A study by Tian et al. (2013) demonstrated in 2013 that miR-19b, miR-23b, miR-26a, and miR-92a may promote the proliferation of prostate cancer cells by synergistically regulating the expression of phosphatase and tensin homology, phosphoinositol 3-kinase/Akt, and CCND1 in vitro. This evidence concerns the gene CCND1 and Familial prostate cancer.