[26] performed iTRAQ labeling and LC-ESI-MS/MS to evaluate a discovery group of four GC samples and four adjacent healthy tissues, and found an AUC value of 0.734 for GLS1 and GGCT co-expression, suggesting that the level of co-expression had a high clinical value as a diagnostic biomarker for early GC. This evidence concerns the gene GGCT and gastric cancer.