TNF and neoplasm: Early attempts in Salmonella-based cancer treatment for phase 1 clinical trials using the VNP20009 strain failed in inducing significant tumor regression along with documented side effects at high dosage, and resulted in the research being discontinued [63]; nevertheless, the observed increase of circulating inflammation-related cytokines (TNF-α, IL-6, IL-1β, and IL-12) and tumor colonization noted from biopsies of some patients in the trial [63] prompted scientists and clinicians to improve Salmonella-based treatment.