Gastroscopic biopsy pathology showed: adenocarcinoma in the fundus near the cardia, immunohistochemistry CDX2(−), CK20(−), CK7(+), NapsinA(+), TTF-1(+), Villin(−), and lung adenocarcinoma metastasis was considered in combination with medical history and immunohistochemistry (Fig. 1b). This evidence concerns the gene TTF1 and lung adenocarcinoma.