Development of simultaneous analysis of tryptophan metabolites in serum and gastric juice – an investigation towards establishing a biomarker test for gastric cancer diagnosis |
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| Authors: | Jong Min Choi Won Sang Park Kyo Young Song Hwa Jeong Lee Byung Hwa Jung |
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| Affiliation: | 1. Molecular Recognition Research Center, Korea Institute of Science and Technology, Seoul, Republic of Korea;2. Graduate School of Pharmaceutical Sciences, Ewha Womans University, Seoul, Republic of Korea;3. Department of Pathology, College of Medicine, The Catholic University of Korea, Seoul, South Korea;4. Department of Surgery, College of Medicine, The Catholic University of Korea, Seoul, South Korea;5. Department of Biological Chemistry, Korea University of Science and Technology, Daejeon, Republic of Korea |
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| Abstract: | To evaluate changes in tryptophan metabolism and discover diagnostic biomarkers for gastric cancer, a quantitative method was developed for tryptophan and its seven metabolites (indole‐3‐lactic acid, anthranilic acid, serotonin, nicotinic acid, kynurenic acid, kynurenine and 3‐indoxyl sulfate) in both human serum and gastric juice using liquid chromatography–tandem mass spectrometry (LC–MS/MS). Serum and gastric juice were prepared with a simple protein precipitation using aqueous 0.1% formic acid and acetonitrile. As a result, it was found that the kynurenine pathway of tryptophan metabolism was activated in gastric cancer and that the metabolic ratio of kynurenine/tryptophan, which reflects the enzyme activity of indoleamine‐2,3‐dioxygenase, was associated with the observed metabolic changes. Finally, the investigation of tryptophan metabolites, especially kynurenic acid, in serum and gastric juice might serve as biomarkers for gastric cancer. The findings in this study provide critical information of tryptophan metabolism which can be applied to a serum‐based diagnostic test for gastric cancer. |
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| Keywords: | gastric cancer gastric juice liquid chromatography– tandem mass spectrometry metabolite serum tryptophan |
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