Dendritic cells are the pacesetters of the human immune system-they regulate the activity of immune cells in lymph nodes. Researchers at the University of Pittsburg Medical Center (UPMC) are "training" dendritic cells to target specific tumors afflicting individual patients. The researchers are able to do that by synthetic peptides that mimic a protein from a patient's tumor. When the altered dendritic cells are then injected into the patient, they activate the T-cells and other disease fighters to attack tumor cells throughout the body.