Loss of expression of miRs-205, −34b/c and −302a, which target Bcl2 and AKT, has been documented in high-grade prostate cancers [34–37], whereas, up-regulation of miRNAs including miRs-183, −153, and −125b, which target SMAD4, PTEN, p53, Puma and Bak1 has been noted in aggressive prostate cancers [38–40]. This evidence concerns the gene SMAD4 and prostate cancer.