Reassessing the Reliability of Ki-67 as an Indicator of Pituitary Neuroendocrine Tumor Progression: Based on Cell Lineage Categorization

Abstract

Background: The role of KI-67, a tumor proliferation marker, as a biomarker for progression in pituitary neuroendocrine tumors (PitNETs) remains controversial. The aim of this study was to analyze the relationship between KI-67 expression levels and PitNETs progression based on transcriptional factor lineage classification. Methods: A total of 97 PitNETs patients who underwent endoscopic surgery performed by the same surgeon between February 2022 and March 2023 were included in the study. Immunohistochemistry was used to stain tumor specimens for KI-67. Tumor progression was assessed based on Knosp classification and follow-up results, and separate analyses were performed according to hormone secretion status and transcriptional factor lineage classification. Results: We found no significant differences in preoperative tumor characteristics and various prognostic outcomes between patients with high and low KI-67 expression. When classified according to hormone secretion types, no significant differences were observed in the progression of various PitNETs and KI-67. However, when classified based on tumor transcriptional factor lineages, a significant association with invasiveness was observed in the T-PIT lineage with high KI-67 expression (P = 0.035), but not in the PIT-1 and SF-1 lineages. Conclusion: The research has found that KI-67 as a biomarker for tumor progression in PitNETs is unreliable. emphasizing the importance of comprehensively considering pitNETs subtypes and molecular characteristics in patient assessment.