The primary aim was to develop an initial study to prove how gastric cancer organoids are used to predict the tumor response of individual patients. The study tested the potential of organoids to predict tumor responses. The effect of standard care therapies on organoids was compared with the results of in vivo treatment. The cultures were treated with chemotherapeutic drugs corresponding to patient treatment. Gastric cancer is the 5th most common type and the 3rd foremost cause of cancer-related deaths, with a 5-year survival rate of less than 30%.  The incidence of gastric cancer is four times more common in Japan than in the United Kingdom and the United States and occurs at a younger age. Randomized data have established that surgery alone for gastric cancer treatment results in reduced survival and increased recurrence rates compared with multimodality therapy.

A current limitation for gastric cancer treatment is the lack of a reliable approach to identify which treatment options are most effective for each patient. For example, human epidermal growth factor receptor 2 (HER2) expression is used as a biomarker to predict response to anti-HER2 monoclonal antibody trastuzumab in patients with metastatic gastric cancer. HER2 expression is currently determined by immunohistochemistry or by the detection of HER2 gene amplification by fluorescence in situ hybridization. Due to tumor heterogeneity, these approaches may represent inaccuracies in HER2 testing. Hence, diverse approaches are required to improve the testing reliability to ensure that patients receive appropriate therapy for their disease.