IFNG and Familial prostate cancer: To assess whether primary tumors can also induce IFNG signaling in the premetastatic niche, we examined scRNA-Seq data of peripheral zone tissues from prostatectomies obtained from men with histologically confirmed prostate cancer (18 samples from 10 men) (5), referred to here as “primary tumor.” Differential gene expression analysis verified that T cells of primary tumors significantly expressed IFNG (log2FC = 7.1, adj P < 1 × 10–100, Supplemental Figure 3A).