In all cases tested, the tumor cells were positive for PAX8 (2/2, diffusely in both) (Figure 5A), GATA3 (4/4, diffusely in two and focally in two) (Figures 5B, C), and TTF1 (3/3, focally in two and diffusely in one) (Figures 5D, E), and the one (case 3) which was diffusely positive for TTF1 also diffusely expressed GATA3. The gene discussed is TTF1; the disease is neoplasm.