GJA1 and breast cancer: CCDC88A/GIV is involved in potentiating tumor cell survival, invasion, and chemoresistance [138], and was shown to interact with Cx43 and co-migrate from Mesenchymal Stromal Cells (MSCs) to ER+ breast cancer cells via Cx43–TNT mediated intercellular transfer, ultimately facilitating metastatic aggression [137].