Abstract: Objective To establish subcutaneous and orthotopic transplant mice models by using human colon cancer clinic sample, in order to provide a useful tool for studying the characteristics of colon cancer and preventing and curing the colon cancer. Method Fresh colon cancer sample was transplanted subcutaneously into BNX mice and nude mice, then the tumor xenografts were maintained by serial passages in BNX mice and nude mice in order to establish subcutaneous transplantable tumor animal model, tumor size was monitored regularly every week. The tumor tissues were collected and orthotopically implanted into the cecum sub-serosa. The rates of tumor formation and metastasis were observed after animal sacrifice. The expression of ESA、CEA、C-erbB-2、P53 proteins were detected by immunohistochemistry. DNA aneuploid and cell cycle distributions of tumor cells were estimated by flow cytometry. Result The subcutaneous transplant model of colon cancer was established, the tumor formation rate of orthotopic transplant model was 62.5% without metastasis. Biopsy observation indicated that the xenograft tumor was pathologic stage II adenocarcinoma as same as the original human carcinoma. The expressions of ESA and CEA were strongly positive, C-erbB-2 and P53 were positive by immunohistochemistry. Flow cytometry was used to detect the change of cell cycle, the results indicated that the ratio in G₀ and G₁-phase was 67.50%±5.59%, 4.47%±2.31% in G₂ and M-phase and 28.02%±7.13% in S phase. DNA heteroploid detection showed that the heteroploid ratio of xenograft tumor was 1.74±0.02. Conclusion The subcutaneous and orthotopic transplant colon cancer model in mice was successfully established, which had the same biological characteristic as original human colon cancer.

Key words: Colon cancer, Tumor animal model, Subcutaneous transplantation, Orthotopic transplantation, Immunohistochemistry