**6. The role of molecular biomarkers in the treatment of gastric cancer**

Besides the few standard chemotherapeutic agents having efficiency in the treatment of gastric cancer, molecular targeted therapy for gastric cancer is limited, including mainly agents acting on the HER2 and vascular endothelial growth factor (VEGF) pathways [71].

On the other hand, until present, the only used markers for gastric cancer in clinical practice are carcinoembryonic antigens, CA 19-9 [72] and CA-72 [73], with questionable efficacy. Nowadays, there are multiple molecular biomarkers that had shown their accuracy as diagnostic or prognostic tools but still need further validation for implementing in the routine clinical practice, predicting the response to chemotherapy, posttreatment survival, or disease recurrence.
