Canine melanocytes: Immunohistochemical expression of melanocytic markers in different somatic areas

• Published in: Veterinary dermatology 2023-08, Vol.34 (4), p.284-297
• Main Authors: Porcellato, Ilaria, Orlandi, Margherita, Lo Giudice, Adriana, Sforna, Monica, Mechelli, Luca, Brachelente, Chiara
• Format: Article
• Language: English
• Subjects: Abdomen; Animals; canine; Dog Diseases - diagnosis; Dogs; Epidermis; Epidermis - pathology; Eyelid; Immunofluorescence; Immunohistochemistry; MART-1 Antigen - metabolism; Melan A; Melanocytes; Melanocytes - pathology; Melanoma; Melanoma - diagnosis; Melanoma - veterinary; Microphthalmia-associated transcription factor; MITF; Mucosa; Necropsy; Neural crest; Sensory integration; Skin; Skin Neoplasms - pathology; Skin Neoplasms - veterinary; SOX‐10; TRP1
• ISSN: 0959-4493; 1365-3164
• DOI: 10.1111/vde.13150

Background Melanoblasts originate in the neural crest from where they migrate to peripheral tissues and differentiate into melanocytes. Alteration during melanocyte development and life can cause different diseases, ranging from pigmentary disorders and decreased visual and auditory functions, to tumours such as melanoma. Location and phenotypical features of melanocytes have been characterised in different species, yet data on dogs are lacking. Objective This study investigates the expression of melanocytic markers Melan A, PNL2, TRP1, TRP2, SOX‐10 and MITF in melanocytes of selected cutaneous and mucosal surfaces of dogs. Animals At necropsy, samples from five dogs were harvested from oral mucosa, mucocutaneous junction, eyelid, nose and haired skin (abdomen, back, pinna, head). Materials and Methods Immunohistochemical and immunofluorescence analyses were performed to assess marker expression. Results Results showed variable expression of melanocytic markers in different anatomical sites, particularly within epidermis of haired skin and dermal melanocytes. Melan A and SOX‐10 were the most specific and sensitive melanocytic markers. PNL2 was less sensitive, while TRP1 and TRP2 were seldomly expressed by intraepidermal melanocytes in haired skin. MITF had a good sensitivity, yet the expression often was weak. Conclusions and Clinical Relevance Our results indicate a variable expression of melanocytic markers in different sites, suggesting the presence of subpopulations of melanocytes. These preliminary results pave the way to understanding the pathogenetic mechanisms involved in degenerative melanocytic disorders and melanoma. Furthermore, the possible different expression of melanocyte markers in different anatomical sites could influence their sensitivity and specificity when used for diagnostic purposes. Résumé Contexte Les mélanoblastes proviennent de la crête neurale, d'où ils migrent vers les tissus périphériques et se différencient en mélanocytes. L'altération des ménanocytes durant leur développement et leur vie peut induire différentes maladies : des troubles pigmentaires et des fonctions visuelles et auditives, ainsi que tumeurs telles que le mélanome. La localisation et les caractéristiques phénotypiques des mélanocytes ont été précisées dans différentes espèces, mais ces données manquent chez le chien. Objectif L'expression des marqueurs mélanocytaires Melan A, PNL2, TRP1, TRP2, SOX‐10 et MITF est étudiée dans des échantillons de peau et de mu