CDKN1A and breast cancer: The third family with an involvement in the regulation of AD [92] and PD [93] is miR-106b family promoting also cell-cycle progression and inducing G1-arrest through negative regulation of the cyclin-dependent kinase inhibitor 1A (p21/CDKN1A) [94]; moreover, in breast cancer cells this miRNA family is able to target breast cancer metastasis suppressor 1 (BRMS1) and RB1 [95].