**Clinical Implications of Molecular Heterogeneity of Gastric Cancer**

Petra Hudler and Radovan Komel

Additional information is available at the end of the chapter

http://dx.doi.org/10.5772/intechopen.69775

#### **Abstract**

Gastric cancer incidence has been steadily declining in countries with low frequencies of gastric carcinoma since early 1930s. In areas with higher incidences, the decline has been less obvious and slower. Nevertheless, gastric adenocarcinoma remains one of the most common causes of cancer‐related death worldwide. The poor outcome has been attributed to late detection of the condition, particularly in Americas and Europe, aggressive patho‐ genesis and lack of symptoms during early stages of the tumor development. In addition, sporadic stomach cancer mostly affects elderly individuals. In the majority of countries with low incidence, the average age at the disease presentation is above 65. Therefore, gas‐ tric adenocarcinoma, among other diseases associated with old age, raises health concerns in countries with changing demographic age profiles that show a trend of an increase in the proportion of the population aged over 60. The low 5‐year survival rate of patients underscores the critical need for the development of more accurate diagnostic tools and safe targeted chemotherapeutics. However, the heterogeneity of molecular changes rep‐ resents one of the most pressing issues in the current research of gastric cancer, impeding the translation of genetic aberrations into novel applications for medical practice.

**Keywords:** antineoplastic agent, cancer, chemotherapy, clinical trials, gastric adenocarcinoma, gastroesophageal junction adenocarcinoma, molecular heterogeneity, monoclonal antibodies, small‐molecule inhibitor, targeted therapy
