Studies in colon, breast, lung, fibrosarcoma, prostate and bladder cancer models indicate that IL-4 is not only produced by many cultured tumor cell lines, but that its interaction with IL4-Rα leads to the up-regulation of anti-apoptotic molecules such as cFLIP, PED, FLAME-1 and Bcl-x(L). Here, CFLAR is linked to fibrosarcoma.