Klin Onkol 2001; 14(2): 37-45.
Summary: Hypoxic regions are regular finding in tissue of malignant tumors. Hypoxia -decresion of partial pressure of oxygen - is caused by longer distance of some tumor regions from newly created capillars and by insufficiency of newly created capillar network. Various kinds of anaemia in cancer patients potentiate hypoxia in those tumors. Lack of oxygen during radiotherapy and immediately after it and during administration of certain cytostatics causes increase of resistancy of cancer tissues to the treatment methods. Hypoxia in cancer causes three groups of events:
- production of oxygen related proteins enhances a process of tumor metastazing
- genetic instability and selection of more agressive tumorous cells and more agressive behaviour of the tumor
- angiogenesis which enhances atumor progression.