Serum Glucose-6-Phosphate Dehydrogenase Activity as a Biomarker for Gastric Cancer Stage Prediction

<b>Background</b>: Gastric cancer is the fifth most prevalent cancer diagnosed worldwide, and approximately 40% of patients who experience recurrence within five years develop hematogenous metastasis. Given that early prediction of recurrence may improve overall survival, there is a need for a biomarker that allows for repeated measurements and can accurately predict cancer stage. This study aimed to evaluate the potential of glucose-6-phosphate dehydrogenase activity, which is a factor associated with cancer progression, as a biomarker for predicting the stage of gastric cancer. <b>Methods</b>: This cross-sectional study retrospectively analyzed the medical records of patients with gastric cancer. Patients were classified into early-stage (Stage I-II) and advanced-stage (Stage III-IV) groups, and serum G6PD activity was compared between the two groups. Receiver operating characteristic (ROC) curve analysis was conducted to calculate the area under the curve (AUC), identifying the optimal cutoff value, and to determine the corresponding sensitivity and specificity. <b>Results</b>: Serum G6PD activity was significantly higher in the advanced-stage group compared to the early-stage group. Moreover, ROC curve analysis yielded an AUC of 0.70, indicating fair diagnostic performance. The optimal G6PD cutoff point was determined to be 12.05 U/g Hb, corresponding to a sensitivity of 0.59 and a specificity of 0.78. <b>Conclusions</b>: This study demonstrated the clinical utility of serum G6PD activity in predicting the stage of gastric cancer. As the test requires only a single drop of blood and provides rapid results, the test could be a practical tool for monitoring of recurrence in gastric cancer follow-up settings.