PRF1 and metastasis: The released granzymes and perforin were measured 6 h after the second radiation dose, coinciding with the observed immunological synapse formation in each treatment group receiving non-particlized or particlized tebentafusp with a second irradiation of 10 or 20 Gy in both the primary tumor and pulmonary metastasis (Fig. 6A: granzymes in primary tumor, B: granzymes in pulmonary metastasis, C: perforin in primary tumor, and D: perforin in pulmonary metastasis).