Variations in protein expression associated with oral cancer

BACKGROUND: Differential protein expression of the oral microbiome is related to human diseases, including cancer. OBJECTIVE: In order to reveal the potential relationship between oral bacterial protein expression in oral squamous cell carcinoma (OSCC), we designed this study. METHODS: We obtained samples of the same patient from cancer lesion and anatomically matched normal site. Then, we used the label free quantitative technique based on liquid chromatography tandem mass spectrometry (LC-MS/MS) to analyze the bacteria in the samples of oral squamous cell carcinoma at the protein level, so as to detect the functional proteins. RESULTS: Protein diversity in the cancer samples was significantly greater than in the normal samples. We identified a substantially higher number of the taxa than those detected in previous studies, demonstrating the presence of a remarkable number of proteins in the groups. In particular, proteins involved in energy production and conversion, proton transport, hydrogen transport and hydrogen ion transmembrane transport, ATP-binding cassette (ABC) transporter, PTS system, and L-serine dehydratase were enriched significantly in the experimental group. Moreover, some proteins associated with Actinomyces and Fusobacterium were highly associated with OSCC and provided a good diagnostic outcome. CONCLUSION: The present study revealed considerable changes in the expression of bacterial proteins in OSCC and enrich our understanding in this point.