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High circulating vitamin D levels and supplementation may lower prostate cancer mortality. To probe for direct effects of vitamin D signaling in the primary tumor, we assessed how activation of intratumoral vitamin D signaling in prostate cancer is associated with lethal prostate cancer during long-term follow-up. Among 404 participants with primary prostate cancer in the Health Professionals Follow-up Study and the Physicians' Health Study, we defined a gene score of expected activated intratumoral vitamin D signaling consisting of transcriptionally upregulated (CYP27A1 , CYP2R1 , RXRA , RXRB , and VDR) and downregulated genes (CYP24A1 and DHCR7). We contrasted vitamin D signaling in tumors that progressed to lethal disease (metastases/prostate cancer-specific death, n  = 119) over up to three decades of follow-up with indolent tumors that remained nonmetastatic for >8 years post-diagnosis (n  = 285). The gene score was downregulated in tumor tissue compared with tumor-adjacent histologically normal tissue of the same men. Higher vitamin D gene scores were inversely associated with lethal prostate cancer (odds ratio for highest versus lowest quartile: 0.46, 95% confidence interval: 0.21–0.99) in a dose–response fashion and after adjusting for clinical and pathologic factors. This association appeared strongest among men with high predicted plasma 25-hydroxyvitamin D3 and men with body mass index ≥25 kg/m2. Findings were replicated with broader gene sets. These data support the hypothesis that active intratumoral vitamin D signaling is associated with better prostate cancer outcomes and provide further rationale for testing how vitamin D-related interventions after diagnosis could improve prostate cancer survival through effects on the tumor. [ABSTRACT FROM AUTHOR]

Background: Studies have shown improved survival among individuals with cancer with higher levels of social support. Few studies have investigated social support and overall survival (OS) in individuals with advanced prostate cancer in an international cohort. We investigated the associations of marital status and living arrangements with OS among individuals with advanced prostate cancer in the International Registry for Men with Advanced Prostate Cancer (IRONMAN). Methods: IRONMAN is enrolling participants diagnosed with advanced prostate cancer (metastatic hormone-sensitive prostate cancer, mHSPC; castration-resistant prostate cancer, CRPC) from 16 countries. Participants in this analysis were recruited between July 2017 and January 2023. Adjusting for demographics and tumor characteristics, the associations were estimated using Cox regression and stratified by disease state (mHSPC, CRPC), age (<70, =70 years), and continent of enrollment (North America, Europe, Other). Results: We included 2,119 participants with advanced prostate cancer, of whom 427 died during up to 5 years of follow-up (median 6 months). Two-thirds had mHSPC. Most were married/in a civil partnership (79%) and 6% were widowed. Very few married participants were living alone (1%), while most unmarried participants were living alone (70%). Married participants had better OS than unmarried participants [adjusted HR: 1.44; 95% confidence interval (CI): 1.02-2.02]. Widowed participants had the worst survival compared with married individuals (adjusted HR: 1.89; 95% CI: 1.22-2.94). Conclusions: Among those with advanced prostate cancer, unmarried and widowed participants had worse OS compared with married participants. [ABSTRACT FROM AUTHOR]

Background: Low levels of 6-sulfatoxymelatonin, the primary urinary metabolite of melatonin, have been linked to cancer and cardiometabolic outcomes in White and female populations. Methods: We examined the association between adulthood adiposity and 6-sulfatoxymelatonin levels in a racially and ethnically diverse population. Our study included 4,078 men in the Multiethnic Cohort with adiposity measurements at enrollment (1993-1996) and biomarkers measured in urines collected in 1995 and 2005. Multivariable linear regression models were used to estimate the percent change in 6-sulfatoxymelatonin levels and 95% confidence intervals (CI). Associations were examined separately by racial/ethnic group. Results: The prevalence of obesity varied by race and ethnicity, from 10% for Japanese American men to 34% for Native Hawaiian men. Compared with men with normal body mass index (BMI), men who were overweight (-7.8%; 95% CI, -11.9 to -3.5%) and obese (-18.1%; 95% CI, -23.2 to -12.6%) had significantly lower 6-sulfatoxymelatonin levels adjusting for potential confounding factors. Increasing weight gain in adulthood was also associated with lower 6-sulfatoxymelatonin (Ptrend < 0.0001). The inverse associations for BMI and weight change were qualitatively similar across racial and ethnic groups. Conclusions: Obesity is inversely associated with melatonin in a racially diverse population. This finding is relevant given higher rates of obesity among Black, Native Hawaiian, and Latino men, as well as potential racial and ethnic differences in circadian function. [ABSTRACT FROM AUTHOR]

Solute carrier organic anion (SLCO) transporters (OATP transporters) are involved in cellular uptake of drugs and hormones. Germline variants in SLCO1B3 and SLCO2B1 have been implicated in prostate cancer progression and therapy response, including to androgen deprivation and statin medications, but results have appeared heterogeneous. We conducted a cohort study of five single-nucleotide polymorphisms (SNPs) in SLCO1B3 and SLCO2B1 with prior evidence among 3208 men with prostate cancer who participated in the Health Professionals Follow-up Study or the Physicians' Health Study, following participants prospectively after diagnosis over 32 years (median, 14 years) for development of metastases and cancer-specific death (lethal disease, 382 events). Results were suggestive of, but not conclusive for, associations between some SNPs and lethal disease and differences by androgen deprivation and statin use. All candidate SNPs were associated with SLCO mRNA expression in tumor-adjacent prostate tissue. We also conducted a systematic review and harmonized estimates for a dose-response meta-analysis of all available data, including 9 further studies, for a total of 5598 patients and 1473 clinical events. The A allele of the exonic SNP rs12422149 (14% prevalence), which leads to lower cellular testosterone precursor uptake via SLCO2B1, was associated with lower rates of prostate cancer progression (hazard ratio per A allele, 0.80; 95% confidence interval, 0.69–0.93), with little heterogeneity between studies (I 2, 0.27). Collectively, the totality of evidence suggests a strong association between inherited genetic variation in SLCO2B1 and prostate cancer prognosis, with potential clinical use in risk stratification related to androgen deprivation therapy. [ABSTRACT FROM AUTHOR]

Background: The circadian hormone melatonin has anticancer properties, and prior studies suggest a positive association between low melatonin and prostate cancer risk. The purpose of this study was to examine urinary melatonin levels and prostate cancer in a racially/ethnically diverse cohort. Methods: We conducted a nested case-control study, including 1,263 prostate cancer cases and 2,346 controls, sampled from participants in the Multiethnic Cohort Study with prediagnostic urine samples assayed for 6-sulfatoxymelatonin, the primary melatonin metabolite. Conditional logistic regression was used to examine the association between melatonin levels and the development of prostate cancer outcomes (all incident cases, advanced, lethal, high-grade, and aggressive), overall and by race/ethnicity. Results: Among 1,263 cases, 135 were advanced stage, 101 were lethal cases, and 282 were high-grade disease. Median melatonin levels were similar in controls [17.12 ng/mL; interquartile range (IQR), 19.78] and cases (17.93 ng/mL; IQR, 19.76), and we found no significant association between urinary melatonin levels and prostate cancer risk overall or in any clinical or racial subgroup. Conclusions: In this diverse cohort, there was no significant association between melatonin and any prostate cancer outcome, nor were there any differences by racial/ethnic group. [ABSTRACT FROM AUTHOR]