To set up a mouse dissemination model, use polystyrene foam to make a stopper, and disinfect it with 70% ethanol. Attach the needle to the stopper with the tip extending 5 millimeters out of the stopper. Bend the tip of a 30-gauge needle with clean forceps or against a hard object cleaned with 70% ethanol, and fill a syringe with 1 x 106 target tumor cells in 100 microliters of PBS.
Confirm a lack of response to pedal reflex in an anesthetized 19- to 21-gram 8- to 12-week-old female homozygote athymic nude mouse. Insert the needle into the chest through the intercostal space, moving the needle up and down to avoid contacting the ribs. When the tip has passed through the intercostal space, position the syringe so that it is pressed against the mouse and eject the entire volume of target cells. After the injection, roll the mouse 2 to 3 times to spread the cells throughout the thoracic cavity and return the mouse to its cage with monitoring until full recovery.
