Chick Chorioallantoic Membrane or CAM Tumor Model: An In Ovo Method to Simulate Perineural Invasion of Tumor Cells

For grafting of a dorsal root ganglion onto the chorioallantoic membrane, use fine, sterile forceps to carefully grasp one ganglion in the culture dish and gently wash the tissue in a container of fresh HBSS. Place the ganglion onto the chorioallantoic membrane of one egg, being careful not to puncture the membrane, and cover all of the egg openings with sterile transparent film dressings. When all of the eggs have been grafted, return them to the humidifying egg incubator for 2 days without rotation.

At the end of the incubation, transfer the eggs to the laminar flow cabinet, and use scissors and forceps to open the transparent film dressing. Next, add 0.5 to 1 million fluorescently labeled tumor cells in 5 microliters of HBSS onto the chorioallantoic membrane of each egg, about 2 millimeters from each dorsal root ganglion, keeping a uniform distance between the ganglia and the cells. Then, cover the eggs with a new film dressing and return the eggs to the egg incubator for 7 days without rotation.