PRF1 and breast cancer: Moreover, a strong intra-tumoral infiltrate of cytotoxic CD8+ T lymphocytes was found to be significantly associated with improved overall survival in BC, independent of standard prognostic and predictive factors such as age at diagnosis, histological grade, ER, PR and HER-2 status, among others.48 In addition, Alcaraz-Sanabria et al.49 demonstrated that a gene signature including IFNG, CXCL13, and PRF1 correlate with better overall survival and with a higher level of tumor immune infiltrates (B cells, CD4+ and CD8+ T cells, DCs) in basal-like BC.