Figure 1.

Schematic diagram of surgical orthotopic implantation (SOI) for the colon cancer liver-metastasis model. After the patient’s liver-metastasis surgery, intact liver metastasis tumor tissue from the patient was initially implanted subcutaneously into nude mice to establish a stable patient-derived xenograft (PDX) model, defined as P0. After the P0 tumor grew to approximately 1 cm in diameter, the mice were sacrificed and the subcutaneous tumors were harvested, viable tumor tissue was minced into 2 mm³ fragments for orthotopic transplantation into the liver of the nude mice to establish a patient-derived orthotopic xenograft (PDOX) model. Please see materials and methods for details.