Frőhlich formulated the hypothesis of coherent electrical polar oscillations in biological systems. The hypothesis predicts that generated electromagnetic field with a dominant electric component has a basic role in organization, transport, and interactions inside a cell and among cells. If mitochondria are entirely functional, the cellular cytoskeleton satisfies conditions for excitation of coherent states, which are assumed to be essential for normal biological activity. Malfunctioning mitochondria and disintegrated cytoskeleton result in disturbances of the Frőhlich's mechanism and consequently -- together with biochemical disturbances -- can lead to malignant properties of cancer cells.