Salivary protein factors are elevated in breast cancer patients

While saliva is a source of easily accessible bodily fluids, there has been little effort to study its value in cancer diagnosis. We hypothesized that certain proteins would be elevated in the saliva of patients with breast cancer. Our study included 49 healthy individuals and 49 breast cancer patients. The levels of vascular endothelial growth factor (VEGF), epidermal growth factor (EGF) and carcinoembryonic antigen (CEA) in the saliva were measured with enzyme-linked immunosorbent assay (ELISA). We observed that salivary fluid protein levels were significantly elevated in cancer patients as follows: i) VEGF, 3.7±1.6 in cancer versus 2.1±1.2 ng/ml in control (p<0.0001); ii) EGF, 3.7±1.7 versus 2.1±1.3 ng/ml (p<0.0001); and iii) CEA, 83±31 versus 66.1±27.1 ng/ml (p=0.0106). The areas under the receiver operating characteristic (ROC) curve (AUC) were 80, 77 and 65%, respectively. The best prediction was from the combination of salivary VEGF and EGF with a sensitivity of 83%, specificity of 74% and AUC of 84%. We conclude that saliva is a novel avenue for tumor marker research and deserves further studies. Saliva may potentially be useful in supplementing current methods of breast cancer detection.