Key points are not available for this paper at this time.
THE idea to write this review began a number of years ago when one of us (D.R.C.) was working in Dr. William L. McGuire's laboratory in San Antonio, Texas,1 where we were involved in the study of estrogen receptor(s) (ER) and estrogen-regulated proteins in breast cancer. At that time ER were beginning to be identified in tissues not considered classic targets for estrogens. The idea of reviewing the literature on the presence of ER in nontarget tissues did not prosper because there were methodological problems that could give false positives for ER, such as those reported in melanomas (1). However, at that time ER could be detected by ligand binding assays. More than 10 yr have passed and the study of ER has been improved with the advent and widespread use of monoclonal antibodies against the receptor protein. The presence of ER has been described in numerous normal and pathological tissues using ligandbinding and immunochemical assays. In addition, ER have also been studied at the messenger RNA (mRNA) and DNA level. We can now explore whether the receptor is functional and whether it controls gene and cell functions.
Ciocca et al. (Wed,) studied this question.