GJA1 and melanoma: Nevertheless, the levels of plasma exosome-derived Cx43 in patients with melanoma whose tumor was situated in the skin, with a size of < 10 cm, Clark level I–III, TNM stage IIb–IV, and had no lymph node metastasis were considerably elevated as opposed to patients with a tumor located in the viscera or mucosa, with a size of ≥ 10 cm, Clark level IV–V, TNM stage IIb–IV and had lymph node metastasis.