Rapid polymer-based immunohistochemistry for intraoperative CNS tumor diagnosis: A validation study

Area of Science:

• Neuropathology
• Oncology
• Surgical Pathology

Background:

• Intraoperative diagnostics in neuro-oncology are limited by slow conventional methods.
• Distinguishing brain tumors like gliomas, metastases, and lymphomas during surgery is challenging.
• There's a need for rapid diagnostic tools to guide real-time surgical decisions.

Purpose of the Study:

• To validate a novel, rapid immunohistochemistry (IHC) protocol for intraoperative neuro-oncology.
• To assess the feasibility of achieving results in under 30 minutes.
• To evaluate the diagnostic utility of this rapid IHC for central nervous system (CNS) tumors.

Main Methods:

• A new IHC protocol using directly conjugated polymerized horseradish peroxidase (pHRP) antibodies was developed.
• The protocol was tested on 115 intraoperative frozen tissue samples from neuro-oncology patients.
• Performance of pan-cytokeratin (pan-CK), glial fibrillary acidic protein (GFAP), and CD20 antibodies was evaluated using a 4-tiered scoring system.

Main Results:

• The rapid IHC protocol successfully provided results in under 30 minutes.
• Cytoplasmic markers GFAP and pan-CK showed high reliability with mean scores of 2.6 and 2.47.
• Over 68% of cases exhibited strong (3+) staining for GFAP and pan-CK.
• The membrane-bound marker CD20 showed more variability (mean score 2.07).

Conclusions:

• The rapid IHC method is effective for intraoperative differentiation of CNS tumors, especially those with cytoplasmic antigens.
• This technique offers near real-time diagnostic information, enhancing surgical precision.
• The rapid protocol has the potential to improve patient outcomes through timely therapeutic strategies.