Consequently, CD8+ T-cell effector (Teff) score, comprising gene expression of IFNG, PRF1, CD8A and CD8B, and BATF3-DC score, calculated with the expression level of BATF3, IRF8, THBD, CLEC9A, and XCR118 were markedly increased in the high SLAMF6 group than in the low SL AMF6 group in breast cancer. The gene discussed is CD8B; the disease is breast cancer.