Multiple reaction monitoring (MRM/SRM) of peptides is a growing technology for target protein quantification because it is more robust, precise, accurate, high-throughput, and multiplex-capable than antibody-based techniques such as enzyme-linked immunosorbent assays (ELISAs). The technique has been applied clinically to the large-scale quantification of multiple target proteins in different types of fluids. However, previous MRM-based studies have placed less focus on sample-preparation workflow and analytical performance in the precise quantification of proteins in saliva, a non-invasively sampled body fluid.
Oral cancer is a type of head and neck cancer where the cancerous tissue is in the oral cavity. Saliva has been found to contain more than 1000 proteins, mRNAs, microRNAs, and metabolites that span a wide range of biological functions. Abnormalities found in the cancerous tissue can be detected in the saliva, which provides an alternate non-invasive detection of oral diseases. Previous studies have profiled the saliva proteome to discover disease biomarkers, including those for cancer.
In a new study published in Molecular and Cellular Proteomics, Professor Yi-Ting Chen and a team of scientists from the Department of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan Taiwan, evaluated the analytical performance of a simple and robust MRM-based targeted proteomics approach incorporating liquid chromatography with mass spectrometry detection (LC-MRM/MS). The platform was used to quantitatively assess the biomarker potential of a group of 56 salivary proteins that have previously been associated with human cancers.
To further enhance the development of this technology for assay of salivary samples, Professor Chen’s team optimized the workflow for salivary protein digestion and evaluated quantification performance, robustness and technical limitations in analysing clinical samples. Using a clinically well-characterized cohort of two independent clinical sample sets (total n = 119), they quantitatively characterized these protein biomarker candidates in saliva specimens from controls and oral squamous cell carcinoma (OSCC) patients.
The results showed a significant elevation of most targeted proteins in saliva samples from OSCC patients compared with controls. Overall, this platform was capable of assaying the most highly multiplexed panel of salivary protein biomarkers, highlighting the clinical utility of MRM in oral cancer biomarker research.
For the full journal article see the reference below:
Chen, Y.-T., Chen, H.-W., Wu, C.-F., Chu, L. J., Chiang, W.-F., Yu, J.-S., … Ou Yang, W.-T. (2017). Development of a multiplexed LC-MRM/MS method for evaluation of salivary proteins as oral cancer biomarkers. Molecular & Cellular Proteomics. doi:10.1074/mcp.m116.064758