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.

Racial disparities in liver cancer: Evidence for a role of environmental contaminants and the epigenome.

Liver cancer incidence has tripled since the early 1980s, making this disease one of the fastest rising types of cancer and the third leading cause of cancer-related deaths worldwide. In the US, incidence varies by geographic location and race, with the highest incidence in the southwestern and southeastern states and among racial minorities such as Hispanic and Black individuals. Prognosis is also poorer among these populations. The observed ethnic disparities do not fully reflect differences in the prevalence of risk factors, e.g., for cirrhosis that may progress to liver cancer or from genetic predisposition. Likely substantial contributors to risk are environmental factors, including chemical and non-chemical stressors; yet, the paucity of mechanistic insights impedes prevention efforts. Here, we review the current literature and evaluate challenges to reducing liver cancer disparities. We also discuss the hypothesis that epigenetic mediators may provide biomarkers for early detection to support interventions that reduce disparities.

Expression of UDP Glucuronosyltransferases 2B15 and 2B17 is associated with methylation status in prostate cancer cells.

Studies have suggested that abrogated expression of detoxification enzymes, UGT2B15 and UGT2B17, are associated with prostate tumour risk and progression. We investigated the role of EGF on the expression of these enzymes since it interacts with signalling pathways to also affect prostate tumour progression and is additionally associated with decreased DNA methylation. The expression of UGT2B15, UGT2B17, de novo methyltransferases, DNMT3A and DNMT3B was assessed in prostate cancer cells (LNCaP) treated with EGF, an EGFR inhibitor PD16893, and the methyltransferase inhibitor, 5-azacytidine, respectively. The results showed that EGF treatment decreased levels of expression of all four genes and that their expression was reversed by PD16893. Treatment with 5-azacytidine, markedly decreased expression of UGT2B15 and UGT2B17 over 85% as well as significantly decreased expression of DNMT3B, but not the expression of DNMT3A. DNMT3B siRNA treated LNCaP cells had decreased expression of UGT2B15 and UGT2B17, while DNMT3A siRNA treated cells had only moderately decreased UGT2B15 expression. Treatment with DNMT methyltransferase inhibitor, RG108, significantly decreased UGT2B17 expression. Additionally, methylation differences between prostate cancer samples and benign prostate samples from an Illumina 450K Methylation Array study were assessed. The results taken together suggest that hypomethylation of the UGT2B15 and UGT2B17 genes contributes to increased risk of prostate cancer and may provide a putative biomarker or epigenetic target for chemotherapeutics. Mechanistic studies are warranted to determine the role of the methylation marks in prostate cancer.

Evaluation of vitamin D biosynthesis and pathway target genes reveals UGT2A1/2 and EGFR polymorphisms associated with epithelial ovarian cancer in African American Women.

An association between genetic variants in the vitamin D receptor (VDR) gene and epithelial ovarian cancer (EOC) was previously reported in women of African ancestry (AA). We sought to examine associations between genetic variants in VDR and additional genes from vitamin D biosynthesis and pathway targets (EGFR, UGT1A, UGT2A1/2, UGT2B, CYP3A4/5, CYP2R1, CYP27B1, CYP24A1, CYP11A1, and GC). Genotyping was performed using the custom-designed 533,631 SNP Illumina OncoArray with imputation to the 1,000 Genomes Phase 3 v5 reference set in 755 EOC cases, including 537 high-grade serous (HGSOC), and 1,235 controls. All subjects are of African ancestry (AA). Logistic regression was performed to estimate odds ratios (OR) and 95% confidence intervals (CI). We further evaluated statistical significance of selected SNPs using the Bayesian False Discovery Probability (BFDP). A significant association with EOC was identified in the UGT2A1/2 region for the SNP rs10017134 (per allele OR = 1.4, 95% CI = 1.2-1.7, P = 1.2 × 10-6 , BFDP = 0.02); and an association with HGSOC was identified in the EGFR region for the SNP rs114972508 (per allele OR = 2.3, 95% CI = 1.6-3.4, P = 1.6 × 10-5 , BFDP = 0.29) and in the UGT2A1/2 region again for rs1017134 (per allele OR = 1.4, 95% CI = 1.2-1.7, P = 2.3 × 10-5 , BFDP = 0.23). Genetic variants in the EGFR and UGT2A1/2 may increase susceptibility of EOC in AA women. Future studies to validate these findings are warranted. Alterations in EGFR and UGT2A1/2 could perturb enzyme efficacy, proliferation in ovaries, impact and mark susceptibility to EOC.

