Defining Salivary Biomarkers Using Mass Spectrometry-Based Proteomics: A Systematic Review

Abstract

Recent advancements in mass spectrometric proteomics provide a promising result in utilizing saliva to explore biomarkers for diagnostic purposes. However, the issues of specificity or redundancy of disease-associated salivary biomarkers have not been described. This systematic review was therefore aimed to define and summarize disease-related salivary biomarkers identified by mass spectrometry proteomics. Peer-reviewed articles published through July 2009 within three databases were reviewed. Out of 243 articles, 21 studies were selected in this systematic review with conditions including Sjö gren's syndrome, squamous cell carcinoma, dental caries, diabetes, breast cancer, periodontitis, gastric cancer, systemic sclerosis, oral lichen planus, bleeding oral cavity, and graft-versus-host disease. The sample size ranged from 3-41 in both diseased and control subjects, with no consensus on sample collection protocol. One hundred eighty biomarkers were identified in total; 87 upregulated, 63 downregulated, and 30 varying based on disease. Except for Sjö gren's syndrome, the majority of studies with the same disease produce inconsistent biomarkers. Larger sample size and standardization of sample collection/treatment protocol may improve future studies.

The Use of Electrophoresis for the Study of Saliva Involvement in Ingestive Behavior

“…Accurate examination of salivary components requires optimal collection, processing and storage conditions and, as such, there is a need for standardized protocols [55,56]. Salivary secretion is mainly regulated by the two branches of the autonomic nervous system (both sympathetic and parasympathetic), and as such it presents some plasticity, changing in amount and composition according to the nature of the stimulus.…”

“…For both humans and animals, it has been observed that 2DE is the most popular technique for the global analysis and initial profiling of saliva, being used as a first step for protein separation, followed by mass spectrometry (MS) or tandem MS (MS/MS) [82]. 2DE simultaneously separates proteins according to their isoelectric points (pI) and molecular masses, enabling the visualisation and identification of several thousand proteins on a single gel.…”

Magnetic Bead-Based Salivary Peptidome Profiling Analysis for Severe Early Childhood Caries

“…Thus, the relationship between dental caries and human salivary proteins is not well defined, and biomarker information remains unclear. Moreover, no studies have addressed saliva proteome differences in early childhood dental caries [Al-Tarawneh et al, 2011;Martins et al, 2012]. To understand the possible relationship between salivary peptides and dental caries, further investigation of specific proteins is essential.…”

“…The mass spectra generated by this technique are easy to interpret [Al-Tarawneh et al, 2011], and this method has been used to analyze proteins in many diseases and disorders, including Sjögren's syndrome [Ryu et al, 2006] and breast cancer [Streckfus et al, 2006].…”

Progresses and Challenges of Omics Studies and Their Impacts in Personalized Medicine

“…In addition, most omics studies are cross-sectional in nature. We need to do more longitudinal studies and follow multiple targets in the same subject [5].…”