Small Molecules As Potential Biomarkers of Early Gastric Cancer: A Mass Spectrometry Imaging Approach.

BACKGROUND AND AIMS:Early detection of gastric cancer is an effective way to decrease the associated mortality. Efficient methods are needed to provide more sensitive biomarkers for detection of early gastric cancer (EGC).MATERIALS AND METHODS:We performed liquid extraction-electrosonic spray ionization mass spectrometry imaging and immunofluorescent staining of enzymes related to lipid synthesis on cancerous and paracancerous tissues obtained from six EGC patients and investigated the serum lipid profiles. Areas under the receiver operating characteristic curves were used to determine the diagnostic accuracy of putative biomarkers.RESULTS:Five lipids detected in the positive ion mode and seven in negative ion mode displayed higher relative intensities in the cancerous than the paracancerous tissues. Seven lipids detected in the positive ion mode and seven in the negative ion mode displayed lower relative intensities in the cancerous than the paracancerous regions. Phosphatidylcholine (34:3) and phosphatidylcholine (36:1) showed higher relative intensities in the cancerous than in the paracancerous tissues and showed higher relative intensities in the serum of EGC patients than healthy controls. Phosphatidylcholine (32:0) showed lower relative intensities in the cancerous than in the paracancerous tissues and lower relative intensities in the serum of EGC patients than healthy controls. The areas under the receiver operating characteristic curves of serum phosphatidylcholine (32:0) and phosphatidylcholine (34:3) for identifying EGC patients were 1.000 and 0.978, respectively.CONCLUSIONS:Regions associated with EGC showed different lipid distributions and enzyme expression from the paracancerous regions. Serum Phosphatidylcholine (32:0) and phosphatidylcholine (34:3) are potential biomarkers for discriminating between EGC patients and healthy controls.