GJB2 and melanoma: Similarly, in human melanoma lesions, melanoma cells in the invasive and perivascular areas as well as the endothelial cells of the small vessels surrounding the melanoma cell nests expressed Cx26, while melanoma cells residing in the basal layer showed lower levels of Cx26, suggesting that heterotypic GJ-mediated cell–cell adhesion and communication contributes to melanoma metastasis in humans (54, 174, 175).