Abstract
An in vitro system for evaluating the safety of tissue-engineered products is a convenient because of its rapidity and low cost. On the basis of recent studies, intercellular channels called gap-junctions are considered to play an important role on the tumor-promotion stage during the tumorigenesis induced by polyurethanes. Further, we also demonstrate the significance of the intercellular communication during neuronal cell differentiation. From these results, we propose a survey of the function of the gap-junctional communication as a probable useful marker for evaluating the safety of tissue-engineered products.