UDP-glucuronosyltransferases and biochemical recurrence in prostate cancer progression.

BACKGROUND: Uridine 5'-diphosphate-glucuronosyltransferase 2B (UGT2B) genes code for enzymes that catalyze the clearance of testosterone, dihydrotestosterone (DHT), and DHT metabolites in the prostate basal and luminal tissue. The expression of the UGT2B15, UGT2B17, and UGT2B28 enzymes has not been evaluated in prostate tissue samples from hormone therapy-naïve patients. METHODS: We determined the expression of UGT2B15, UGT2B17, and UGT2B28 enzymes in 190 prostate tissue samples from surgical specimens of a multiethnic cohort of patients undergoing radical prostatectomy at the Durham Veterans Affairs Medical Center. The association between each protein's percent positive and H-score, a weighted score of staining intensity, and the risk of biochemical recurrence (BCR) was tested using separate Cox proportional hazards models. In an exploratory analysis, UGT2B17 total positive and H-score were divided at the median and we tested the association between UGT2B17 group and risk of BCR. RESULTS: The median follow-up for all patients was 118 months (IQR: 85-144). Of 190, 83 (44%) patients developed BCR. We found no association between UGT2B15 or UGT2B28 and risk of BCR. However, there was a trend for an association between UGT2B17 and BCR (HR = 1.01, 95% CI 1.00-1.02, p = 0.11), though not statistically significant. Upon further investigation, we found that patients with UGT2B17 higher levels of expression had a significant increased risk of BCR on univariable analysis (HR = 1.57, 95% CI 1.02-2.43, p = 0.041), although this association was attenuated in the multivariable model (HR = 1.50, 95% CI 0.94-2.40, p = 0.088). CONCLUSIONS: Our findings suggest that UGT2B17 overexpression may be associated with a significant increased risk of BCR. These results are consistent with previous reports which showed UGT2B17 significantly expressed in advanced prostate cancer including prostate tumor metastases.

Is Body Mass Index the Best Adiposity Measure for Prostate Cancer Risk? Results From a Veterans Affairs Biopsy Cohort.

OBJECTIVE: To test multiple adiposity measures and prostate cancer (PC) risk in men undergoing prostate biopsy. We hypothesized that body mass index (BMI), body fat, and waist circumference would be highly correlated, and all would be associated with aggressive PC, but not overall risk. SUBJECTS AND METHODS: A case (483)-control (496) study among men undergoing prostate biopsy from 2007 to 2016 was conducted at the Durham Veterans Affairs Medical Center. Anthropometric and self-reported measurements were taken. Percent body fat was measured. Associations between adiposity measures and PC risk and high-grade PC (Gleason ≥7) were examined using logistic regression. RESULTS: BMI, percent body fat, and waist circumference were highly correlated (ρ ≥ .79) (P < .001). On multivariable analysis, BMI (P = .011) was associated with overall PC risk, but percent body fat (P = .16) and waist circumference (P = .19) were not. However, all adiposity measurements were associated with high-grade disease (P < .001). We found a strong relationship between self-reported and measured weight (ρ = .97) and height (ρ = .92). CONCLUSION: BMI, body fat, and waist circumference were all highly correlated and associated with aggressive PC. This study supports the idea that higher adiposity is selectively associated with high-grade PC and reinforces the continued use of self-reported BMI as a measure of obesity in epidemiologic studies of PC.

The association between sexual function and prostate cancer risk in US veterans.

