**7. Conclusion**

Gastric cancer represents a major health problem worldwide, with most of the patients being diagnosed in advanced stages of the disease, associated with poor prognosis. Gastric tumors are molecularly heterogeneous; therefore, it is of major importance to identify the molecular subtype of the tumor and specific molecular biomarkers in order to assess the prognosis of the patient.

Furthermore, it is essential to identify molecular biomarkers that could predict treatment response according to the genetic and epigenetic profile of the patients and also to identify the occurrence of chemoresistance using specific markers, in order to obtain maximum response. The discovery of the molecular background of gastric cancer leads to the development of novel molecular targeted treatments. Heretofore, among the multitude of classes of agents targeting different signaling pathways, such as VEGF, EGFR, HER-2, IGF, immunotherapy, and mTOR pathways, only anti-HER2 monoclonal antibody trastuzumab and anti-VEGFR antibody ramucirumab have been approved for the treatment of advanced gastric cancer. Also, Apatinib, an anti-VEGFR2 TKI demonstrated efficiency in Chinese gastric cancer patients, receiving approval for treatment in this setting. Moreover, there are other classes of agents such as immunotherapy drugs (e.g., Pembrolizumab) that showed encouraging results in clinical trials, but we have still to wait for the final results until implementing them in clinical practice.

Therefore, further clinical studies are needed to demonstrate the effectiveness of molecular targeted treatments in order to have a personalized treatment approach and to improve the outcome of gastric cancer patients.
