CDK4 and triple-negative breast carcinoma: A preclinical study for the potential treatment of triple-negative breast cancer and its brain metastases showed that fluphenazine hydrochloride induces downregulation in the expression of cyclin-dependent kinases (CDK) 2, CDK4 and cyclin D1 and the up-regulation of P21 and P27, as well as intrinsic mitochondria-mediated apoptosis in vitro through the induction of G0/G1 cell cycle arrest [531].