In this study, we showed that 14 kDa hGH is capable of inhibiting tumor growth, angiogenesis, and metastasis and reducing angiogenesis in endothelial cells; we also showed that the antiangiogenic function of 14 kDa hGH is mediated by the plasminogen activator inhibitor-1 (PAI-1) molecule. The gene discussed is SERPINE1; the disease is neoplasm.