The anti-tumor effect of IL-37 results from the suppression of tumor-promoting cytokines, such as IL-1β, which activates IL-6 and TNF, direct effects on tumor cells, and reduction of cell proliferation by interfering with NF-κB, MAPK, and signal transducer and activator of transcription 3 (STAT3). This evidence concerns the gene NFKB1 and neoplasm.