TP53 and neoplasm: Both of the tumor cells were diffuse and strongly positive for TTF1 (Fig. 3A, B), Napsin A (Fig. 3C, D), EMA and CK7, and the proliferation index KI-67 was less than 5% (Fig. 3E, F), with P53 showing wild-type expression patterns and negative for CEA, C-myc and P63.