Oestrogen receptor‐β expression in melanocytic lesions

  Melanomas rarely occur before puberty, have a higher death rate for males, and tend to be more invasive during pregnancy. Prior to the discovery of a second oestrogen receptor (ER β ), studies with the initial oestrogen receptor, ER α , showed no obvious role for oestrogen in the pathophysiology of benign or malignant melanocytic lesions. To investigate the specific immunostaining patterns of ER α and ER β , benign nevocytic nevi, dysplastic nevi with mild, moderate and severe cytological atypia, lentigo malignas and melanomas of varying depth (Clark) and thickness (Breslow) were studied. ER β but not ER α was the predominant oestrogen receptor we found in all types of benign and malignant melanocytic lesions. The most intense ER β immunostaining was seen in melanocytes in dysplastic nevi with severe cytological atypia and in lentigo malignas. ER β expression levels also correlated with the malignant tumor microenvironment; i.e., melanocytes in proximity with keratinocytes>deeper dermal melanocytes in contact with stroma>minimally invasive melanomas>Clark Level III/IV or thick melanomas (Breslow). Discovery that ER β expression varies in relation to the tumor microenvironment and increasing depth of invasion suggests its possible usefulness as a surrogate marker for neoplasia and prognosis in malignant melanoma.