title: The p16-Ki-67-HMB45 Immunohistochemistry Scoring System is Highly Concordant With the Fluorescent In Situ Hybridization Test to Differentiate Between Melanocytic Nevi and Melanomas.
abstract: The treatment of melanoma requires early diagnosis and extensive surgical removal of the primary tumor. The differential diagnosis between a melanoma and a nevus is sometimes difficult from a histopathologic point of view and could require ancillary diagnostic tools. Recently, both fluorescent in situ hybridization (FISH) and p16-Ki67-HMB45 combined immunohistochemistry have been proposed as examples of ancillary diagnostic methods to help classify melanocytic tumors as benign or malignant. In this study, we compare FISH and p16-Ki-67-HMB45 immunohistochemistry in a set of melanomas and nevi. A total of 101 formalin-fixed and paraffin-embedded tumor samples (44 melanomas and 57 nevi) were analyzed using FISH for chromosomes 6, 8, 9, and 11 and p16-Ki-67-HMB45 immunohistochemistry. Any chromosomal imbalances and/or a p16-Ki-67-HMB45 immunohistochemistry combined score of 4 or higher were considered to reflect a "favor" malignant tumor. Using FISH, 42 out of 44 melanomas presented at least 1 chromosomal imbalance, whereas 2 melanomas and all nevi did not. Each melanoma, including 6 challenging tumors, had a p16-Ki-67-HMB45 immunohistochemistry combined score of 4 or higher and every nevus had a score inferior to 4. This reflects an excellent strength of agreement between FISH, immunohistochemistry, and definitive histopathologic diagnosis in our tumor set. We conclude that both FISH and p16-Ki67-HMB45 combined immunohistochemistry are valuable ancillary diagnostic tools to help pathologists classify melanocytic tumors as nevi or melanomas.
authors.affiliation: Inserm, U1078.|Brest University Hospital, Department of Pathology.|European University of Brittany.
authors.forename: Arnaud
authors.initials: A
authors.lastname: Uguen
authors.affiliation: Brest University Hospital, Department of Pathology.
authors.forename: Marie
authors.initials: M
authors.lastname: Uguen
authors.affiliation: Brest University Hospital, Department of Pathology.
authors.forename: Briac
authors.initials: B
authors.lastname: Guibourg
authors.affiliation: Brest University Hospital, Department of Pathology.|European University of Brittany.|Brest Medecine School.
authors.forename: Matthieu
authors.initials: M
authors.lastname: Talagas
authors.affiliation: Brest University Hospital, Department of Pathology.|European University of Brittany.|Brest Medecine School.
authors.forename: Pascale
authors.initials: P
authors.lastname: Marcorelles
authors.affiliation: Inserm, U1078.|European University of Brittany.|Brest University Hospital, Department of Cytogenetics and Reproduction Biology, Brest, France.
authors.forename: Marc
authors.initials: M
authors.lastname: De Braekeleer
mesh_terms: D014408:Biomarkers, Tumor / Q000378:metabolism; D025063:Chromosome Disorders; D019941:Cyclin-Dependent Kinase Inhibitor p16 / Q000235:genetics / Q000378:metabolism; D003937:Diagnosis, Differential; D055088:Early Detection of Cancer; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods*; D017404:In Situ Hybridization, Fluorescence / Q000379:methods*; D019394:Ki-67 Antigen / Q000235:genetics / Q000378:metabolism; D008545:Melanoma / Q000175:diagnosis*; D058950:Melanoma-Specific Antigens / Q000235:genetics / Q000378:metabolism; D009508:Nevus, Pigmented / Q000175:diagnosis*; D015588:Observer Variation; D012878:Skin Neoplasms / Q000175:diagnosis*; D058951:gp100 Melanoma Antigen
chemical_list: D014408:Biomarkers, Tumor; C000614131:CDKN2A protein, human; D019941:Cyclin-Dependent Kinase Inhibitor p16; D019394:Ki-67 Antigen; D058950:Melanoma-Specific Antigens; C548637:PMEL protein, human; D058951:gp100 Melanoma Antigen