Proteins Biomarkers for Diagnosing Gastric Cancers: Perspectives Through Mass Spectrometry-Based Discoveries

Gastric cancer is a significant cancer threat globally. The disease heterogeneity at both genetic/ epigenetic and proteomic levels poses difficulties in mining for relevant clinical biomarkers. Genetic markers are not only used extensively in clinical practice but are also primarily confined to specific genetic cohorts. In the recent decade, mass spectrometry-based proteomics methods have enabled the discovery of numerous biomarkers for GC. A diagnostic assay using protein signatures has advantages over genetic markers as the former lies proximal to the phenotype. Genetic markers can also be probed at the protein level using modified peptide sequences. In addition to genetic markers at the protein level, mass spectrometry can also be used to develop assays with a panel of posttranslational modifications and neoantigens. The biomedical community must expedite the path from discovering many diverse types of protein biomarkers to their clinical utility in the years to come. In this context, we discussed the discovery and validation of potential protein biomarkers for diagnosing gastric cancers and the bottlenecks in developing diagnostics for clinical implementation in this chapter.