Immunohistochemical staining for androgen receptors - A sensitive marker of sebaceous differentiation

Androgen receptors (AR) are present in normal skin being localized to the b asal and differentiating cells of the sebaceous gland, and as such, sebaceo us glands art: androgen sensitive tissue. Androgen receptor expression was examined in 43 sebaceous neoplasms including 8 sebaceous carcinomas, 22 seb aceous adenomas, 12 specimens showing sebaceous hyperplasia, and 1 sebaceou s epithelioma, as well as in 14 squamous cell carcinomas, 2 clear cell acan thomas, and 35 basal cell carcinomas. Epithelial membrane antigen (EMA) exp ression was also examined in all of the sebaceous neoplasms. All specimens were fixed in formalin and embedded in paraffin. Diffuse positive nuclear a ndrogen receptor antibody immunohistochemical staining was observed in all samples of sebaceous neoplasms, whereas approximately 60% of basal cell car cinomas showed only focal positivity for nuclear androgen receptor immunore activity. Clear cell acanthomas and squamous cell carcinomas were uniformly negative. Whereas all sebaceous neoplasms exhibited immunoreactivity for a ndrogen receptors, the staining pattern was more marked in the nuclei of se boblasts and differentiating sebocytes in the adenomatous, hyperplastic, an d epitheliomatous lesions than in the nuclei of the less differentiated seb aceous carcinoma cells. Al the sebaceous neoplasms except for sebaceous car cinomas exhibited immunoreactivity for EMA, In the sebaceous carcinomas, EM A staining was absent in the most pearly differentiated specimen, but with increasing differentiation, the carcinomas became immunoreactive to EMA. We have shown that the nuclei of sebaceous neoplasms, including sebaceous gla nd carcinomas, show immunoreactivity for androgen receptors (AR), that immu nohistochemical staining for the presence of AR may be a reliable marker of sebaceous differentiation, and that the AR may be a better marker of sebac eous differentiation than EMA, particularly in poorly differentiated sebace ous carcinomas.