title: Increased MIB-1/Ki-67 labeling index as a predictor of an aggressive course in a case of prolactinoma.
abstract: Secondary resistance to dopamine agonists is a rare phenomenon in patients with a prolactinoma. We describe a 55-year-old male with a macroprolactinoma initially responding favorably to bromocriptine treatment with normalization of prolactin levels and tumor shrinkage. Two years later, he developed resistance to bromocriptine treatment and subsequently to cabergoline. The aggressive course of the disease necessitated three surgical interventions. Staining of the pituitary tissue revealed a very high MIB/Ki-67 labeling index that increased further in specimens derived from repeated surgery. This case demonstrates that high and increasing levels of the MIB/Ki-67 labeling index may indicate an aggressive course associated with secondary dopamine resistance.
authors.affiliation: Division of Endocrinology, Kaplan Medical Center, Hebrew University and Hadassah School of Medicine, Jerusalem, Israel. Lior_zo@zahav.net.il
authors.forename: Taiba
authors.initials: T
authors.lastname: Zornitzki
authors.forename: Hilla
authors.initials: H
authors.lastname: Knobler
authors.forename: Dvora
authors.initials: D
authors.lastname: Nass
authors.forename: Moshe
authors.initials: M
authors.lastname: Hadani
authors.forename: Ilan
authors.initials: I
authors.lastname: Shimon
mesh_terms: D014408:Biomarkers, Tumor / Q000032:analysis; D018450:Disease Progression; D006801:Humans; D019394:Ki-67 Antigen / Q000032:analysis*; D008297:Male; D008875:Middle Aged; D008940:Mitotic Index; D010911:Pituitary Neoplasms / Q000473:pathology* / Q000601:surgery; D011237:Predictive Value of Tests; D015175:Prolactinoma / Q000473:pathology* / Q000601:surgery; D016896:Treatment Outcome
chemical_list: D014408:Biomarkers, Tumor; D019394:Ki-67 Antigen