The proliferation capacity of normal and transformed cells largely depends on extracellular signals, such as growth factors and the interaction between adhesion receptors and the extracellular matrix [1, 2]. At the same time, it is conceivable that the degree of cell attachment to the extracellular matrix depends on the cell cycle stage. To test whether this dependence actually existed, we analyzed the characteristics of the attachment and flattening of cells at different stages of the cell cycle. If nontransformed cells remain in suspension for a long time, they are arrested in the late G1 phase of their division and undergo apoptosis [3, 4]. The behavior of transformed cells may differ from that of normal cells. Studies aimed at determining the stages at which these cells are less capable of attaching may help to understand the relationship between the division stage and the metastasizing potential of tumor cells.