It is notable that the PDCD1 (the PD-1 gene) or CD274 (the PD-L1 gene) expression levels were not different between PAGES-HBC Group 1 and Group 2 in the HER2+ breast cancer TCGA cohort (PDCD1, p = 0.193; CD274, p = 0.637);which indicated that PAGES-HBC might serve as a better prognostic marker representing the PD-1 positive immune environment related to therapy response and patient survival in HER2+ breast cancer. This evidence concerns the gene PDCD1 and breast cancer.