Model-based numerical predictions of the dielectrophoretic behavior of spheroidal biological cells are carried out. Membrane electroporation has been specifically included to gauge its effect on the Clausius-Mossotti factor. It is shown that poration could be utilized as an additional flexible tool for cell separation. Furthermore, the simulation study focuses on differences in dielectrophoretic characteristics between normal and malignant cells, and that one cell type can be more prone to poration than another. These results point to the possibility of judiciously selecting electrical parameters for effective cell separation or tumor detection, especially in high conductivity media.