Based on western blot analysis of a panel of melanoma cell lines (Fig. 1A), cell lines A375 and UACC903, expressing low levels of ROR2, were selected for gain-of-function studies and stably transduced with an expression vector encoding human ROR2 or Empty vector as a control (Fig. 1B and Additional file 2: Fig. S1A, B). This evidence concerns the gene ROR2 and melanoma.