The results of our present study confirm the earlier interesting observation showing that treatment of cancer cells with microtubule inhibitors such as vinblastine, colchicine and paclitaxel, causes a strong up-regulation of cyclin B1 and Cdc2 protein levels [9]–[12], while the level of Cdc2 phosphorylation at Tyr15 (an inactive form of Cdc2) was not significantly changed [23]. This evidence concerns the gene CDK1 and cancer.