Immunohistochemical staining for androgen receptors: a sensitive marker of sebaceous differentiation.

Androgen receptors (AR) are present in normal skin being localized to the basal and differentiating cells of the sebaceous gland, and as such, sebaceous glands are androgen sensitive tissue. Androgen receptor expression was examined in 43 sebaceous neoplasms including 8 sebaceous carcinomas, 22 sebaceous adenomas, 12 specimens showing sebaceous hyperplasia, and 1 sebaceous epithelioma, as well as in 14 squamous cell carcinomas, 2 clear cell acanthomas, and 35 basal cell carcinomas. Epithelial membrane antigen (EMA) expression was also examined in all of the sebaceous neoplasms. All specimens were fixed in formalin and embedded in paraffin. Diffuse positive nuclear androgen receptor antibody immunohistochemical staining was observed in all samples of sebaceous neoplasms, whereas approximately 60% of basal cell carcinomas showed only focal positivity for nuclear androgen receptor immunoreactivity. Clear cell acanthomas and squamous cell carcinomas were uniformly negative. Whereas all sebaceous neoplasms exhibited immunoreactivity for androgen receptors, the staining pattern was more marked in the nuclei of seboblasts and differentiating sebocytes in the adenomatous, hyperplastic, and epitheliomatous lesions than in the nuclei of the less differentiated sebaceous carcinoma cells. All the sebaceous neoplasms except for sebaceous carcinomas exhibited immunoreactivity for EMA. In the sebaceous carcinomas, EMA staining was absent in the most poorly differentiated specimen, but with increasing differentiation, the carcinomas became immunoreactive to EMA. We have shown that the nuclei of sebaceous neoplasms, including sebaceous gland carcinomas, show immunoreactivity for androgen receptors (AR), that immunohistochemical staining for the presence of AR may be a reliable marker of sebaceous differentiation, and that the AR may be a better marker of sebaceous differentiation than EMA, particularly in poorly differentiated sebaceous carcinomas.