Peripheral Blood Gene Expression and Protein Profiles of Purinergic and Glutamatergic Signaling Components and PD-L1...

Gastric cancer remains a major cause of cancer-related mortality worldwide, highlighting the need for an improved understanding of its molecular mechanisms. Purinergic and glutamatergic signaling pathways, immune checkpoint molecules, and oxidative stress are thought to contribute to tumor biology; however, their combined evaluation in gastric cancer is limited.

Gene expression levels of glutamate receptor ionotropic N-Methyl-D-aspartate 2A (GRIN2A), purinergic receptor P2X1 (P2RX1), and programmed death-ligand 1 (PD-L1/CD274) were analyzed using real-time PCR, while serum protein levels were determined by ELISA. Total antioxidant status (TAS) and total oxidant status (TOS) were also measured to assess systemic oxidative balance.

Gene expression analysis revealed an increased expression trend for P2RX1 in the gastric cancer group compared with healthy controls, whereas GRIN2A and CD274 (PD-L1) expression levels showed numerical decreases. Serum concentrations of GRIN2A and PD-L1, as well as TAS and TOS levels, were numerically higher in patients with gastric cancer; however, none of these differences reached statistical significance (p > 0.05). Likewise, serum P2RX1 levels did not differ significantly between groups. Receiver operating characteristic (ROC) analysis demonstrated area under the curve (AUC) values close to 0.5 for all evaluated parameters, indicating limited discriminatory and diagnostic performance.

These findings suggest that these molecular markers may reflect disease-related biological alterations rather than serve as independent circulating diagnostic biomarkers in gastric cancer.