostate cancer.

BACKGROUND: Some, but not all, epidemiologic evidence supports a role for cholesterol, the precursor for steroid hormone synthesis, in prostate cancer. Using a PTEN-null transgenic mouse model of prostate cancer, we tested the effect of modifying serum cholesterol levels on prostate tumor development and growth. We hypothesized that serum cholesterol reduction would lower tumor androgens and slow prostate cancer growth. METHODS: PTENloxP/loxP-Cre+ mice consuming ad libitum high fat, high cholesterol diets (40% fat, 1.25% cholesterol) were randomized after weaning to receive the cholesterol uptake inhibitor, ezetimibe (30 mg/kg/day), or no intervention, and sacrificed at 2, 3, or 4 months of age. Serum cholesterol and testosterone were measured by ELISA and intraprostatic androgens by mass spectrometry. Prostate histology was graded, and proliferation and apoptosis in tumor epithelium and stroma was assessed by Ki67 and TUNEL, respectively. RESULTS: Ezetimibe-treated mice had lower serum cholesterol at 4 months (p = 0.031). Serum cholesterol was positively correlated with prostate weight (p = 0.033) and tumor epithelial proliferation (p = 0.069), and negatively correlated with tumor epithelial apoptosis (p = 0.004). Serum cholesterol was unrelated to body weight (p = 0.195). Tumor stromal cell proliferation was reduced in the ezetimibe group (p = 0.010). Increased serum cholesterol at 4 months was associated with elevated intraprostatic DHEA, testosterone, and androstenedione (p = 0.043, p = 0.074, p = 0.031, respectively). However, cholesterol reduction did not significantly affect adenocarcinoma development at 2, 3, or 4 months of age (0, 78, and 100% in ezetimibe-treated vs. 0, 80, and 100% in mice not receiving ezetimibe). CONCLUSIONS: Though serum cholesterol reduction did not significantly affect the rate of adenocarcinoma development in the PTEN-null transgenic mouse model of prostate cancer, it lowered intraprostatic androgens and slowed tumor growth. These findings support a role for serum cholesterol in promoting prostate cancer growth, potentially via enhanced tumor androgen signaling, and may provide new insight into cholesterol-lowering interventions for prostate cancer treatment.

Evidence for Feedback Regulation Following Cholesterol Lowering Therapy in a Prostate Cancer Xenograft Model.

BACKGROUND: Epidemiologic data suggest cholesterol-lowering drugs may prevent the progression of prostate cancer, but not the incidence of the disease. However, the association of combination therapy in cholesterol reduction on prostate or any cancer is unclear. In this study, we compared the effects of the cholesterol lowering drugs simvastatin and ezetimibe alone or in combination on the growth of LAPC-4 prostate cancer in vivo xenografts. METHODS: Proliferation assays were conducted by MTS solution and assessed by Student's t-test. 90 male nude mice were placed on a high-cholesterol Western-diet for 7 days then injected subcutaneously with 1 × 105 LAPC-4 cells. Two weeks post-injection, mice were randomized to control, 11 mg/kg/day simvastatin, 30 mg/kg ezetimibe, or the combination and sacrificed 42 days post-randomization. We used a generalized linear model with the predictor variables of treatment, time, and treatment by time (i.e., interaction term) with tumor volume as the outcome variable. Total serum and tumor cholesterol were measured. Tumoral RNA was extracted and cDNA synthesized from 1 ug of total RNA for quantitative real-time PCR. RESULTS: Simvastatin directly reduced in vitro prostate cell proliferation in a dose-dependent, cell line-specific manner, but ezetimibe had no effect. In vivo, low continuous dosing of ezetimibe, delivered by food, or simvastatin, delivered via an osmotic pump had no effect on tumor growth compared to control mice. In contrast, dual treatment of simvastatin and ezetimibe accelerated tumor growth. Ezetimibe significantly lowered serum cholesterol by 15%, while simvastatin had no effect. Ezetimibe treatment resulted in higher tumor cholesterol. A sixfold induction of low density lipoprotein receptor mRNA was observed in ezetimibe and the combination with simvastatin versus control tumors. CONCLUSIONS: Systemic cholesterol lowering by ezetimibe did not slow tumor growth, nor did the cholesterol independent effects of simvastatin and the combined treatment increased tumor growth. Despite lower serum cholesterol, tumors from ezetimibe treated mice had higher levels of cholesterol. This study suggests that induction of low density lipoprotein receptor is a possible mechanism of resistance that prostate tumors use to counteract the therapeutic effects of lowering serum cholesterol. Prostate 77:446-457, 2017. © 2016 Wiley Periodicals, Inc.