Using NSG recipient mice improves engraftment of gastric cancer patient derived xenografts.

70Background: Previous gastric cancer (GC) patient derived xenograft (PDX) studies reported engraftment rates inversely proportional to the immunocompromised states of recipient mice (nudes 17%, scid 27%, and NOD/scid 34%). We tested highly immunocompromised NOD scidgamma (NSG) mice, which lack mature T cells, B cells, or functional natural killer cells, as recipients for low volume biopsies and post-treatment GC samples. Methods: Consent was obtained from GC patients who were scheduled to undergo esophagogastroduodenoscopy (EGD) and diagnostic laparoscopy as part of their disease management strategies. The following amounts of tumor were coated with Matrigel and inoculated into the flanks of NSG mice: EGD biopsies ~10 mg, post-treatment samples ~100 mm3, and peritoneal metastasis biopsies ~100 mm3. Tumors were serially measured and passaged when the greatest dimension reached 1.5 cm, or if there was overlying skin necrosis. Results: The engraftment rates were: EGD biopsies 48% (13 of 27 samples), post-re...