For several tumor cell lines, it could be shown that both recombinant TRAIL itself and TRAIL-receptor agonistic antibodies, e.g., mapatumumab and lexatumumab, efficiently sensitize tumor cells to ionizing radiation (Belka et al. 2001; Chinnaiyan et al. 2000; Gong and Almasan 2000; Marini et al. 2009a, b; Niyazi et al. 2009a, b). Here, TNFSF10 is linked to neoplasm.