ROR1 and melanoma: A ROR1 specific siRNA was used to suppress ROR1 expression in those melanoma cell lines that were most sensitive to the direct apoptotic effect of the anti-ROR1 mAbs (ESTDAB049, 075, 112, DFW and A375) as well as the ESTDAB081 melanoma cell line which was resistant to apoptosis by anti-ROR1 mAbs.