Thyroid transcription factor-1 in primary CNS tumors

Area of Science:

• Neuropathology
• Molecular Pathology
• Oncology

Background:

• Thyroid transcription factor-1 (TTF-1) is a marker for thyroid and lung cancers.
• Its expression in central nervous system (CNS) tumors is poorly understood, with conflicting results.
• Different antibody clones (8G7G3/1 and SPT24) may explain divergent findings.

Purpose of the Study:

• To investigate TTF-1 expression in a series of CNS tumors.
• To compare the efficacy of TTF-1 antibody clones 8G7G3/1 and SPT24.
• To correlate TTF-1 expression with tumor type and grade.

Main Methods:

• Analysis of 155 CNS tumors using multitissue blocks.
• Optimized protocols for TTF-1 demonstration with clones 8G7G3/1 and SPT24 on Benchmark Ultra stainer.
• Assessment of TTF-1 expression, intensity, and correlation with nestin.

Main Results:

• TTF-1 staining was observed in 13 of 155 CNS tumors (8%) using the SPT24 clone.
• TTF-1 was found in 18% of high-grade (III-IV) astrodendroglial and oligodendroglial tumors, but not in low-grade (I-II) tumors.
• Weak to moderate, focal TTF-1 staining was noted, inversely correlated with nestin. Clone 8G7G3/1 yielded no positive results.

Conclusions:

• TTF-1 expression occurs in a subset of CNS tumors, predominantly high-grade gliomas.
• The SPT24 antibody clone is superior for detecting TTF-1 in CNS neoplasms.
• Consideration of TTF-1 is important for interpreting primary brain tumors of uncertain origin.