PRF1 and breast cancer: Similarly, gene expression analysis of immune-related genes showed distinguished expression patterns of multiple immune-related genes, such as TCRB, CD4, CD8, FOXP3, granzyme A (GZMA), perforin 1 (PRF1), HLA-A and HLA-DQA1, and the ratios of CD8/TCRB, GZMA/TCRB, PRF1/TCRB, FOXP3/TCRB and CD8/FOXP3 among three different portions in individual tumors (Figure 2C), further suggesting that the immune microenvironment is spatially heterogeneous in these five breast cancer cases.