TTF1 and cancer: To better distinguish the cancer tissue from the surrounding tissue, we finally stained with p63 and TTF-1 as lung cancer cell specific markers16 and found that all the two SCC cases showed strong positive staining for p63 (Fig. 4A), and not one of adenocarcinomas samples was positive (Fig. 4B), but TTF-1 staining was observed in 60.0% of adenocarcinomas (Fig. 4D and Table S2).