Inter-laboratory comparison of Ki-67 proliferating index detected by visual assessment and automated digital image analysis.

BACKGROUND: Proliferation rate is a major determinant of the biologic behavior of the tumor and provides information that can be used to guide treatment decisions. METHODS: This ring study included 27 pathologists from 14 Institutions, in order to assess inter-observer concordance between pathologists in Croatia. We analyzed Ki-67 proliferative index on ten randomly selected breast cancer samples comparing consistency between visual assessment using light microscopy compared to digital image analyses results from one central laboratory as a referral value. RESULTS: When we analyzed Ki-67 as numeric value high concordance rate was found between Ki-67 score visually assessed in all participating Institutions compared to referral value assessed by digital image analysis (ICC 0.76, 95% CI 0.58-0.91), and Krippendorff's alpha was 0.79 (95% CI 0.58-1.00). Concordance was better in slides with higher Ki-67 values. When we categorized Ki-67 values according to generally accepted 20% cut-off value we noticed the lower concordance rate among participants in our study. CONCLUSION: Proliferation remains one of the most important parameters for tumor characterization helpful in making clinical decisions, but it should be used with great caution. Standardization of the Ki-67 assessment is essential and proliferating index should be expressed as exact numeric value. For patients with proliferative index near the cut-off value, other factors must be considered in making clinical decisions.

Assessment of apoptosis in the native vein used for hemodialysis access.

AIM: To determine whether apoptosis is more common in previously punctured native veins than in non-punctured native veins among patients who undergo surgical creation of arteriovenous fistula (AVF) for dialysis access. METHODS: Cephalic vein specimens were obtained from January 1, 2013 to December 31, 2014 from 60 patients, 30 with previously punctured native veins and 30 with non-punctured native veins. Before AVF placement, a 1-cm vein segment was excised from distal part of the vein for histological, histochemical, and immunohistochemical analysis. Vein specimens were divided into two portions along the longitudinal axis and stained with hematoxylin and eosin for routine histological evaluation. Immunohistochemical analysis was used to localize Bax, p53, caspase 3, and Bcl-2 expression. RESULTS: The group with previously punctured veins showed significantly increased caspase 3 (P<0.001, two-sided Fisher`s Exact Test) and Bax expression (P=0.002, two-sided Fisher`s Exact Test) and significantly decreased Bcl-2 expression (P<0.001, two-sided Fisher`s Exact Test) compared with the control group. There were no significant differences between the groups in p53 expression (?2=0.071, df=1, P=0.791). Fistula failure was significantly more common in the study group (26.7% vs 6.7%, ?2=4.32, df=1, P=0.038). CONCLUSION: Our study indicates a possible role of venipuncture in apoptosis development and a possible role of apoptosis in fistula failure, but we do not have sufficient evidence to conclude that it represents its main cause.