Mass Spectrometry in Clinical Diagnosis: A Preliminary Application in Tumor Cellular Proteomics for Biomarker Discovery

Cancer is a group of diseases characterized by uncontrolled growth and spread of abnormal cells, which cause high mortality rates. The purpose of this study is to characterize the proteins secreted from the HepG2, MCF-7 and HT-29 cells, which may relate to cell differentiation and tumor metastasis. In the proteomic analysis, the secretome proteins were identified by reverse phase nano-high performance liquid chromatography/electrospray ionization tandem mass spectrometry (RP-nano-UPLC-ESI-MS/MS) followed by peptide fragmentation pattern analysis. Moreover, identifications of tumor cell protein expressions by proteomic approaches were indicated that several proteins may activate or enhance the PI3K/AKT/mTOR pathway. The PI3K/AKT/mTOR pathway has been shown to be related to the cancer cell metastasis and proliferation, and the ubiquitin C (UBC) may serve as potential protein diagnostic biomarker to be examined in further investigations.