25-Hydroxyvitamin D3 1-alpha-Hydroxylase 1 Aged 1 Article 1 CYP27A1 gene 1 CYP27A1 protein, human 1 CYP27B1 1 CYP27B1 gene 1 CYP27B1 protein, human 1 CYP2R1 1 CYP2R1 gene 1 CYP2R1 protein, human 1 Case-Control Studies 1 Cholestanetriol 26-Monooxygenase 1 Colorectal Neoplasms 1 Cytochrome P450 Family 2 DNA extraction 1 Female 1 Gene Expression Regulation, Neoplastic 1 Gene Frequency 1 Humans 1 Iranian people 1 Male 1 Middle Aged 1 Polymorphism, Single Nucleotide 1 Vitamin D 1 adult 1 aged 1 biosynthesis 1 calcidiol 1 monooxygenase 1 case control study 1