Oral Cancer Plasma Tumor Marker Identified with Bead-Based Affinity-Fractionated Proteomic Technology

Abstract

Background: There is no plasma marker for detecting oral cancer, one of the most frequent cancers worldwide. We developed a bead-based affinity-fractionated proteomic method to discover a novel plasma marker for oral cancer. Methods: Affinity purification of heparinized plasma with magnetic beads and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) analysis were used to screen potential oral cancer markers. We compiled MS protein profiles for 57 patients with oral cancer and compared them with profiles from 29 healthy controls. The spectra were analyzed statistically using flexAnalysis TM and ClinProt TM bioinformatic software. In each MS analysis, the peak intensities of interest were normalized with an internal standard (adrenocorticotropic hormone 18 -39). For identification, affinity bead-purified plasma protein was subjected to MALDI TOF/TOF analysis followed by Mascot identification of the peptide sequences and a search of the National Center for Biotechnology Information protein database. Results: To optimize MALDI-TOF analysis based on the best discriminator of the cancer and control spectra, copper-chelated beads were used for plasma protein profiling. The within-and between-run CVs for assays were <4% and 7%, respectively. Six markers that differentiated between cancer and control spectra were found,

Enhanced Interferon Signaling Pathway in Oral Cancer Revealed by Quantitative Proteome Analysis of Microdissected Specimens Using 16O/18O Labeling and Integrated Two-dimensional LC-ESI-MALDI Tandem MS

“…Recently state-of-the-art proteomics technologies have revealed alterations in protein abundance, posttranslational modification and turnover, and spatial and temporal distribution within tumor specimens. Using proteomics approaches, aberrantly expressed proteins have been identified in body fluids (12)(13)(14), frozen or paraffin-embedded tissues (15)(16)(17)(18), and cultured cell lines (19 -22). The fold changes in protein expression in samples from healthy and cancerous states as well as the roles of each protein in disease progression must be determined to identify potential candidates for biomarkers and therapeutic targets.…”

Head and neck cancer

“…Cheng et al observed the high specificity and sensitivity of the fibrinogen a-chain fragment in oral cancer plasma, suggesting that it may be a clinically useful tumor marker. 45 In this study, the fibrinogen fragment presented higher sensitivity (100%) and specificity (97%) for cancer than the other markers detected, by MALDI ToF/ToF followed by Mascot identification. Previous studies in animal models have shown that inhibition of fibrinogen strongly diminishes the development of metastatic lung cancer, further demonstrating the important role of fibrinogen in sustaining invasion and survival of tumor cells.…”

“…Chemical chromatographic surfaces selectively purify certain subsets of proteins, allowing unbound impurities to be removed by washing with buffers. Proteins are typically enzymatically digested after elution and before matrix-assisted laser desorption/ ionization (MALDI) time of flight (ToF) MS analysis, among other forms of MS. 45 MALDI-ToF MS sensitively and precisely separates target proteins according to their mass-dependent velocities (m/z). Surface enhanced laser desorption/ionization (SELDI) ToF MS uses chip-based protein sample arrays with different chemical chromatographic surfaces to selectively bind proteins with specific chemical properties, such as hydrophobic, cationic-anionic, or metal-binding molecules, whereas nonspecifically bound proteins or impurities are removed by washing with buffers.…”

Comparative Serum Proteomic Analysis of Serum Diagnosis Proteins of Colorectal Cancer Based on Magnetic Bead Separation and MALDI-TOF Mass Spectrometry

“…Various proteomic approaches have been applied to biomarker discovery using biological fluids. It is being interestingly recognized that low mass weight peptides, such as S100A8 and fibrinogen, play an important role in physiological and pathological process and could be used as relevant biomarker candidates (Cheng et al, 2005;Tolson et al, 2006). Recently mass spectrum that directly detects and differentiates short peptides has offered a promising approach for peptidomic biomarker discovery (Alagaratnam et al, 2008;Chinello et al, 2010;Dai et al, 2010;Du et al, 2010;Liu et al, 2010).…”