Among the seven proteins investigated in saliva, six proteins, including CSTB, LTA4H, PGKI, NDRG1, COL6A1, and ITGAV, showed lower abundances in the saliva of the patients with lymph node metastasis (N+) than the patients without lymph node metastasis (N0) (Mann−Whitney U test, with P values adjusted for multiple comparisons using the Benjamini−Hochberg FDR method, adj. Here, NDRG1 is linked to metastatic malignant neoplasm in the lymph nodes.