Gene therapy of tumor 1. What is gene? Genes are the biological units of inheritance. Genes determine the outward characteristics of organisms, such as hair and eye color; more subtle characteristics, such as the ability of blood to carry oxygen; and some complex characteristics, such as the physical representation when subjected to the combined effects of multiple genes and the environment. Genes are the building blocks of deoxyribonucleic acid (DNA) molecules. Humans have approximately 30,000 genes. Genes carry instructions that direct cells to produce specific proteins, such as enzymes. A gene in a cell is activated only at a specific stage. Whether or not certain genes are activated in a cell determines the composition of proteins, and thus the type and function of the cell. Abnormalities in genes will lead to the development of diseases. Xubo Wang, Department of Pathology, Xuzhou Hospital of Traditional Chinese Medicine 2. What is gene therapy? Gene therapy is a biomedical treatment based on changing the genetic material of a person. It is a biomedical high technology that introduces normal genes or genes with therapeutic effects into human target cells in a certain way to correct the defects of genes or to play a therapeutic role, so as to achieve the purpose of treating diseases. Unlike conventional treatments, gene therapy targets the root cause of the disease, the abnormal gene itself. Gene therapy for tumor is to inhibit and interfere with tumor cells by using the principle of gene, so as to inhibit gene replication, transcription, splicing, transfer and translation at multiple levels, reverse the malignant phenotype of cells, induce apoptosis, and inhibit the growth of tumor cells, and finally cause the complete loss of tumor growth ability to achieve the purpose of curing tumor.