Sexual dysfunction and prostate cancer are common among older men. Few studies explored the association between these two illnesses. We examined whether sexual function is associated with prostate cancer risk among older men. Among 448 men undergoing prostate biopsy at the Durham Veterans Affairs Hospital, sexual function was ascertained from the Expanded Prostate Cancer Index Composite sexual assessment. We tested the link between sexual function and prostate cancer risk adjusting for multiple demographic and clinical characteristics using logistic regression. Multinomial logistic regression was used to test the associations with risk of low-grade (Gleason ≤6) and high-grade (Gleason ≥7 or ≥4 + 3) disease versus no cancer. Of 448 men, 209 (47%) had a positive biopsy; these men were less likely to be white (43% vs 55%, P = 0.013), had higher prostate-specific antigen (PSA) (6.0 vs 5.4 ng ml-1 , P < 0.001), but with lower mean sexual function score (47 vs 54, P = 0.007). There was no difference in age, BMI, pack years smoked, history of heart disease and/or diabetes. After adjusting for baseline differences, sexual function was linked with a decreased risk of overall prostate cancer risk (OR: 0.91 per 10-point change in sexual function, P = 0.004) and high-grade disease whether defined as Gleason ≥7 (OR: 0.86, P = 0.001) or ≥4 + 3 (OR: 0.85, P = 0.009). Sexual function was unrelated to low-grade prostate cancer (OR: 0.94, P = 0.13). Thus, among men undergoing prostate biopsy, higher sexual function was associated with a decreased risk of overall and high-grade prostate cancer. Confirmatory studies are needed.

Xenobiotic Metabolism in Mice Lacking the UDP-Glucuronosyltransferase 2 Family.

UDP-Glucuronosyltransferases (UGTs) conjugate a glucuronyl group from glucuronic acid to a wide range of lipophilic substrates to form a hydrophilic glucuronide conjugate. The glucuronide generally has decreased bioactivity and increased water solubility to facilitate excretion. Glucuronidation represents an important detoxification pathway for both endogenous waste products and xenobiotics, including drugs and harmful industrial chemicals. Two clinically significant families of UGT enzymes are present in mammals: UGT1s and UGT2s. Although the two families are distinct in gene structure, studies using recombinant enzymes have shown considerable overlap in their ability to glucuronidate many substrates, often obscuring the relative importance of the two families in the clearance of particular substrates in vivo. To address this limitation, we have generated a mouse line, termed ΔUgt2, in which the entire Ugt2 gene family, extending over 609 kilobase pairs, is excised. This mouse line provides a means to determine the contributions of the two UGT families in vivo. We demonstrate the utility of these animals by defining for the first time the in vivo contributions of the UGT1 and UGT2 families to glucuronidation of the environmental estrogenic agent bisphenol A (BPA). The highest activity toward this chemical is reported for human and rodent UGT2 enzymes. Surprisingly, our studies using the ΔUgt2 mice demonstrate that, while both UGT1 and UGT2 isoforms can conjugate BPA, clearance is largely dependent on UGT1s.

Carbohydrate intake, glycemic index and prostate cancer risk.

BACKGROUND: Reported associations between dietary carbohydrate and prostate cancer (PC) risk are poorly characterized by race. METHODS: We analyzed the association between carbohydrate intake, glycemic index (GI), and PC risk in a study of white (N = 262) and black (N = 168) veterans at the Durham VA Hospital. Cases were 156 men with biopsy-confirmed PC and controls (N = 274) had a PSA test but were not recommended for biopsy. Diet was assessed before biopsy with a self-administered food frequency questionnaire. Logistic regression models were used to estimate PC risk. RESULTS: In multivariable analyzes, higher carbohydrate intake, measured as percent of energy from carbohydrates, was associated with reduced PC risk (3rd vs. 1st tertile, OR = 0.41, 95% CI 0.21-0.81, P = 0.010), though this only reached significance in white men (p-trend = 0.029). GI was unrelated to PC risk among all men, but suggestively linked with reduced PC risk in white men (p-trend = 0.066) and increased PC risk in black men (p-trend = 0.172), however, the associations were not significant. Fiber intake was not associated with PC risk (all p-trends > 0.55). Higher carbohydrate intake was associated with reduced risk of high-grade (p-trend = 0.016), but not low-grade PC (p-trend = 0.593). CONCLUSION: Higher carbohydrate intake may be associated with reduced risk of overall and high-grade PC. Future larger studies are needed to confirm these findings.

Harnessing mobile genetic elements to explore gene regulation.

