CDKN1A and breast cancer: Prevention of this phosphorylation through expression of a phospho-null threonine to valine (Thr25Val) mutation in human breast cancer cells blocked the stimulation of the proteasomes by DYRK2, thus slowing the degradation of essential cell cycle regulatory factors like cyclin-dependent kinase inhibitor 1B (p27Kip1) and cyclin-dependent kinase inhibitor 1 (p21Cip1) (Guo et al., 2016).