Ito et al. (2018) reported that the mRNA levels of the IRGs PD-L1 and CD8 may reflect the antitumor immune response, with low PD-1 and high PD-L1 mRNA levels independently implicated as poor prognostic markers in gastric cancer patients who underwent surgery. Bai et al. (2019) reported the involvement of seven IRGs in the occurrence, development, malignant transformation, and pathology of breast cancer. This evidence concerns the gene CD8A and breast carcinoma.