IL15 and prostate cancer: Interestingly, a number of the 51 genes higher in AI prostate and ER- breast were previously associated with the immune response, including ELF4, GBP1, CXCL2, IL6, IL7R, and IL15. IL6 (interleukin 6) in particular – indicated here to be a transcriptional target of the EGFR pathway (Figure 4) – has been shown to promote prostate tumor growth and to play a role in the interaction between epithelial and stromal cells in prostate cancer [40].