New Approaches of proteomics in cancer and stem cells: Part I: from Basic Research to Clinical Application

Proteomic analysis based on the separation and identification of proteins/peptides is a powerful tool for discovering new biomarkers.Twodimensional differential gel electrophoresis (2D-DIGE), the ProteinChip array®, ClinProt®, and liquid chromatography are known as separation technologies.Although the detection and identification of proteins/peptides could be performed using mass spectrometry (MS), the types of MS used are diverse and the characteristics depend on the ionization method (e.g., matrix-assisted laser desorption/ionization [MALDI], surfaceenhanced laser desorption/ionization [SELDI], and electrospray ionization [ESI]) and mass analyzer (e.g., time-of-flight [TOF], quadrupole [Q], and ion trap [IT]).The diverse proteomic systems that couple separation technologies with MS have been successfully applied to search for cancer biomarkers in biological fluid such as serum.Until now, many cancer biomarkers have been reported to be identified from serum and plasma.In order to identify diagnostic biomarkers of hepatocellular carcinoma (HCC) and adult T-cell leukemia (ATL), which are both human viral malignancies, we have been analyzing sera from patients using the ProteinChip array®-SELDI system and MALDI-TOF-TOF-MS.In this review, we present an overview of proteomic technologies used to search for biomarkers and cancer biomarkers discovered by these technologies, including our data on HCC and ATL.Cancer diagnosis using these proteomic biomarkers is also described.