Mock control B16.F10 melanoma cells did not show cytotoxic activity in the cell reporter bioassay (Fig. 3C, left panel), whereas membrane-bound LIGHT expressed on B16.F10 melanoma cells was functionally active because these cells killed co-cultured mHVEM:Fas reporter cells in an effector to target ratio-dependent manner (Fig. 3C, right panel). Here, FAS is linked to melanoma.