Abstract: To explore the effect of IL-33 on various tumor types,exogenous injection of recombinant mouse IL-33 protein (mIL-33) was used to study the efficacy of different subcutaneous tumor-bearing mouse models. In this study,mIL-33 has been found to significantly inhibit the growth of liver,lung,gastric,prostate,and colon cancers. However,the inhibition of tumor growth by mIL-33 was not completely consistent in different types of tumor. A lower dose of mIL-33 (10 μg/kg) significantly inhibited tumor growth in subcutaneous tumor-bearing mice of liver,lung,and gastric cancers,while a higher dose of mIL-33 (90 μg/kg) was required to exert the corresponding antitumor effect in subcutaneous tumor-bearing mouse models with prostate and colon cancers. In addition,the growth inhibitory effect of mIL-33 on subcutaneous tumors of colon cancer was also correlated with the duration of administration and the stage of tumor progression. The results of this study indicate that mIL-33 significantly inhibits the growth of a variety of tumors,suggesting that IL-33 might be an effective target for tumor treatment.