title: MIB-1 proliferative activity is a significant prognostic factor in primary thick cutaneous melanomas.
abstract: Although the Breslow measurement of tumor thickness of melanoma is the most significant predictor of survival, the biologic behavior of thick lesions remains unpredictable. MIB-1, a monoclonal antibody to a Ki-67 epitope, recognizes all proliferating cells. Unlike Ki-67 antibody, which requires frozen tissue, MIB-1 can be used on formalin-fixed tissue. Proliferation, measured by MIB-1 expression and mitotic index, was assessed as a prognostic factor in a group of patients with clinical stage I thick cutaneous melanoma (tumor thickness 4 mm or greater), for which predicted survival is low. From a melanoma data base, 97 patients with this type of melanoma were identified. Of these, 64 had lesional tissue available for study. The median follow-up time was 3.8 years (range 0.42-13.6 years). The percentage of MIB-1 reactivity was scored as low at less than 10% (n = 33), intermediate at 10% to 20% (n = 17), and high at greater than 20% (n = 14). Melanomas with high MIB-1 reactivity were associated with significantly poorer cause-specific survival compared with tumors with intermediate (p < 0.0001) or low MIB-1 reactivity (p = 0.0025). Multivariate analysis demonstrated that MIB-1 reactivity was a significant independent prognostic factor related to cause-specific survival (p = 0.0002) and was more sensitive than tumor thickness or mitotic index in this select group of high-risk patients. Identification of individuals with stage I thick cutaneous melanoma who are at risk of recurrent disease may improve patient management as new therapeutic modalities become available.
authors.affiliation: Department of Medicine, University of Toronto, Ontario, Canada.
authors.forename: J A
authors.initials: JA
authors.lastname: Ramsay
authors.forename: L
authors.initials: L
authors.lastname: From
authors.forename: N A
authors.initials: NA
authors.lastname: Iscoe
authors.forename: H J
authors.initials: HJ
authors.lastname: Kahn
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000911:Antibodies, Monoclonal / Q000276:immunology*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D019394:Ki-67 Antigen; D008297:Male; D008545:Melanoma / Q000401:mortality / Q000473:pathology*; D008875:Middle Aged; D009363:Neoplasm Proteins / Q000032:analysis*; D009687:Nuclear Proteins / Q000032:analysis*; D011379:Prognosis; D012878:Skin Neoplasms / Q000401:mortality / Q000473:pathology*; D015996:Survival Rate
chemical_list: D000911:Antibodies, Monoclonal; D019394:Ki-67 Antigen; D009363:Neoplasm Proteins; D009687:Nuclear Proteins