CD40 and cancer: This is an important cytokine that plays a role in cancer, with two protein families implicated in the signaling mediated by the TNF receptor: 1) death-domain proteins, such as TRADD, FADD, TNFR1, RIP; and 2) TRAF domain-containing proteins, such as TNFR2, CD40, TRAF1, TRAF6.