CDKN1B and breast cancer: Vincent et al. found that expression of Nuclear Protein 1 (NUPR1), a transcriptional regulator of p21WAF1/KIP1 expression, mediates growth benefit and chemoresistance by causing Akt-mediated phosphorylation, subsequent cytoplasmic relocalization of p21WAF1/KIP1 and activation of the anti-apoptotic Bcl-xL protein in breast cancer cells [58].