Vaccination against prostate cancer?
New studies raise hopes on such a simple prevention or treatment germinate. But behind it complicated and not yet general methods for the treatment of advanced prostate cancer.
Confusing terms
under vaccination (vaccination, immunization) refers to the artificial creation of an immunity (unresponsiveness) for the prevention of an infectious disease. In active immunization (vaccination), a vaccine is administered (a vaccine of attenuated pathogens or from parts or products of the virus) in the passive vaccination the immune substances produced by the body against infection is obtained is equal to (antibodies). One should therefore in related to the prevention of cancer or even with the not speak of vaccination, but better of immunoprophylaxis or immunotherapy (also why the question mark in the title) treatment. However, concepts such as therapeutic vaccination and tumor vaccine become naturalized. basics The body's immune system is not only for defense against pathogens, but also the elimination of altered cells, such as cancer cells. But why this is not always why it comes to cancer? This central question is still unresolved. The reason for this lies in the seemingly infinitely complicated processes, the abundance of molecules involved (eg genes, messengers, assistants) and cell types. Many of the details are already known, otherwise still being researched. In addition to the mechanisms of carcinogenesis of interest here especially the immunological (the defense system in question) differences between malignant and normal cells. , you'll look in tumors for markers (tracers), especially those that can cause the formation of antibodies (antigens). For since the antigen-antibody binding is specific, this can eliminate tumor cells not only uniquely identified, but also deliberately damage: An artificial antibody can be coupled to the immunodiagnosis of a substance in the body with imaging procedures represented or in the histological (histological ) examination is visible, and for immunotherapy to a substance that the target cells by radiation (radionuclide) or modification of the metabolism harms (cytostatic). Another approach is to prepare the antigen so that the immune system is stimulated and removed the tumor.Previously cytostatic therapy of advanced tumors. Their effect, growth inhibition is due, mainly to the fact that tumor cells grow faster than normal cells. They therefore have a faster metabolism, take on more active and more likely to be damaged. The immunotherapy seems here in the future more selectivity: the effect should be stronger than previously possible or even focus exclusively on tumor cells. immunologically based treatment of prostate cancer prostate cancer when it is so far not been able to identify a causative gene defect, nor to find specific markers. Thus, the application of research must still be limited to operations that generally play a role in the emergence and growth of cancer, as well as markers that mainly, but not exclusively in prostate cancer cells occur (tumor-associated antigens, such as PSA = prostate-specific antigen, PAP = prostatic acid phosphatase, prostate-specific membrane = PSMA antigen). Research is carried out in the laboratory and in part already clinically in patients with advanced, hormone-refractory prostate cancer usually (HRPC, no longer responds to hormone treatment on). Are checked numerous substances that inhibit, for example, growth factors or tumor vascularisation in the tumor or programmed cell death affect the tumor cells (apoptosis). (Inject eg using virus genes in tumor cells or antigens to the immune system present) The gene therapy and the use of artificial, so-called monoclonal antibodies ("passive vaccination") are the subject of research. most advanced are experiments with "vaccines" (vaccines), prepared from whole tumor cells, and to stimulate the immune system for elimination of the tumor. In order to use the patient's own cells (autologous cells), the individual, and thus bear the most appropriate antigens have enough tumor tissue is removed and the vaccine are produced very expensive. In contrast, cells from other patients or from laboratory cell lines (allogeneic cells) are readily available, the vaccine it is but possibly less effective. whereas the same goal, to provoke an immune response, follow DC "vaccines" (from DC, dendritic cells, special defense cells). These cells are obtained from the patient's blood, loaded with tumor antigens and injected again. The studies in this area are also promising, and one of the methods is to stand before the approval. As before, however, is a big problem unsolved: the tumor can escape the attacks of the immune system by different mechanisms. And many open questions, for example about the risks and the durability of the treatment effect and its use in earlier stages of prostate cancer are still to be clarified in future studies.
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