The overexpression of RASIP1 caused a significant increase of G1/S checkpoint markers, cyclin E1 and D126, and a decrease of p27, an inhibitor of cyclin E-cyclin-dependent kinase (CDK) 2 and cyclin D-CDK4/626, accompanied with the reduced G1 phase distribution and elevated S phase distribution of DLBCL cells. The gene discussed is CDK4; the disease is diffuse large B-cell lymphoma.