Anatomic Pathology: Immunopathology

• Carcinomas of the lung are generally cytokeratin 7 (CK7) positive and CK20 negative , with a variable proportion expressing thyroid transcription factor-1 (TTF-1).

• Almost all small cell lung carcinomas are TTF-1 positive, a majority of adenocarcinomas are TTF-1 positive, and tumors with squamous differentiation are generally negative.

• Most lung carcinomas are CDX2 negative, except for mucinous pulmonary adenocarcinomas.

Chu PG, Weiss LM: Keratin expression in human tissues and neoplasms. Histopathology 2002;40:403-439.

* = Required 
* Note Title
* Note