Based on the discovery that silkworm carboxypeptidase inhibitors can inhibit the expression of c-Myc, we designed effective peptides of silkworm carboxypeptidase inhibitors as tumor therapy lead compounds, explored the potential of silkworm carboxypeptidase inhibitors as gastric cancer drugs, and here provide clues for subsequent clinical applications. The gene discussed is MYC; the disease is gastric cancer.