Absence of Estrogen Receptor in Human Melanoma as Evaluated by a Monoclonal Antiestrogen Receptor Antibody

Abstract

Controversy regarding the presence of estrogen receptor proteins in human melanomas persists despite extensive investigations on this subject. While apparent high-affinity binding has been observed using dextran-coated charcoal assays, several other characteristics of receptor protein have not been observed. The production of free water on incubation of tritiated estradiol (labeled in the C2 position) with melanoma cytosols suggests the possibility that the apparent binding observed is due to phenomena other than specific receptor-steroid interactions. Melanomas from 15 patients were evaluated for the presence of estrogen receptor using immunocytochemical techniques with a monoclonal antibody directed against the human estrogen receptor protein (H222 Sp gamma). Immunohistochemical evaluation included intensity and distribution of staining. None of the 15 cases demonstrated specific immunohistologic reactivity with the anti-receptor antibody. Control breast and uterine tissue confirmed the specificity and sensitivity of the methods. These results suggest that the apparent estrogen-binding capacity of human melanoma tissues is the result of interactions other than with estrogen receptor, and reaffirm the need to investigate alternate steroid protein interactions, such as catechol estrogen formation, in studying sex steroid influences on human melanoma.