Serum Proteome Analysis for Early Detection of Cancer
Proteome analysis has been used for the identification of biomarkers or biomarker patterns that may allow for the early diagnosis of cancer. This tool is of special interest, since it allows for the identification of tumor-derived secretory products in serum or other body fluids. In addition, it may be used to detect reduced levels or loss of proteins in the serum of cancer patients that are present in noncancer individuals. These changes in the serum proteome may result from cancer-specific metabolic or immunological alterations, which are, at least partly, independent of tumor size or mass, thereby fascilitating early discovery.
Synthetic Biomarker-Based POC Diagnostic for Cancer
There is a need for low-cost, noninvasive methods to diagnose and treat cancer, especially in resource-limited developing countries. Molecular biomarkers combined with low-cost POC assays are a potential solution for diagnosing cancer. Synthetic biomarker technology can amplify signals from tumor proteins that would be hard to detect on their own. These proteins, matrix metalloproteinases, help cancer cells escape their original locations by cutting through proteins of the extracellular matrix, which normally holds cells in place. These synthetic biomarkers are composed of nanoparticles conjugated to ligand-encoded reporters via protease- sensitive peptide substrates (Warren et al. 2014). Upon delivery, the nanoparticles passively target solid tumors where up-regulated proteases cleave the peptide substrates and release reporters that are excreted into urine. The reporters are engineered for detection by sandwich immunoassays, and can be quantified directly from unmodified urine; furthermore, capture antibody specificity enable the probes to be multiplexed in vivo and quantified simultaneously by ELISA or paper lateral flow assay. Synthetic biomarkers, specific for colorectal cancer, were designed and urinary detection of these was demonstrated in mouse models by paper diagnostic, which works much like a pregnancy test. This approach can be applied universally without expensive equipment or trained personnel.