PDCD1 and breast cancer: The reason for this is unclear; however, studies examining the synergistic effect of RFA’s abscopal effect and anti-PD-1 antibody in a mouse prostate cancer model [26] and carboplatin and anti-PD-1 antibody in a mouse breast cancer model [38] showed that anti-PD-1 antibody alone did not significantly increase the number of spots, which is consistent with the results of the present study in that no significant increase in the number of spots was observed with PD alone.