Sequences that regulate expression of a gene in cis but are located at large distances along the DNA from the gene, as found with most developmentally regulated genes in higher vertebrates, are difficult to identify if those sequences are not conserved across species. Mutating suspected gene-regulatory sequences to alter expression then becomes a hit-or-miss affair. The relaxed specificity of transposon insertions offers an opportunity to develop alternate strategies, to scan in an unbiased manner, pieces of chromosomal DNA cloned in BACs for transcription enhancing elements. This article illustrates how insertions of Tn10 with enhancer-traps into BAC DNA containing the gene, and its germ-line expression in zebrafish, have identified distal regulatory elements functionally. Transposition of Tn10 first introduces the enhancer-trap with a loxP site randomly into BAC DNA. Cre-recombination between the inserted loxP and the loxP endogenous to a BAC-end positions the enhancer-trap to the newly created truncated end of BAC DNA. The procedure generates a library of integration-ready enhancer-trap BACs with progressive truncations from an end in a single experiment. Individual enhancer-trap BACs from the library can be evaluated functionally in zebrafish or mice. Furthermore, the ability to readily alter sequences in a small transposon plasmid containing a regulatory domain of the gene allows re-introduction of altered parts of a BAC back into itself. It serves as a useful strategy to functionally dissect multiple discontinuous regulatory domains of a gene quickly. These methodologies have been successfully used in identifying novel regulatory domains of the Amyloid Precursor Protein (appb) gene in zebrafish, and provided important clues for regulation of the gene in humans.

The association between race and prostate cancer risk on initial biopsy in an equal access, multiethnic cohort.

PURPOSE: Population-based studies have established a link between race and prostate cancer (PC) risk, but whether race predicts PC after adjusting for clinical characteristics is unclear. We investigated the association between race and risk of low- and high-grade PC in men undergoing initial prostate biopsy in an equal access medical center. METHODS: We conducted a retrospective record review of 887 men (48.6 % black, 51.4 % white) from the Durham Veterans Affairs Medical Center who underwent initial prostate biopsy between 2001 and 2009. Multivariable logistic regression analysis of race and biopsy outcome was conducted adjusting for age, body mass index, number of cores taken, prostate-specific antigen (PSA), and digital rectal examination findings. Multinomial logistic regression was used to test the association between black race and PC grade (Gleason <7 vs. ≥7). RESULTS: Black men were younger at biopsy (61 vs. 65 years, p < 0.001) and had a higher pre-biopsy PSA (6.6 vs. 5.8 ng/ml, p = 0.001). A total of 499 men had PC on biopsy (245 low grade; 254 high grade). In multivariable analyses, black race was significantly predictive of PC overall [odds ratio 1.50, p = 0.006] and high-grade PC [relative risk ratio (RRR) 1.84, p = 0.001], but was not significantly associated with low-grade PC (RRR 1.29, p = 0.139). CONCLUSION: In an equal access healthcare facility, black race was associated with greater risk of PC detection on initial biopsy and of high-grade PC after adjusting for clinical characteristics. Additional investigation of mechanisms linking black race and PC risk and PC aggressiveness is needed.

Novel associations of UDP-glucuronosyltransferase 2B gene variants with prostate cancer risk in a multiethnic study.

BACKGROUND: We have previously shown that a functional polymorphism of the UGT2B15 gene (rs1902023) was associated with increased risk of prostate cancer (PC). Novel functional polymorphisms of the UGT2B17 and UGT2B15 genes have been recently characterized by in vitro assays but have not been evaluated in epidemiologic studies. METHODS: Fifteen functional SNPs of the UGT2B17 and UGT2B15 genes, including cis-acting UGT2B gene SNPs, were genotyped in African American and Caucasian men (233 PC cases and 342 controls). Regression models were used to analyze the association between SNPs and PC risk. RESULTS: After adjusting for race, age and BMI, we found that six UGT2B15 SNPs (rs4148269, rs3100, rs9994887, rs13112099, rs7686914 and rs7696472) were associated with an increased risk of PC in log-additive models (p < 0.05). A SNP cis-acting on UGT2B17 and UGT2B15 expression (rs17147338) was also associated with increased risk of prostate cancer (OR = 1.65, 95% CI = 1.00-2.70); while a stronger association among men with high Gleason sum was observed for SNPs rs4148269 and rs3100. CONCLUSIONS: Although small sample size limits inference, we report novel associations between UGT2B15 and UGT2B17 variants and PC risk. These associations with PC risk in men with high Gleason sum, more frequently found in African American men, support the relevance of genetic differences in the androgen metabolism pathway, which could explain, in part, the high incidence of PC among African American men. Larger studies are required.

