The development of fluoroandrogens and fluoroprogestins as potential imaging agents for receptor-positive prostate and breast tumors

The assay of progesterone receptor (PR) concentration in breast tumors and androgen receptor (AR) concentration in prostate tumors enables hormone responsive neoplasms to be distinguished from those that are non-responsive. In principle, a positron-emitting progestin or androgen with suitably high affinity and selectivity for PR and AR, respectively, and an adequately high specific activity might provide a means for imaging receptor-positive tumors and quantifying their receptor content in vivo. The use of fluorine-18 as a radiolabel, coupled with the use of positron emission transaxial tomography, appears to be a most favorable approach in the development of receptor binding radiopharmaceuticals for in vivo imaging. Therefore, we have begun a systematic investigation of the development of fluorine-substituted androgens and progestins that might be prepared in F-18 labeled form as probes for AR and PR. (author)