Role of cell-to-cell communication in cancer: New features, insights, and directions.

The current special issue entitled "Role of tunneling nanotubes (TNTs) in carcinogenesis" was designed to discuss the role of cell-to-cell communication, especially TNTs, in cancer pathogenesis. In addition, we discuss the exploitation of TNTs as a potential therapeutic target to prevent and reduce cancer incidence. It is accepted that cell-to-cell communication is essential for the development of multicellular systems, and it is coordinated by soluble factors, associated membrane proteins, exosomes, gap junction channels, and TNTs. An old belief in the cancer field is that cancer cells are "disconnected" from healthy cells, resulting in loss of cell-to-cell communication and neighbor control. However, recent data obtained from different kind of tumors indicate that TNTs and others forms of communication (exosomes and localized cell-to-cell communication) are highly expressed and functional during tumor development . In physiological conditions, TNTs are expressed by few cells, and their main function is to coordinate long-distance signaling. However, upon carcinogenesis, TNTs proliferate and provide an alternative route of communication to enable the transfer of several signaling molecules and organelles to spread disease and toxicity. We propose that TNTs and their cargo are an attractive therapeutic target to reduce or prevent cancer development. All these unique aspects of cell-to-cell diffusion and organelle sharing will be discussed in this special issue.