Thyroid transcription factor–1 (TTF-1) expression, routinely assessed through immunohistochemistry in the diagnostic evaluation of lung adenocarcinomas (LUADs), is negative (TTF-1Neg) in approximately 15% to 20% of cases. Although worse outcomes have been reported for these tumors compared with TTF-1–positive (TTF-1Pos) LUAD, a comprehensive characterization of TTF-1 negativity is currently lacking.
Thyroid transcription factor–1 (TTF-1) expression, routinely assessed through immunohistochemistry in the diagnostic evaluation of lung adenocarcinomas (LUADs), is negative (TTF-1Neg) in approximately 15% to 20% of cases. Although worse outcomes have been reported for these tumors compared with TTF-1–positive (TTF-1Pos) LUAD, a comprehensive characterization of TTF-1 negativity is currently lacking.