Which marker is NOT part of the IHC panel for astrocytomas?

• A. GFAP
• B. NFP
• C. p53
• D. CEA

Answer: (D)

Immunohistochemistry panels for astrocytomas focus on confirming glial origin and identifying mutations common in these tumors. GFAP is a classic marker of astrocytic cells, so it’s routinely used to demonstrate astrocytoma lineage. p53 staining can reflect TP53 mutations that occur in some astrocytomas, making it a useful part of the panel for characterization. Neurofilament protein isn’t a standard marker for astrocytomas, though it can help in certain differential diagnoses; it’s not routinely included to define astrocytoma identity. Carcinoembryonic antigen (CEA), however, is a marker tied to epithelial cancers and is not used to characterize glial tumors. So CEA is not part of the typical IHC panel for astrocytomas.