IGSF8 and Familial prostate cancer: After identifying EGFR as the target of exosomal miR‐3934‐5p and clarifying the regulating role of EWI‐2 on the sorting and enrichment of miR‐3934‐5p into the exosomes, we then analyzed the functional roles of EWI‐2 in the regulation of prostate cancer cell signal transduction.