Several markers were identified, as shown in Figure 4D. The tumor was CK8/18(+), CK7(+), CDX2(−), CK20(−), p63(+), p40(+), TTF1(−), Napsin A(−), Syn(−), Cg-A(−), Ki67(+), and SPA(−), confirming that the tumor was a poorly differentiated squamous carcinoma. The gene discussed is TTF1; the disease is squamous cell carcinoma.