Identification of over-expressed proteins in oral squamous cell carcinoma (OSCC) patients by clinical proteomic analysis

Background: Oral cancer is a worldwide problem. It is a universal aggressive disease in the population of smoking and drinking. The oral cancer mortality has been ranked 5th place in Taiwan in male cancer patients. A number of protein markers for oral cancer are still not applicable in large populations. Proteomic technologies provide excellent tools for rapid screening of a large number of potential biomarkers in malignant cells. Method: Proteomics and real-time quantitative RT-PCR were used to analyze over-expressed proteins in 10 OSCC patients. Result: Forty-one proteins were identified as commonly over-expressed in OSCC tissues. In OSCC tissues, αB-crystallin, tropomyosin 2, myosin light chain 1, heat shock protein 27 (HSP27), stratifin, thioredoxin-dependent peroxide reductase, flavin reductase, vimentin, rho GDP-dissociation inhibitor 2 (rho GDI-2), glutathione S-transferase Pi (GST-pi) and superoxide dismutase [Mn] (MnSOD) were significantly over-expressed (an average of 7.2, 6.0, 5.7, 4.3, 3.6, 3.4, 3.0, 3.0, 2.6, 2.5, 2.1-fold, respectively). In real-time quantitative RT-PCR analysis, the gene expressions of αB-crystallin, HSP27 and MnSOD were also increased in the cancer tissues, consistent with proteomic results. Conclusion: The identified proteins in this experiment may be used in future studies of carcinogenesis or as diagnostic markers and therapeutic targets for OSCC.