title: Immunohistochemical markers for distinguishing Spitz nevi from malignant melanomas.
abstract: In this study, we demonstrate that immunostaining with MIB-1 and anti-bcl-2 is a useful tool to distinguish compound Spitz nevi from malignant melanomas. Forty-six cases of Spitz nevi and 50 cases of vertical growth-phase melanomas (Clark III-V) were compared for the immunoreactivity of MIB-1 and bcl-2 in the intradermal component of the lesions. As many as 76% of the Spitz nevus cases showed a low percentage (0-2%) of MIB-1 immunoreactivity. In the malignant melanomas, such a low MIB-1 index was shown in only 2% of the cases. The average MIB-1 index in malignant melanomas and Spitz nevi was 29.7 and 4.0%, respectively. bcl-2 was negative in only 4% of the melanoma cases, whereas the corresponding value was 72% in Spitz nevi. Statistical analyses using Students t test showed that the differences were highly significant (P < 0.001). By considering the immunoreactivity for MIB-1 and bcl-2 in the individual cases, we found that as many as 96% of the melanomas both expressed a bcl-2 positivity and exhibited a MIB-1 index exceeding 2% in the dermal component. The corresponding value was as low as 6% in the Spitz nevi.
authors.affiliation: Department of Tumor Pathology, Karolinska Institutet, Stockholm, Sweden.
authors.forename: L
authors.initials: L
authors.lastname: Kanter-Lewensohn
authors.forename: M A
authors.initials: MA
authors.lastname: Hedblad
authors.forename: J
authors.initials: J
authors.lastname: Wejde
authors.forename: O
authors.initials: O
authors.lastname: Larsson
mesh_terms: D034961:Antigens, Nuclear; D014408:Biomarkers, Tumor / Q000032:analysis; D006801:Humans; D007150:Immunohistochemistry; D019394:Ki-67 Antigen; D008545:Melanoma / Q000737:chemistry*; D018332:Nevus, Epithelioid and Spindle Cell / Q000737:chemistry*; D009687:Nuclear Proteins / Q000032:analysis*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000032:analysis*; D012878:Skin Neoplasms / Q000737:chemistry*; D016159:Tumor Suppressor Protein p53 / Q000032:analysis
chemical_list: D034961:Antigens, Nuclear; D014408:Biomarkers, Tumor; D019394:Ki-67 Antigen; D009687:Nuclear Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D016159:Tumor Suppressor Protein p53