CYP17 and breast cancer risk: The polymorphism in the 5 ' flanking area ofthe gene does not influence binding to Sp-1

The ability of a motif of the CYP17 5' untranslated region, created by a po lymorphic T to C substitution, to bind to the human transcription factor Sp -1 was investigated. No binding of any of the polymorphic alleles was obser ved in electromobility shift assay. No other sequence within +1 to +100 of each of the CYP17 alleles formed complex with the Sp-l or enhanced binding to the polymorphic CACC box. Genotyping of 510 breast cancer patients and 2 01 controls revealed no difference in genotype frequencies. Age at onset, t umor grade, lymph node status and distant metastases, stage, and estrogen a nd progesterone receptor status were not associated with the CYP17 genotype .