Association between exercise and primary incidence of prostate cancer: does race matter?

BACKGROUND: Exercise is a modifiable lifestyle risk factor associated with prostate cancer risk reduction. However, whether this association is different as a function of race is unclear. In the current study, the authors attempted to characterize the link between exercise and prostate cancer (CaP) in white and black American men. METHODS: Using a prospective design, 307 men (164 of whom were white and 143 of whom were black) who were undergoing prostate biopsy completed a self-reported survey that assessed exercise behavior (metabolic equivalent [MET] hours per week). Crude and adjusted logistic regression analyses were used to estimate the risk of prostate cancer controlling for age, body mass index, digital rectal examination findings, previous biopsy, Charlson comorbidity score, and family history of CaP stratified by self-reported race. RESULTS: There was no significant difference noted with regard to the amount of exercise between racial groups (P = .12). Higher amounts of MET hours per week were associated with a decreased risk of CaP for white men in both crude (P = .02) and adjusted (P = .04) regression models. Among whites, men who exercised ≥ 9 MET hours per week were less likely to have a positive biopsy result compared with men exercising < 9 MET hours per week (odds ratio, 0.47; 95% confidence interval, 0.22-0.99 [P = .047]). There was no association noted between MET hours per week and risk of CaP among black men in both crude (P = .79) and adjusted (P = .76) regression models. CONCLUSIONS: In a prospective cohort of men undergoing biopsy, increased exercise, measured as MET hours per week, was found to be associated with CaP risk reduction among white but not black men. Investigating race-specific mechanisms by which exercise modifies CaP risk and why these mechanisms disfavor black men in particular are warranted.

Vitamin D receptor (VDR) polymorphisms and risk of ovarian cancer in Caucasian and African American women.

OBJECTIVE: Polymorphisms in the vitamin D receptor (VDR) gene have been shown in some studies to be associated with the risk of epithelial ovarian cancer (EOC) in Caucasian women. There are no published reports among African Americans. METHODS: Case-control data from the North Carolina Ovarian Cancer Study were analyzed using logistic regression to determine the association between seven VDR polymorphisms and EOC in both Caucasians (513 cases, 532 controls) and African Americans (74 cases, 79 controls). In a larger sample of African-Americans (125 cases, 155 controls), we assessed associations between six SNPs in proximity of rs7975232. RESULTS: African American women who carried at least one minor allele of rs7975232 were at higher risk for invasive EOC controlling for age and admixture with an odds ratio (OR) for association under the log-additive model of 2.08 (95% confidence interval (CI)=1.19, 3.63, p=0.010). No association was observed between any of the VDR variants and EOC among Caucasians. A larger sample of African Americans revealed a nearly two-fold increased risk of invasive EOC associated with rs7305032, a SNP in proximity to rs7975232 (R(2)=0.369) with a log-additive OR of 1.87 (95% CI=1.20, 2.93, p=0.006). CONCLUSIONS: This is the first report showing VDR variants associated with ovarian cancer risk in African American women. A larger study of African American women is needed to confirm these findings. These results imply that vitamin D exposure is a possible modifiable risk factor of ovarian cancer among African Americans.

Association of uridine diphosphate-glucuronosyltransferase 2B gene variants with serum glucuronide levels and prostate cancer risk.

