CDKN1B and cancer: These results are in agreement with previous studies on the role of cyclin E and other cell cycle regulatory proteins (i.e. the CDK inhibitor p27Kip1) in determining the response of cells to cytotoxic agents and warrant further studies in this interesting area of cancer research (Croix et al, 1996; Smith and Seo, 2000; Yang et al, 2000).