title: MIB-1 immunostaining on cytological samples: a protocol without antigen retrieval.
abstract: The aim of the study was to evaluate the effect of fixation procedures on MIB-1 immunostaining on microwave-treated Papanicolaou-stained slides and to establish protocol for MIB-1 immunostaining on cytological samples without microwave pre-treatment. Cytospins for immunostaining and nuclear suspension for DNA measurement were prepared from human breast cancer cell line (MCF-7). Following fixation, the cytospins were either stained by Papanicolaou, stored in methanol or air-dried. Antigen retrieval by microwave was used before MIB-1 immunostaining only for Papanicolaou-stained cytospins. Air-dried cytospins and cytospins stored in methanol were immunostained without pre-treatment. The percentage of MIB-1 positive cells was compared with the S phase fraction of MCF-7 cells calculated from DNA histograms. Variations in fixation procedures used before Papanicolaou staining had no influence on the percentage of MIB-1 positive cells. The difference between the percentage of the MIB-1-positive cells on microwave-treated Papanicolaou-stained cytospins and on methanol-fixed cytospins without microwave pre-treatment was not significant. There was a strong correlation between the percentage of the MIB-1-positive cells and S phase fraction. Monoclonal antibody MIB-1 recognized Ki-67 antigen in Papanicolaou-stained cytospins treated by microwave as well as in cytospins that were fixed and stored in methanol without microwave pre-treatment.
authors.affiliation: Department of Cytopathology, Institute of Oncology, Zaloska, Ljubljana, Slovenia. ikirbis@onko-i.si
authors.forename: I Srebotnik
authors.initials: IS
authors.lastname: Kirbis
authors.forename: M Strojan
authors.initials: MS
authors.lastname: Flezar
authors.forename: M Us
authors.initials: MU
authors.lastname: Krasovec
mesh_terms: D045744:Cell Line, Tumor; D005260:Female; D016591:Histocytological Preparation Techniques; D006801:Humans; D007150:Immunohistochemistry; D019394:Ki-67 Antigen / Q000737:chemistry* / Q000378:metabolism*; D008872:Microwaves
chemical_list: D019394:Ki-67 Antigen