LEP and neoplasm: Compared with PBS injection, leptin injection significantly increased tumor mass on day 30 (P < 0.01, Figure 6B and 6C), worsened survival (P < 0.05, Figure 6D), exacerbated pulmonary metastasis (P < 0.01, Figure 6E), and elevated the expression of IL-8 and Ki67 in the tumor tissue (P < 0.01, Figure 6G).