Abstract: Objective To establish a patient derived xenograft (PDX) model of tumor tissue from patients with colorectal cancer (CRC) and to identify the factors affecting the tumorigenesis rate of PDX model, as well as to conduct a preliminary chemotherapy. Methods From November 2019 to October 2020, CRC patients undergoing elective surgery in Shaoxing People's Hospital were selected. The tumor tissue obtained from surgical operation was inoculated to the right lumbar back of NSG mice to establish a PDX model, which was subcultured to F3 generation, and the influencing factors of the tumor formation rate of PDX model were analyzed. Chemotherapy drugs include 5-fluorouracil, oxaliplatin and anesthetic propofol. Results A total of 60 patients with CRC were included in this study and 37 samples from patients had PDX tumor formation in mice with a tumorigenesis rate of 62%; The average tumorigenesis time was (34±12)d; Primary tumor malignant degree (tumor stage and degree of cell differentiation), preoperative carcinoembryonic antigen (CEA) level and tumor location of CRC patients affected the tumorigenesis rate of PDX model (P＜0.01). The biology of CRC-PDX transplanted tumor tissue was highly consistent with that of the patient's tumor tissue. All four chemotherapy regimens could inhibit tumor growth and cause tumor tissue damage. Propofol could inhibit diarrhea in mice and protect intestinal mucosa. Conclusions The CRC-PDX model established in this study may better keep biological characteristics of primary tumors and be used as a reference model for individualized treatment of CRC patients. The malignant degree of the primary tumor is the main factor affecting the tumorigenesis rate of PDX model.

Key words: colorectal cancer, patient derived xenograft, influencing factors, tumorigenesis rate, individualized treatment