Myth 1: Tumor vaccines are used to prevent tumors Unlike the vaccines normally used to prevent infectious diseases, tumor vaccines are generally not used to prevent tumors, but to treat malignant tumors. The function of tumor vaccines is to activate, restore or strengthen the body’s anti-tumor immune response by applying specific, immunogenic tumor antigens to remove residual and metastatic tumor cells. Tumor vaccines are generally classified into 3 categories: the first category is tumor vaccines that enhance tumor immunogenicity. Tumors cannot be recognized by the immune system mainly because they are weakly immunogenic. Therefore, the application of immune adjuvants to enhance the immunogenicity of tumors is a characteristic of early tumor vaccines. Such vaccines are constituted by the addition of adjuvants (e.g., Fuchs’ complete adjuvant, BCG, alum, and Corynebacterium spp.) to autologous or allogeneic tumor cells or lysates of tumor cells. The mechanism of action may be related to the activation of antigen-presenting cells (APCs) by the inflammatory response at the injection site, the production of cytokines and the clustering of B and T cells around the antigen. The second category is genetically modified tumor vaccines. Tumor cells are not recognized by the immune system because they lack major histocompatibility complex (MHC) II molecules and B7 complex-stimulating molecules, as well as the inability to secrete cytokines that enhance the body’s immunity. However, APC has these functions, and if tumor cells are genetically modified to produce APC-like functions, they will be able to elicit an immune response from the body. In the late 1980s, with the development of gene transfer technology and people’s in-depth understanding of the immune system, people were able to genetically modify tumor cells in accordance with the characteristics of APC processing and antigen presentation to make genetically modified tumor vaccines. The second category of tumor vaccines also includes tumor vaccines based on recombinant plasmids, viruses or bacteria. The third category of tumor vaccines are dendritic cell-based tumor vaccines. Evidence suggests that the mechanism by which many tumor cells fail to elicit anti-tumor immune action in the body is not due to a lack of tumor antigens, but rather the inability of the body’s APCs to present tumor antigens to the immune system. Dendritic cells are known to be the cells with the strongest antigen-presenting ability in the organism, which can capture antigens and transmit the information to T and B lymphocytes, thus triggering a series of specific immune response reactions. Therefore, if tumor antigens are injected into dendritic cells, a specific anti-tumor immune response can be elicited. This approach has been successful in animal models, resulting in anti-tumor-specific immune responses and inhibiting the growth of murine tumors. Myth 2 Try tumor vaccines when radiation and chemotherapy don’t work Tumor vaccines are most appropriately applied to patients with early stage as well as post-radical surgery tumors, rather than patients with advanced tumors. As mentioned above, tumor vaccine is used to help the body’s immune system to remove the residual and metastatic tumor cells, the number of residual tumor cells in early stage and post radical surgery tumor patients is small, and the patient’s physical condition is better, and the immune system is more sound, the immune system and the tumor cells are equal opponents, and with the help of tumor vaccine, there is a hope that the immune system can eliminate the residual tumor cells, and achieve long term survival or even cure. They can achieve long-term survival or even be cured. However, patients with advanced stage have a large tumor load and their immune system is basically in a semi-paralyzed state, just like an incompetent dog that can not be helped, so the use of tumor vaccines will not be helpful either. Therefore, it is suggested to patients who are found to be suffering from tumors: if your disease is still in the early stage and can be treated by surgery, please consider the issue of using your own surgical specimen as the antigen to prepare individualized tumor vaccine as early as possible before the surgery and contact the relevant experts, because if the tumors cut off after the surgery have already been fixed by reagents in the Department of Pathology, they will no longer be suitable for preparing tumor vaccine, and it will be too late for regrets.