Label‐free Microscopic Assessment of Glioblastoma Biopsy Specimens Prior to Biobanking

Abstract

Introduction: Glioblastoma is the most common primary brain tumor with a median 12‐ to 15‐ month patient survival. Improving patient survival involves better understanding the biological mechanisms of glioblastoma tumorigenesis and seeking targeted molecular therapies. Central to furthering these advances is the collection and storage of surgical biopsies (biobanking) for research. We addressed an imaging modality, confocal reflectance microscopy (CRM), for safely screening glioblastoma biopsy samples prior to biobanking to increase the quality of tissue provided for research and clinical trials. We hypothesize that CRM is a safe and effective method for screening specimens prior to biobanking. Methods: Intracranial implantation of human glioma cells was performed to create glioblastoma xenografts. Rodents xenografts were anesthetized to collect whole brain specimens, which were sectioned into tumor containing slices. One set of slices were incubated with DAPI and imaged. A coefficient of determination analysis was then used to compare cells identified with CRM to cells labeled with DAPI. The other set of slices were imaged using CRM at various time points and subsequently frozen for later analysis of DNA, RNA, and protein integrity. We subsequently imaged human glioma biopsies with CRM to determine cellularity and necrosis. Results: CRM provides definitive contrast between cell nuclei, cytoplasm, and extracellular tissue to help identify tumor regions, margins, and acellular regions of animal glioblastoma specimens without altering DNA, RNA, or protein expression of imaged tissue. When imaging fresh human biopsy samples, CRM can differentiate a cellular glioblastoma biopsy from a necrotic biopsy. Conclusion: These data illustrate CRM’s potential for rapidly and safely screening clinical biopsy samples prior to biobanking, which demonstrates its potential as an effective screening technique that can improve the quality of tissue biobanked for patients with glioblastoma.