Salivary protein markers: a noninvasive protein profile-based method for the early diagnosis of oral premalignancy and malignancy.

An ultra-sensitive hyphenated technique, high-performance liquid chromatography-laser-induced fluorescence detection protein profiling of saliva, is evaluated for early detection and diagnosis of oral premalignancy and malignancy. Calibration sets of protein profiles of unstimulated whole saliva are collected from clinically/pathologically normal, premalignant, and malignant subjects and used as standards. Three parameters-scores of factors, sum of squared residuals, and Mahalanobis distance-derived from principal component analysis of protein profiles of the standard calibration sets, and blind samples are used for "match/no-match" diagnosis of the blind samples. Analyses of the results show that the method is capable of differentiating normal, premalignant, and malignant conditions with the sensitivity and specificity of 79% and 78%, respectively. The technique provides a fast, highly objective (free from personal judgment and statistically defined), and noninvasive diagnostic method for screening and early detection of oral cancer.