Increased expression of TDP-43 was correlated with the poor survival of melanoma patients. (A) Immunohistochemistry analysis showed that TDP-43 had a positive staining rate of 69.5% in melanoma tissue, 22.7% in melanocytic nevi tissue (P = 0.001). (B) Grade positivity by number of positive cells and staining intensity as follow: weak positive (+, <25 % positive in all cells), positive (++, 2550%– positive cells), and strong positive (+++,>50 % positive cells). Out of 128 cases of melanoma tissues, 30.47% were negative staining (−), 29.69% (+), 33.59% (++), and 6.25% (+++). (C) Representative immunohistochemical analysis of TDP-43 expression in melanoma tissue. On the left is negative control, and on the right shows anti-TDP-43 immunostaining strong positive (+++) mainly in cytoplasm. (D) Kaplan-Meier survival curves for groups based on TDP-43. Higher overall 5 year-survival rate was seen in low TDP-43 expression patients than in high TDP-43 expression patients. A positive staining rate <25 % was considered to be low expression, and positive staining rate ≧25% was considered to be high expression. (E) Western Blot showed higher TDP-43 expression in melanoma tissue than that in matching adjacent tissue. (F) Western Blot showed higher TDP-43 expression in melanoma cell lines than that in HM cells. A = adjacent normal tissue, T = tumor tissue.