PRF1 and neoplasm: The extracellular antigen-binding domain of the CAR molecule specifically recognizes the tumor antigen; the intracellular domain of the CAR molecule recognizes signal transduction; and the intracellular domain activates the T cells, causing cells to proliferate, synthesize perforin and granzyme, release cytokines, and other processes that lead to tumor cell necrosis [25,26].