ART1 is a cell - surface protein. It belongs to the ADP - ribosyltransferase family and plays diverse roles in multiple cellular activities. In the immune system, CD296 is involved in T - cell activation and immune regulation, thereby influencing the intensity and direction of immune responses. For example, it may modulate the signaling pathways that determine whether T - cells proliferate, differentiate, or become activated to combat pathogens. In cancer research, abnormal expression of CD296 has been detected in some tumor cells. This aberrant expression is potentially linked to critical tumor - related processes such as cell proliferation, migration, and immune escape.