AIMS: Uridine diphosphate-glucuronosyltransferase 2B (UGT2B) enzymes conjugate testosterone metabolites to enable their excretion in humans. The functional significance of the UGT2B genetic variants has never been described in humans. We evaluated UGT2B variants in relation to plasma androstane-3α,17ß-diol-glucuronide (AAG) levels and the prostate cancer risk. RESULTS: AAG levels were measured in sera from 150 controls and compared to the polymorphisms of UGT2B17, UGT2B15, and UGT2B7. Genomic DNA from controls (301) and cases (148) was genotyped for the polymorphisms, and odds ratios (ORs) and 95% confidence intervals (95% CIs) were calculated using unconditional logistic regression analyses. Having two copies of UGT2B17 was associated with higher AAG levels in controls among Whites (p=0.02), but not Blacks (p=0.82). Logistic regression models adjusting for age and race revealed that homozygosity for the G allele of the UGT2B15(D85Y) polymorphism was directly associated with the prostate cancer risk (OR=2.70, 95% CI=1.28, 5.55). CONCLUSIONS: While the small sample size limits inference, our findings suggest that an association between the UGT2B17 copy number variant (CNV) and serum AAG levels in Whites, but unexpectedly not in Blacks. This novel observation suggests that genetic determinants of AAG levels in Blacks are unrelated to the UGT2B17 CNV. This study replicates the results that show an association of UGT215(D85Y) with an increased prostate cancer risk.

Associations between Intake of Folate, Methionine, and Vitamins B-12, B-6 and Prostate Cancer Risk in American Veterans.

Prostate cancer (PC) is the second leading cause of cancer death in men. Recent reports suggest that excess of nutrients involved in the one-carbon metabolism pathway increases PC risk; however, empirical data are lacking. Veteran American men (272 controls and 144 PC cases) who attended the Durham Veteran American Medical Center between 2004-2009 were enrolled into a case-control study. Intake of folate, vitamin B12, B6, and methionine were measured using a food frequency questionnaire. Regression models were used to evaluate the association among one-carbon cycle nutrients, MTHFR genetic variants, and prostate cancer. Higher dietary methionine intake was associated with PC risk (OR = 2.1; 95%CI 1.1-3.9) The risk was most pronounced in men with Gleason sum <7 (OR = 2.75; 95%CI 1.32- 5.73). The association of higher methionine intake and PC risk was only apparent in men who carried at least one MTHFR A1298C allele (OR = 6.7; 95%CI = 1.6-27.8), compared to MTHFR A1298A noncarrier men (OR = 0.9; 95%CI = 0.24-3.92) (p-interaction = 0.045). There was no evidence for associations between B vitamins (folate, B12, and B6) and PC risk. Our results suggest that carrying the MTHFR A1298C variants modifies the association between high methionine intake and PC risk. Larger studies are required to validate these findings.

Dietary calcium and risk for prostate cancer: a case-control study among US veterans.

OBJECTIVE: The objective of this study was to examine the association between calcium intake and prostate cancer risk. We hypothesized that calcium intake would be positively associated with lower risk for prostate cancer. METHODS: We used data from a case-control study conducted among veterans between 2007 and 2010 at the Durham Veterans Affairs Medical Center. The study consisted of 108 biopsy-positive prostate cancer cases, 161 biopsy-negative controls, and 237 healthy controls. We also determined whether these associations differed for blacks and whites or for low-grade (Gleason score <7) and high-grade prostate cancer (Gleason score ≥7). We administered the Harvard food frequency questionnaire to assess diet and estimate calcium intake. We used logistic regression models to obtain odds ratios (ORs) and 95% confidence intervals (CIs). RESULTS: Intake of calcium from food was inversely related to risk for prostate cancer among all races in a comparison of cases and biopsy-negative controls (P = .05) and cases and healthy controls (P = .02). Total calcium was associated with lower prostate cancer risk among black men but not among white men in analyses of healthy controls. The highest tertile of calcium from food was associated with lower risk for high-grade prostate cancer in a comparison of high-grade cases and biopsy-negative controls (OR, 0.37; 95% CI, 0.15-0.90) and high-grade cases and healthy controls (OR, 0.38; 95% CI, 0.17-0.86). CONCLUSION: Calcium from food is associated with lower risk for prostate cancer, particularly among black men, and lower risk for high-grade prostate cancer among all men.

A high ratio of dietary n-6/n-3 polyunsaturated fatty acids is associated with increased risk of prostate cancer.

