Cocktail Diagnostic Of Immunohistochemical Panel (Atrx, Olig2, Gfap) In The Classification Of Adult-Type Diffuse Gliomas: Comparison With Chromogenic In Situ Hybridization

Abstract

Background: Molecular testing for 1p/19q codeletion using CISH is the gold standard, but it is hampered by high costs, limited facilities, infrastructure, and human resources. A simple and more economical diagnostic method is needed to differentiate adult-type diffuse gliomas. This study aimed to determine the diagnostic value of the IHC cocktail (ATRX, OLIG2, GFAP) in differentiating astrocytomas from oligodendrogliomas based on 1p/19q codeletion status.

Methods: This observational analytical study of diagnostic development used a cross-sectional design. The subjects were paraffin blocks from patients with adult-type diffuse gliomas. Protein expression was analyzed using IHC (ATRX, OLIG2, GFAP) and compared with CISH for 1p/19q codeletion.

Results: Negative ATRX expression had the best diagnostic value with moderate accuracy (55.8%), sensitivity of 56.5%, and specificity of 55.2% in differentiating astrocytoma from oligodendroglioma based on 1p/19q codeletion. The IHC cocktail diagnostic of ATRX (-), OLIG2 <7.5, and GFAP <10.5 had low sensitivity (13.0%) but excellent specificity (96.6%), and moderate accuracy (59.6%) in predicting 1p/19q codeletion.

Conclusion: Cocktail diagnostic (ATRX, OLIG2, and GFAP) showed very high specificity but low sensitivity.