Upregulation of plasma C9 protein in gastric cancer patients |
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| Authors: | Poh‐Kuan Chong Huiyin Lee Marie Chiew Shia Loh Lee‐Yee Choong Qingsong Lin Jimmy Bok Yan So Khong Hee Lim Ross Andrew Soo Wei Peng Yong Siew Pang Chan Duane T Smoot Hassan Ashktorab Khay Guan Yeoh Yoon Pin Lim |
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| Institution: | 1. Cancer Science Institute of Singapore, Singapore, Singapore;2. These authors have contributed equally to this work.;3. Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore, Singapore;4. Department of Surgery, National University Hospital, Singapore, Singapore;5. Department of Surgery, Tan Tock Seng Hospital, Singapore, Singapore;6. Department of Hematology/Oncology, National University Hospital, Singapore, Singapore;7. Singapore Institute of Management University, Singapore, Singapore;8. Department of Medicine and Cancer Center, Howard University, Washington, DC, USA;9. Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore;10. Bioinformatics Institute, Agency for Science, Technology and Research, Singapore, Singapore |
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| Abstract: | Gastric cancer is one of the leading causes of cancer‐related deaths worldwide. Current biomarkers used in the clinic do not have sufficient sensitivity for gastric cancer detection. To discover new and better biomarkers, protein profiling on plasma samples from 25 normal, 15 early‐stage and 21 late‐stage cancer was performed using an iTRAQ‐LC‐MS/MS approach. The level of C9 protein was found to be significantly higher in gastric cancer compared with normal subjects. Immunoblotting data revealed a congruent trend with iTRAQ results. The discriminatory power of C9 between normal and cancer states was not due to inter‐patient variations and was independent from gastritis and Helicobacter pylori status of the patients. C9 overexpression could also be detected in a panel of gastric cancer cell lines and their conditioned media compared with normal cells, implying that higher C9 levels in plasma of cancer patients could be attributed to the presence of gastric tumor. A subsequent blind test study on a total of 119 plasma samples showed that the sensitivity of C9 could be as high as 90% at a specificity of 74%. Hence, C9 is a potentially useful biomarker for gastric cancer detection. |
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| Keywords: | Biomarker Biomedicine C9 Gastric cancer Plasma |
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