The rate of normal NKD1 expression in squamous carcinoma (13/33, 39.4%) was higher than that in adenocarcinoma (9/67, 13.4%) (P = 0.003); the rate of normal NKD1 in stages I-II (16/44, 36.3%) was higher than in stages III-IV (6/56, 10.7%) (P = 0.002); and the rate was also higher in cases without lymphatic metastasis (15/45, 33.3%) than in cases with lymphatic metastasis (7/55, 12.7%) (P = 0.013). Here, NKD1 is linked to squamous cell carcinoma.