Biomarker discovery

Biomarker discovery
• Due to their multiple involvement in biological systems, peptides are
ideal biomarker candidates. According to the NIH definition,
"biomarker" has been defined as a characteristic that can be
measured and evaluated as an indicator of normal biologic processes,
pathologic processes or pharmacologic responses to therapeutic
intervention. Since peptides can migrate between compartments of
an organism, lots of pathogenic processes can be reflected by
characteristic, pathognomonic changes of the composition of
peptides in different body fluids. Peptide abundance changes
associated with various diseases have already been detected.

• Currently two peptidomic approaches for biomarker discovery are under
investigation: pattern recognition and mono-/oligo- biomarker detection. For
the former, there is no need to obtain identity information of biomarker
candidates, to designate patient samples with high specificity and sensitivity,
solely based on the MS pattern.
• Single/oligo biomarkers are more useful and reliable compared with the
pattern recognition, because peptide differences in expression levels can be
assigned and validated in biological samples collected from multiple sources.
Mass spectrometry has a great potential to enter clinical chemistry. This
analytical method is capable to reveal concentrations of analyte molecules
simultaneously with an extraordinary high specificity, given by the precise
macromolecular mass and sequencing capability.

• In order to screen and validate peptide biomarkers, therefore it needs
to fulfill two tasks in parallel: to identify the peptides present in a
sample (qualitative) and to determine corresponding concentrations
(quantitative). Only the combination of both will allow the selection
of peptide candidates. Usually this work is not restricted to a specific
type of analytical instruments, and lots of analytical techniques are
currently used for biomarker detection. But we believe the mass
spectrometry coupled to various liquid chromatography, such as UPLC
and nanoLC, can be taken as the optimal analytical platform with high
resolution, sensitivity, throughput and quantitation capabilities.