The role of DOG1 immunohistochemistry in dermatopathology

This study was designed to evaluate the immunoexpression of DOG1, a specific marker expressed in gastrointestinal stromal tumors, in normal skin tissues and cutaneous epithelial tumors.

DOG1 immunostaining extent, intensity and pattern were evaluated in 69 cutaneous apocrine/eccrine tumors, 11 sebaceous tumors, 46 follicular tumors, 52 keratinocytic tumors and perilesional normal tissues.

In normal tissues, DOG1 was expressed strongly in the intercellular canaliculi of eccrine glands, moderately in the myoepithelial cells of mammary and anogenital mammary-like glands, and weakly or not at all in the periphery of sebaceous lobules and the lower layer of epidermis and follicular infundibulum. All apocrine-type cutaneous mixed tumors showed apical-luminal positivity for DOG1, and 4/9 of these tumors included intercellular canaliculi highlighted by DOG1 immunostaining. Other sweat gland tumors, including hidrocystadenoma, spiradenoma, cylindroma and apocrine carcinoma, also expressed DOG1 focally with an apical-luminal pattern. Although slight membranous positivity for DOG1 was observed in various tumor types, hidradenoma papilliferum exhibited diffuse membranous DOG1 staining in the myoepithelial cells.

DOG1 is a novel marker for identifying intercellular canaliculi and is a potential immunomarker of myoepithelial cells specific to mammary glands, anogenital mammary-like glands and tumors originating therein.