Yuan C, et al. - Researchers investigated the relationships of bioavailable 25-hydroxyvitamin D [25(OH)D] and vitamin D binding protein (VDBP) with the risk of advanced and lethal prostate cancer in this prospective case–control study of 156 pairs of advanced prostate cancer cases and controls. Prediagnostic circulating 25(OH)D and VDBP was measured and bioavailable 25(OH)D was calculated using a validated formula. Observations revealed no association of VDBP levels with risk of advanced prostate cancer, however, an interaction between total 25(OH)D levels and VDBP levels in relation to risk of advanced prostate cancer was evident. Data thereby suggest that VDBP levels may influence the association between total 25(OH)D levels and risk of advanced and lethal prostate cancer.