Cell-cell interaction and carcinogenesis.

Before carcinogenic stimuli are introduced, a potentially cancerous cell functions normally; growth is controlled and the cell exists in complete harmony with that of surrounding cells in a given tissue. During the process of multi-stage carcinogenesis, such harmony is destroyed and a presumptive initiated cell accomplishes a clonal expansion, neglecting the growth pattern of surrounding normal cells. Recent results from our own laboratory and others strongly suggest that blocked gap-junctional intercellular communication is an important determinant during the process of tumor promotion.