In this report, we aimed to evaluate the involvement of Cx43-GJs at the cytotoxic immunological synapse and the cytotoxic capacity of CTLs using the melanoma-specific pMEL-1 murine model [20] and the B16F10 melanoma cell line, as well as a human HLA-A2-restricted/MART-1-specific CTL clone (CdL43-1) [10] and a HLA-A2+ MART-1+ human melanoma cell line (Mel1) as effector and target tumor cells, respectively. The gene discussed is GJA1; the disease is melanoma.