Establishment of Orthotopic Xuanwei Lung Cancer SCID Mouse Model 
and Analysis of Biological Properties

Background and objective The incidence of Xuanwei lung cancer ranks first in China, and its pathogenesis requires in-depth investigation. This study aims to establish an orthotopic Xuanwei lung cancer severe combined immunodeficiency (SCID) mouse model and to provide a basic experimental platform for further study. Methods The Xuanwei lung cancer cell line XWLC-05 was inoculated into the lung tissue of SCID mice in high and low doses. The tumor formation rates, tumor characteristics, spontaneous metastases, and survival times of the mice were observed, taking a subcutaneously transplanted tumor as control. Results The tumor formation rates of the orthotopic transplantation of lung cancer cells in high and low doses were 81% and 83%, respectively, among which mice in the high-dose group appeared cachectic on day 13. Extensive invasion and adhesion were observed in the contralateral lung and thoracic cavity, but no distant metastasis was exhibited. Mice with low-dose cells in the orthotopic transplantation group appeared cachectic and distant metastasis occurred on day 25. The tumor formation rates in the subcutaneous inoculation group by the high and low doses of cells were 100% and 94.5%, respectively, and no distant metastasis was observed. The rate of metastasis within the orthotopic transplantation group and between the orthotopic and subcutaneous inoculation groups showed a significant difference (P<0.05). A significant difference was indicated by the survival rate within and between the groups (P<0.001). Conclusion We successfully established an orthotopic XWLC SCID mouse model, which lays the foundation for a more in-depth study