Tumor microenvironment

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As tumor microenvironment , including tumor microenvironment ( Engl. Tumor microenvironment ) called, is known in the oncology the immediate environment of a malignant tumor in an organism . The tumor microenvironment has a decisive influence on carcinogenesis (tumor development).

description

The degenerate cells of an organism that multiply in an uncontrolled manner are called tumor cells . They are characterized by the fact that they are potentially immortal due to permanent and unlimited cell division. They carry genetic mutations , chromosome abnormalities , epigenetic changes, altered metabolism ( glycolysis or Warburg effect ) and the oxygen content of the tissue ( hypoxia ), avoid programmed cell death ( apoptosis ) and they do not react to signals that inhibit cell proliferation . However, these cells are embedded in cell aggregates in which there are also other, non-degenerate cells that do not have these properties. These cells form the tumor microenvironment, which is most commonly composed of fibroblasts , smooth muscle cells , fat cells ( adipocytes ), endothelial cells and cells of the immune system .

In the past, scientific and medical research on tumors was essentially limited to tumor cells. With the beginning of the 1980s, the importance of the surrounding cells was increasingly recognized. These cells actively intervene in the process of tumor growth and in metastasis . In the initial phase of tumor development, these cells try to restrict tumor growth, but are later largely inactivated by certain messenger substances that the tumor cells release or even actively promote tumor growth. The formation of new blood vessels ( neovascularization ), the properties of cancer-associated fibroblasts (also known as tumor- associated fibroblasts , CAF) and tumor-associated macrophages ( tumor associated macrophages , TAM). Often these special fibroblasts and macrophages, as well as other cells of the immune system, are involved in a chronic inflammation of the tumor tissue, which is also considered to be tumor-promoting. In contrast, an acute inflammatory response is usually more useful in combating tumors.

The tumor-promoting cells of the tumor microenvironment serve as sources of new biomarkers and as therapeutic targets in cancer control. A major advantage is the genetic stability of these cells compared to the always genetically unstable cancer cells, which can potentially develop resistance over and over again. This makes the tumor microenvironment a more reliable therapeutic target than the cancer cell itself.

further reading

Individual evidence

  1. ^ P. Dey: Epigenetic changes in tumor microenvironment. In: Indian journal of cancer. Volume 48, Number 4, 2011 Oct-Dec, pp. 507-512, ISSN  1998-4774 . doi: 10.4103 / 0019-509X.92246 . PMID 22293269 . (Review).
  2. ↑ J. Leibovici, O. Itzhaki et al. a .: The tumor microenvironment: part 1. In: Immunotherapy. Volume 3, Number 11, November 2011, pp. 1367-1384, ISSN  1750-7448 . doi: 10.2217 / imt.11.111 . PMID 22053887 . (Review).
  3. ^ D. Spano, M. Zollo: Tumor microenvironment: a main actor in the metastasis process. In: Clinical & Experimental Metastasis . Volume 29, Number 4, April 2012, pp. 381-395, ISSN  1573-7276 . doi: 10.1007 / s10585-012-9457-5 . PMID 22322279 . (Review).
  4. ^ EJ Bernhard: Interventions that induce modifications in the tumor microenvironment. In: Cancer radiotherapy. Volume 15, Number 5, August 2011, pp. 376-382, ISSN  1769-6658 . doi: 10.1016 / j.canrad.2011.01.007 . PMID 21571567 . (Review).
  5. ↑ I. Stasinopoulos, MF Penet u. a .: Exploiting the tumor microenvironment for theranostic imaging. In: NMR in biomedicine. Volume 24, Number 6, July 2011, pp. 636-647, ISSN  1099-1492 . doi: 10.1002 / nbm.1664 . PMID 21793072 . PMC 3146040 (free full text). (Review).