title: RACK1, a clue to the diagnosis of cutaneous melanomas in horses.
abstract: BACKGROUND
  Melanocytic proliferations are common in horses but the diagnosis of malignancy is not always straightforward. To improve diagnosis and prognosis, markers of malignancy are needed. Receptor for activated C kinase 1 (RACK1) protein may be such a marker. RACK1 was originally found to characterize malignant melanocytic lesions in the Melanoblastoma-bearing Libechov minipig (MeLiM) and, later, in human patients. Our purpose was to investigate the value of RACK1 in the classification of cutaneous melanocytic proliferations in horses.
  
  
  RESULTS
  Using immunofluorescence, we report here that both MITF (Microphthalmia-associated transcription factor) and PAX3 (Paired box 3) allow the identification of melanocytic cells in horse skin samples. Importantly, RACK1 was detected in melanocytic lesions but not in healthy skin melanocytes. Finally, we found that RACK1 labeling can be used in horses to distinguish benign melanocytic tumors from melanomas. Indeed, RACK1 labeling appeared more informative to assess malignancy than individual histomorphological features.
  
  
  CONCLUSIONS
  This study confirms that horses provide an interesting model for melanoma genesis studies. It establishes MITF and PAX3 as markers of horse melanocytic cells. RACK1 emerges as an important marker of malignancy which may contribute to progress in the diagnosis of melanomas in both human and veterinary medicine.
authors: INRA, UMR955 de Génétique fonctionnelle et médicale, Ecole Nationale Vétérinaire d'Alfort, 7 avenue du Général de Gaulle, Maisons-Alfort, F-94704, France.
authors: Cécile
authors: C
authors: Campagne
authors: Sophia
authors: S
authors: Julé
authors: Florence
authors: F
authors: Bernex
authors: Mercedes
authors: M
authors: Estrada
authors: Geneviève
authors: G
authors: Aubin-Houzelstein
authors: Jean-Jacques
authors: JJ
authors: Panthier
authors: Giorgia
authors: G
authors: Egidy
mesh_terms: D000818:Animals; D014408:Biomarkers, Tumor / Q000097:blood / Q000378:metabolism; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006734:Horse Diseases / Q000175:diagnosis* / Q000378:metabolism; D006736:Horses; D008297:Male; D008545:Melanoma / Q000175:diagnosis / Q000378:metabolism / Q000662:veterinary*; D010455:Peptides / Q000235:genetics / Q000378:metabolism*; D000075370:Receptors for Activated C Kinase; D012878:Skin Neoplasms / Q000175:diagnosis / Q000378:metabolism / Q000662:veterinary*
chemical_list: D014408:Biomarkers, Tumor; D010455:Peptides; D000075370:Receptors for Activated C Kinase; C070301:peptide I