IL18 and neoplasm: The 1,000,000-fold attenuated IL-18, RMP-IL-18mutE6 led to ~50% tumor growth inhibition (TGI), about 2 fold superior to αPD-1 alone but was far less effective than the 10,000-fold attenuated RMP-IL-18mutE4, for which we observed a response in which the tumor volume was below caliper-based detection or “TRs” in four out of five mice.