Establishment of a Patient-derived Xenograft for Development of Personalized HER2-targeting Therapy in Gastric Cancer

To maximize success rate for development of HER2-targeted therapeutics, patient-derived xenograft (PDX) models reflecting HER2-positive gastric cancer (HER2 GC) patients were established. GC tissues obtained from surgery of GC patients were implanted into immune-deficient mice, and tumor tissue of HER2 PDXs were verified of the patient-mimic HER2 expression by immunohistochemistry and explored for the feasibility by testing with Herceptin, the approved therapeutics and novel HER2 antibody therapeutics being developed. We obtained 5 cases of HER2 GC PDX models reflecting patient's GC tumor, consisting of 2 cases of HER2 3+ and 2 cases of HER2 2+. Novel HER2 antibody displayed significantly improved anti-cancer efficacy in combination with Herceptin. The HER2 GC PDX models were successfully established to be utilized for preclinical evaluation of HER2-targeting drugs and combined therapies for GC treatment, as an ideal platform of personalized tools for precision therapy.