Background: Salivary agglutinin, also known as deleted in malignant brain tumors 1 (DMBT1), is an anti-microbial protein. Salivary DMBT1 is low in saliva from patients with oral cancer and dramatically increases after treatment with accompanying microbial changes. While suppression of DMBT1 has been associated with oral microbial dysbiosis and oral cancer, direct effect has not been established.