The influence of staining procedures on the assessment of cell proliferation as defined by the monoclonal antibody Ki-67.
We examined the influence of different staining techniques [(three-step immunoperoxidase technique (IP); alkaline phosphatase-anti-alkaline phosphatase technique (APAAP)] on the quantitative evaluation of Ki-67-labeled nuclei. We studied five melanocytic skin tumors. From each case, five parallel sections were prepared and stained using the peroxidase-antiperoxidase (PAP) technique (slide 1) and the APAAP technique once (slide 2). Slide 3 consisted of a single repetition of the APAAP technique, slide 4 was a double repetition, and slide 5 was a third repetition. We assessed the volume fraction (VV) of Ki-67-positive nuclei using computer-assisted image analysis. For each staining group, the mean value and standard deviation of VV were calculated. Comparing VV values obtained from the different staining groups we did not find a statistically significant difference between the IP and the various APAAP steps (Wilcoxon test, p = less than 0.05). However, the staining procedure influenced the quantitative results to some extent. The mean VV of the five staining groups ranged in our study from 0.10 to 0.17%, which is narrow compared with the overall variability among different cases (dermal melanocytic nevus, 0.01%; metastatic malignant melanoma, 0.43%). Therefore, we can state that for a rough evaluation of Ki-67-positive nuclei, the influence of different staining methods is negligible; for a subtle quantitative analysis, however, it would nevertheless be preferable to always apply the same staining technique.
Department of Dermatology, University of Graz, Austria.
R
R
Hofmann-Wellenhof
J
J
Smolle
H
H
Kerl
D000954:Antigens, Surface / Q000032:analysis*; D002455:Cell Division; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D007124:Immunoenzyme Techniques; D019394:Ki-67 Antigen; D008544:Melanocytes / Q000473:pathology; D008545:Melanoma / Q000378:metabolism / Q000473:pathology*; D009506:Nevus / Q000378:metabolism / Q000473:pathology*; D009687:Nuclear Proteins / Q000032:analysis*; D012878:Skin Neoplasms / Q000378:metabolism / Q000473:pathology*; D013194:Staining and Labeling
D000954:Antigens, Surface; D019394:Ki-67 Antigen; D009687:Nuclear Proteins