ABSTRACT
Altered intercellular communication Gap junctions are composed of intercellular channels between neighbouring cells, through which the exchange of inorganic ions or small molecules can be achieved. Intercellular communication is widely believed to be important for the maintenance of tissue homeostasis and differentiation because both positive and negative growthregulatory signals have been shown to pass gap junctions. Many neoplastic cells exhibit reduced or no intercellular exchange. Several in vitro studies utilizing isolated hepatocytes or other cells revealed that tumour promoters when added to the culture medium inhibit the intercellular transfer of test molecules. Therefore the hypothesis has been advanced that the inhibition of intercellular exchange may release cells from restrictions by the transmission of regulatory factors, thereby promoting the growth of preneoplastic cells (Klaunig and Ruch, 1990).
