CD8A and breast cancer: Among the 22 genes we identified, 15 (ACAP1, MAP4K1, CXCR3, TRAC, CD8A, CXCR6, TRBC2, TRAF1, CD3E, APOBEC3G, TRBV28, TRBV7-9, HLA-DPB1, CD6 and CST7) have previously been reported to be involved in the occurrence, development, malignant transformation and pathology of breast cancer, and to be associated with the survival and prognosis of patients [29–33].