Downregulation of erythroid differentiation regulator 1 as a novel marker of skin tumors

Summary: Background: Erythroid differentiation regulator 1 is decreased in malignant melanoma. However, the expression of erythroid differentiation regulator 1 has not been reported in normal epidermis, vessel, nerve, dermal adnexae, and various skin tumors. Methods: To investigate the expression of erythroid differentiation regulator 1 in normal skin and various skin tumors, immunohistochemical analysis of normal skin, epidermal tumors, sebaceous tumors, and eccrine tumors was performed. The image analysis was quantitatively performed using HistoQuant^™ software. Results: Erythroid differentiation regulator 1 was strongly expressed in the nuclei of normal epidermis, sebaceous gland, eccrine gland, vessel, and nerve. Expression of erythroid differentiation regulator 1 was weak in seborrheic keratosis, sebaceous hyperplasia, and eccrine spiradenoma. Erythroid differentiation regulator 1 was rarely observed in malignant skin tumors, including squamous cell carcinoma, basal cell carcinoma, malignant melanoma, sebaceous carcinoma, and eccrine porocarcinoma. Conclusions: The expression of erythroid differentiation regulator 1 was negatively correlated with the malignant potential in various skin tumors. The results support the role of erythroid differentiation regulator 1 in cutaneous carcinogenesis and indicate its potential as a novel marker of skin tumors.