Physiologic serum 1,25 dihydroxyvitamin D is inversely associated with prostatic Ki67 staining in a diverse sample of radical prostatectomy patients.

The correlation between physiologic serum levels of 25 hydroxyvitamin D with both prostatic 25 hydroxyvitamin D and serum 1,25 dihydroxyvitamin D suggests that serum levels are reasonable biomarkers of vitamin D status. Furthermore, serum 1,25 dihydroxyvitamin D has an inverse association with Ki67 staining in tumor cells at physiologic levels and may protect against tumor progression.