CDKN1B and cancer: The assessment of p27kip1 expression seems very useful to select patients for more aggressive therapies and to establish which cases can benefit from cell cycle inhibitor suitable drugs candidates [56] (i.e. the epidermal growth factor receptor tyrosine kinase inhibitor ZD1839 [57] and the cyclin-dependent kinase modulator UCN-01 (7-hydroxy-staurosporine) [58] or from new cancer gene therapy [59,60].