The four miRNAs regulate PTEN expression post-transcriptionally, and affect the downstream PI3K/Akt pathway via PIK3CA (p110α), PIK3CD (p110δ), PIK3R1 (p85), Akt as well as cyclin D1, thus promote prostate cancer cell proliferation in vitro. This evidence concerns the gene PIK3R1 and Familial prostate cancer.