Phosphohistone H3 and Ki-67 Labeling Indices in Cytologic Specimens from Well-Differentiated Neuroendocrine Tumors of the Gastrointestinal Tract and Pancreas: A Comparative Analysis Using Automated Image Cytometry

Abstract

Background: Ki-67 proliferation index was recently incorporated in the grading of neuroendocrine neoplasms (NENs) of the gastrointestinal tract (GIT) and pancreas. These are now divided into well-differentiated neuroendocrine tumors (WDNETs, grades 1 and 2) and poorly differentiated neuroendocrine carcinomas (grade 3). While Ki-67 is an established proliferation marker in NENs, phosphohistone H3 (PHH3), a newer marker of mitotic activity, is not. Methods: We determined Ki-67 and PHH3 indices on cytologic samples from WDNETs of the GIT and pancreas using an automated cellular imaging system (ACIS®). Results: There was a strong correlation between Ki-67 and PHH3 indices generated by ACIS on cytologic samples. However, in some cases the two stains caused conflicting grades within the same tumor. Conclusion: Both antibodies stain cells in different phases of the cell cycle which may cause discordant grades, thus affecting patient management and prognostication. Ki-67 staining is stronger than PHH3, making ‘hot spots' easier to identify on ACIS. Ki-67 is more ideal than PHH3 for staining NENs, especially in tumors with borderline grades. Because PHH3 generates lower mitotic indices it should not be used as a proliferation marker in NENs until its expression has been further characterized.

Calculation of the Ki67 index in pancreatic neuroendocrine tumors: a comparative analysis of four counting methodologies

“…Although this method has been advocated as the ‘gold standard’ for Ki67 calculation, with the idea that the count can be performed accurately by the instrument, 12,16–18 our study and others 19,20 highlighted several shortcomings in its presumed accuracy. First, we noted a relative inability of the instrument to distinguish Ki67-positive tumor cells from other Ki67-labeling cell types unless it was manually calibrated to disregard such non-tumor cells, with the application of special software.…”

“…First, intratumoral heterogeneity (a known problem with pancreatic neuroendocrine tumors), as well as the subjectivity of hot spot selection, can lead to marked variation in tumor grade. 7,17–19,21 The issue of whether to interpret pale brown tumor nuclei as positive is another vexing point. For this, a comparison with background nonneoplastic tissue may be helpful as stromal cells should not stain positively if the assay is correctly performed; in a similar manner, we subscribe to the view that light brown nuclei should generally be disregarded.…”

Effect of prenatal exposure to bisphenol a on the vagina of albino rats: immunohistochemical and ultrastructural study

“…High doses of BPA have induced cell-transforming activities and aneuploidy in Syrian hamster embryo cells, suggesting that it has the potential to be genotoxic [35]. Antigen Ki-67 is a nuclear protein that is associated with cellular proliferation [7]. This means that these areas were subjected to kinds of unusual stresses which induced proliferative changes hampered by degenerative ones.…”

Erratum: Calculation of the Ki67 index in pancreatic neuroendocrine tumors: a comparative analysis of four counting methodologies

“…Although this method has been advocated as the 'gold standard' for Ki67 calculation, with the idea that the count can be performed accurately by the instrument, 12,16-18 our study and others 19,20 highlighted several shortcomings in its presumed accuracy. First, we noted a relative inability of the instrument to distinguish Ki67-positive tumor cells from other Ki67-labeling cell types unless it was manually calibrated to disregard such non-tumor cells, with the application of special software.…”

“…First, intratumoral heterogeneity (a known problem with pancreatic neuroendocrine tumors), as well as the subjectivity of hot spot selection, can lead to marked variation in tumor grade. 7,[17][18][19]21 The issue of whether to interpret pale brown tumor nuclei as positive is another vexing point. For this, a comparison with background nonneoplastic tissue may be helpful as stromal cells should not stain positively if the assay is correctly performed; in a similar manner, we subscribe to the view that light brown nuclei should generally be disregarded.…”