Experimental studies suggest omega-3 (n-3) polyunsaturated fatty acids (PUFA) suppress and n-6 PUFA promote prostate tumor carcinogenesis. Epidemiologic evidence remains inconclusive. The objectives of this study were to examine the association between n-3 and n-6 PUFA and prostate cancer risk and determine if these associations differ by race or disease aggressiveness. We hypothesize that high intakes of n-3 and n-6 PUFA will be associated with lower and higher prostate cancer risk, respectively. A case-control study comprising 79 prostate cancer cases and 187 controls was conducted at the Durham VA Medical Center. Diet was assessed using a food frequency questionnaire. Logistic regression analyses were used to obtain odds ratios (ORs) and 95% confidence intervals (95% CI) for the associations between n-3 and n-6 PUFA intakes, the dietary ratio of n-6/n-3 fatty acids, and prostate cancer risk. Our results showed no significant associations between specific n-3 or n-6 PUFA intakes and prostate cancer risk. The highest dietary ratio of n-6/n-3 was significantly associated with elevated risk of high-grade (OR, 3.55; 95% CI, 1.18-10.69; P(trend) = 0.03), but not low-grade prostate cancer (OR, 0.95; 95% CI, 0.43-2.17). In race-specific analyses, an increasing dietary ratio of n-6/n-3 fatty acids correlated with higher prostate cancer risk among white men (P(trend) = 0.05), but not black men. In conclusion, our findings suggest that a high dietary ratio of n-6/n-3 fatty acids may increase the risk of overall prostate cancer among white men and possibly increase the risk of high-grade prostate cancer among all men.

Primary peritoneal and ovarian cancers: an epidemiological comparative analysis.

We performed case-control analyses using data from the North Carolina Ovarian Cancer Study to determine risk factors that distinguish primary peritoneal cancer (PPC) from epithelial ovarian cancer (EOC). Our risk factor analyses were restricted to invasive serous cancers including 495 EOC cases, 62 PPC cases and 1,086 control women. Logistic regression analyses were used to calculate adjusted odds ratios and 95% confidence intervals for risk factor associations. Although many case-control associations for the invasive serous PPC cases were similar to those of the invasive serous EOC cases, some differences were observed including a twofold increase in risk of invasive serous PPC in women who were >or=35 years at last pregnancy, whereas a decreased risk was observed for invasive serous EOC risk. We could not confirm a previous report of an association between tubal ligation and PPC, a factor consistently associated with a decreased risk of EOC. The difference in the risk factor associations between invasive serous PPC and EOC cancers suggests divergent molecular development of peritoneal and ovarian cancers. A larger study to determine risk factors for invasive serous PPC is warranted.

Differential activation and regulation of CXCR1 and CXCR2 by CXCL8 monomer and dimer.

CXCL8 (also known as IL-8) activates CXCR1 and CXCR2 to mediate neutrophil recruitment and trigger cytotoxic effect at sites of infection. Under physiological conditions, CXCL8 could exist as monomers, dimers, or a mixture of monomers and dimers. Therefore, both forms of CXCL8 could interact with CXCR1 and CXCR2 with different affinities and potencies to mediate different cellular responses. In the present study, we have used a "trapped" nonassociating monomer (L25NMe) and a nondissociating dimer (R26C) to investigate their activities for human neutrophils that express both receptors and for RBL-2H3 cells stably expressing either CXCR1(RBL-CXCR1) or CXCR2 (RBL-CXCR2). The monomer was more active than the dimer for activities such as intracellular Ca(2+) mobilization, phosphoinositide hydrolysis, chemotaxis. and exocytosis. Receptor regulation, however, is distinct for each receptor. The rate of monomer-mediated regulation of CXCR1 is greater for activities such as phosphorylation, desensitization, beta-arrestin translocation, and internalization. In contrast, for CXCR2, both monomeric and dimeric CXCL8 mediate these activities to a similar extent. Interestingly, receptor-mediated signal-regulated kinase (ERK) phosphorylation in response to all three CXCL8 variants was more sustained for CXCR2 relative to CXCR1. Taken together, the results indicate that the CXCL8 monomer and dimer differentially activate and regulate CXCR1 and CXCR2 receptors. These distinct properties of the ligand and the receptors play a critical role in orchestrating neutrophil recruitment and eliciting cytotoxic activity during an inflammatory response.