 Abstract cellular fusion between cancer cells and normal cells is a complex process involving multiple steps. First, the cells must be induced into a profusogenic state which involves changes in their cytoskeletons and plasma membranes. Additionally, certain proteins and lipids must be expressed to facilitate fusion. Once fusion has occurred, the cells undergo a selection process to determine whether they will remain fused or not. This process can also involve the formation of new cancer hybrids from normal cells. Finally, these hybrid cells may exhibit increased tumorogenicity and metastasis due to their enhanced plasticity. This article was authored by Thomas Ditmore and Ralph Hasse.