Fig. 1a. Metastatic thyroid follicular carcinoma stained for TTF-1.

Fig. 1b. Pulmonary adenocarcinoma stained for TTF-1.

Fig. 1c. Mucinous bronchioloalveolar carcinoma stained for TTF-1. The tumour (right) is negative, while the normal alveolar cells (left) are strongly stained.

Fig. 1d. Liver with metastatic lung small cell carcinoma stained for TTF-1, using mAb clone 8G7G3/1. The tumour cells show strong nuclear staining while the liver cells show a cytoplasmic reaction.