TTF1 and adenocarcinoma: TTF1 (thyroid transcription factor 1), which is a commercially known marker for a subtype of NSCLC (adenocarcinoma) and had shown positive expression in mouse lungs, was highly positive in urethane-induced NSCLC (see Figure 8D), while p53 expression was negative in our urethane-induced lung cancer model (see Figure 8B).