86% of GNAS-mutated non-mucinous adenocarcinomas (6/7) were positive for TTF-1 immunohistochemistry, while only 25% of GNAS-mutated IMAs (1/4) were positive for TTF-1.
Mucinous adenocarcinoma of the lung is a subtype of highly invasive pulmonary tumors and is associated with decreased or absent expression of the transcription factor NK2 homeobox 1 (NKX2-1; also known as TTF-1).