GJA1 and cancer: Furthermore, the junctional stabilization of Cx43 and modulation of intercellular communication by gap junctions in cancer cells have provoked a “bystander” effect, where an increase or decrease in the number or size of intercellular communication junctions intersperses an increase in the diffusion of cytotoxic agents and sensitization to chemotherapeutic agents in addition to the amplification of the therapeutic response [24,56].