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, VDR) and downregulated genes (CYP24A1, 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 to 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 vs. lowest quartile: 0.46, 95% CI: 0.21 to 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.
Carcinogenesis. 2024 Aug 09 [Epub ahead of print]
Jane B Vaselkiv, Irene M Shui, Sydney T Grob, Caroline I Ericsson, Isabel Giovannucci, Cheng Peng, Stephen P Finn, Lorelei A Mucci, Kathryn L Penney, Konrad H Stopsack
Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA, USA., Merck & Co., Inc., Kenilworth, NJ, USA., Department of Pathology, Trinity College Dublin, Dublin, Ireland.