The high reactivity rate in pulmonary adenocarcinomas disagrees with the results obtained with histologic sections from solid tumor tissue, and CK5/6 seems to be of very limited value as an additional marker in effusion cytology.

the percentage of lung carcinoma patients remaining unclassifiable by TTF-1/TP63 was twice that of the five-antibody (TRIM29, CEACAM5, SLC7A5, MUC1, and CK5/6) test

Immunohistochemical staining using a combination of TTF-1, napsin A, p63, and CK5/6 allows subclassification of poorly differentiated non-small cell carcinomas on small lung biopsies in most cases.

CK5/6, IMP3 and TTF1 immunostaining appears to be useful to improve the accuracy of cytological diagnoses between reactive mesothelial cells, metastatic adenocarcinoma of lung and non-lung origin in pleural effusion.