Good staining quality ensuring the reproducibility of Ki67 assessment
Journal
Journal of Clinical Pathology
Date Issued
2019
Author(s)
Abstract
Aims Although Ki67 labelling index (LI) is a prognostic and predictive marker in breast cancer, its accuracy and reproducibility must be validated before its clinical application. We aimed to evaluate the agreement of Ki67 LI in clinical practice in Taiwan. Methods We conducted a Ki67 immunohistochemistry (IHC) proficiency test. The participants performed the Ki67 IHC test and measured the Ki67 LI of 10 cases of breast cancer tissue on a microarray slide. The staining quality was centrally reviewed based on the Ki67 staining of the tonsil surface epithelium. Results Ki67 staining and counting methods are diverse in Taiwan. The reproducibility of Ki67 LI was poor to good (intraclass correlation coefficient: 0.581, 95% CI 0.354 to 0.802). The reproducibility and agreement in the high staining quality group were significantly higher than those in the low staining quality group. The majority of the Ki67 LIs derived from the low staining quality group were underestimated. Different counting methods did not reveal significant differences when determining Ki67 LI with microarray sections. Conclusions We suggest using the surface epithelium of the tonsil as external control and achieving optimal staining results that consist of a high positive parabasal layer, a low positive intermediate layer and a negative superficial layer. Good Ki67 staining quality can minimise the staining variations among different laboratories, and it is essential for the reproducibility of Ki67 LI. ? Author(s) (or their employer(s)) 2020. No commercial re-use. See rights and permissions. Published by BMJ.
Subjects
breast cancer; immunohistochemistry; KI 67; quality control
Other Subjects
Ki 67 antigen; Ki 67 antigen; MKI67 protein, human; Article; cell count; clinical practice; epithelium; immunohistochemistry; labeling index; microarray analysis; priority journal; reproducibility; staining; Taiwan; breast tumor; female; good laboratory practice; human; medical society; metabolism; pathology; procedures; prognosis; staining; Breast Neoplasms; Female; Humans; Immunohistochemistry; Ki-67 Antigen; Laboratory Proficiency Testing; Prognosis; Reproducibility of Results; Societies, Medical; Staining and Labeling; Taiwan
Publisher
BMJ Publishing Group
Type
journal article