GJA1 and breast cancer: Cx43 may have multiple roles in TNTs: Cx43 can directly regulate the formation and length of TNTs in breast cancer cells [58]; Cx43 facilitates TNT formation and mitochondrial transfer between human-induced pluripotent stem cell-derived mesenchymal stem cells and mouse epithelial cells [59]; Cx43 has also been shown to influence the number of TNTs in normal human trabecular mesh cells [60].