SIRPA and cancer: Based on their immune-activating mechanisms, ACPs can be categorized into two main groups: targeted peptides that inhibit immune-related signal pathways aberrant in cancer cells such as PD-1/PD-L1 interaction, cGAS-STING pathway, and CD47/SIRPα; and lytic peptides, which form pores in cancer cell membranes to induce cell necrosis or apoptosis, and the cell fragments can act as tumor antigens to trigger the immune response.