CDK4 and breast cancer: Additionally, when MDA-MB-231 and MDA-MB-468 BC cells were infected with rMeV-Hu191 at MOIs of 0.1, 0.5, 1, 2, and 5 for 24 h, the expression levels of CDK4 and cyclin D1 decreased in an MOI-dependent manner (Fig. 3C).