In the last 10 years, the use of saliva as a diagnostic fluid has become somewhat of a translational research success story. Technologies are now available enabling saliva to be used to diagnose disease and predict disease progression. This review describes some important recent advances in salivary diagnostics and barriers to application and advancement. This review will also stimulate future research activity.

A panel of markers used to aid in the diagnosis and treatment of breast cancer was examined in the saliva of a cohort of healthy women, women with benign lesions of the breast, and women with diagnosed breast cancer. We found recognized tumor markers c-erbB-2 (erb), cancer antigen 15-3 (CA15-3), and tumor suppressor oncogene protein 53 (p53) in the saliva of all three groups of women. The levels of erb and CA15-3 in the cancer patients evaluated, however, were significantly higher than the salivary levels of healthy control subjects and benign tumor patients. Conversely, pantropic p53 levels were higher in control subjects compared with those women with breast cancer and those with benign tumors. Although cathepsin-D and epidermal growth factor receptor were detected, they did not demonstrate any clear correlation with disease status. The results of the pilot suggest that these markers have potential use in initial detection and/or follow-up screening for the detection of breast cancer in women.

The study suggests that saliva is a fluid suffused with solubilized by-products of oncogenic expression and that these proteins may be modulated secondary to DCIS. Additionally, there may be salivary protein profiles that are unique to both DCIS and fibroadenoma tumors.

A surge of new technological developments, coupled with the limitations of existing disease-detection methodologies, is propelling the field of medical diagnostics forward at unprecedented rates. Advancements in proteomics and nanotechnology are paving the way for diagnostic tests that will be capable of rapid multi-analyte detection in both laboratory and non-laboratory settings. Technological advancements have also benefited biomarker research to the point where saliva is now recognized as an excellent diagnostic medium that can be collected simply and non-invasively. Salivary biomarkers have been identified that may provide diagnostic information about a variety of cancers and other diseases. In particular, proof-of-principle has been demonstrated for salivary c-erbB-2, whose elevation has been shown to correlate strongly with breast malignancy in women. The purpose of this manuscript is to review the past literature and present the current research focused on the use of saliva as a diagnostic medium for the detection of malignancies that are remote from the oral cavity.

The study suggests that saliva may be useful for high-throughput biomarker discovery.