A Cell Line Derived Xenograft (CDX) is a type of preclinical cancer model used in research to study the behavior of human cancer cells in vivo. CDX models are created by implanting human cancer cells that have been grown in a laboratory setting into immunodeficient mice or rats.

The cancer cells used for the CDX model are typically derived from a patient’s tumor and are maintained in vitro as a cell line. The cells are then injected into a mouse or rat, which provides an environment for the cells to grow and form a tumor.

CDX models are widely used in cancer research as they provide a relatively simple and efficient way to study the behavior of human cancer cells in vivo. They are particularly useful for testing the efficacy of new cancer therapies, as the model allows researchers to evaluate the effectiveness of a treatment on tumor growth and metastasis in a more physiologically relevant setting.

However, it is important to note that CDX models do have limitations. They do not fully recapitulate the complex microenvironment of a human tumor, and they do not account for the variability of individual patient tumors. Therefore, CDX models should be used in combination with other preclinical models and clinical studies to improve our understanding of cancer biology and develop more effective treatments.