PDCD1 and glioblastoma: Similarly, while photodynamic therapy has been shown to positively interact with PD-1 or PD-L1 blockers in various syngeneic mouse models of mammary carcinoma [60, 61] and CRC [60], low-dose pulsed ultrasound has been reported to synergize with a monoclonal antibody specific for PD-1 and doxorubicin in immunocompetent mice bearing orthotopic CT2A or GL261 glioblastomas [62].