PIK3R1 and prostate cancer: Additionally, a combination of four miRNAs (miR-19b, miR-23b, miR-26a, and miR-92a) was found to regulate PTEN expression post-transcriptionally and to affect the downstream PI3K/Akt pathway via PIK3CA (p110α), PIK3CD (p110δ), PIK3R1 (p85), Akt, and cyclin D1, thus promoting prostate cancer cells proliferation in vitro (98).