Quantitative Assessment of Preanalytic Variables on Clinical Evaluation of PI3/AKT/mTOR Signaling Activity in Diffuse Glioma.

Autor:	Beccari S; Department of Neurological Surgery, University of California, San Francisco, California., Mohamed E; Department of Neurological Surgery, University of California, San Francisco, California., Voong V; Department of Neurological Surgery, University of California, San Francisco, California., Hilz S; Department of Neurological Surgery, University of California, San Francisco, California., Lafontaine M; Department of Radiology and Biomedical Imaging, University of California, San Francisco, California., Shai A; Department of Neurological Surgery, University of California, San Francisco, California., Lim Y; Department of Neurological Surgery, University of California, San Francisco, California., Martinez J; Department of Neurological Surgery, University of California, San Francisco, California., Switzman B; Department of Neurological Surgery, University of California, San Francisco, California., Yu RL; Department of Neurological Surgery, University of California, San Francisco, California., Lupo JM; Department of Radiology and Biomedical Imaging, University of California, San Francisco, California., Chang EF; Department of Neurological Surgery, University of California, San Francisco, California., Hervey-Jumper SL; Department of Neurological Surgery, University of California, San Francisco, California., Berger MS; Department of Neurological Surgery, University of California, San Francisco, California., Costello JF; Department of Neurological Surgery, University of California, San Francisco, California., Phillips JJ; Department of Neurological Surgery, University of California, San Francisco, California; Neuropathology Division, Department of Pathology, University of California, San Francisco, California. Electronic address: Joanna.phillips@ucsf.edu.
Jazyk:	angličtina
Zdroj:	Modern pathology : an official journal of the United States and Canadian Academy of Pathology, Inc [Mod Pathol] 2024 Jun; Vol. 37 (6), pp. 100488. Date of Electronic Publication: 2024 Apr 06.
DOI:	10.1016/j.modpat.2024.100488
Abstrakt:	Biomarker-driven therapeutic clinical trials require the implementation of standardized, evidence-based practices for sample collection. In diffuse glioma, phosphatidylinositol 3 (PI3)-kinase/AKT/mTOR (PI3/AKT/mTOR) signaling is an attractive therapeutic target for which window-of-opportunity clinical trials could facilitate the identification of promising new agents. Yet, the relevant preanalytic variables and optimal tumor sampling methods necessary to measure pathway activity are unknown. To address this, we used a murine model for isocitrate dehydrogenase (IDH)-wildtype glioblastoma (GBM) and human tumor tissue, including IDH-wildtype GBM and IDH-mutant diffuse glioma. First, we determined the impact of delayed time-to-formalin fixation, or cold ischemia time (CIT), on the quantitative assessment of cellular expression of 6 phosphoproteins that are readouts of PI3K/AK/mTOR activity (phosphorylated-proline-rich Akt substrate of 40 kDa (p-PRAS40, T246), -mechanistic target of rapamycin (p-mTOR; S2448); -AKT (p-AKT, S473); -ribosomal protein S6 (p-RPS6, S240/244 and S235/236), and -eukaryotic initiation factor 4E-binding protein 1 (p-4EBP1, T37/46). With CITs ≥ 2 hours, typical of routine clinical handling, all had reduced or altered expression with p-RPS6 (S240/244) exhibiting relatively greater stability. A similar pattern was observed using patient tumor samples from the operating room with p-4EBP1 more sensitive to delayed fixation than p-RPS6 (S240/244). Many clinical trials utilize unstained slides for biomarker evaluation. Thus, we evaluated the impact of slide storage conditions on the detection of p-RPS6 (S240/244), p-4EBP1, and p-AKT. After 5 months, storage at -80°C was required to preserve the expression of p-4EBP1 and p-AKT, whereas p-RPS6 (240/244) expression was not stable regardless of storage temperature. Biomarker heterogeneity impacts optimal tumor sampling. Quantification of p-RPS6 (240/244) expression in multiple regionally distinct human tumor samples from 8 patients revealed significant intratumoral heterogeneity. Thus, the accurate assessment of PI3K/AKT/mTOR signaling in diffuse glioma must overcome intratumoral heterogeneity and multiple preanalytic factors, including time-to-formalin fixation, slide storage conditions, and phosphoprotein of interest. (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)
Databáze:	MEDLINE
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